ANNUAL O F SCIENTIFIC DISCOVERY: O R YEAR-BOOK OF FACTS IN SCIENCE AND ART FOR 1861. EXHIBITING THE HOST IMPORTANT DISCOVERIES AND IMPROVEMENTS I X MECHANICS, USEFUL ARTS, NATURAL PHILOSOPHY, CHEMISTRY, ASTRONOMY, GEOLOGY, ZOOLOGY, BOTANY, MINERALOGY, METEOROLOGY, GEOGRAPHY, ANTIQUITIES, ETC. TOGETHER WITH NOTES ON THE PROGRESS OF SCIENCE DURING THE YEAR 1860; A LIST OF RECENT SCIENTIFIC PUBLICATIONS; OBITUARIES OF EMINENT SCIENTIFIC MEN, ETC. EDITED BY DAVID A. WELLS, A.M., AUTHOR OP PRINCIPLES OF NATURAL PHILOSOPHY, PRINCIPLES OP CHEMISTRY, SCIENCE OF COMMON THINGS, ETC. BOSTON: GOULD AND LINCOLN, 59 WASHINGTON STREET. NEW YORK: SHELDON AND COMPANY. CINCINNATI : GEORGE S. BLANCHARD. LONDON: TRUBNER & CO. 1861. Entered according to Act of Congress, in the year 1861, by GOULD AND LINCOLN, In the Clerk's Office of the District Court of the District of Massachusetts. t A P A N D O V E R : ELECTROTYPED AND PRINTED BY W . F . D K A P E K . NOTES BY THE EDITOR ON THE PROGRESS OF SCIENCE FOR THE YEAR 1860. THE fourteenth meeting of the American Association for the Ad- vancement of Science was held August 18, 1860, at Newport, R I. Isaac Lea, Esq., of Philadelphia, in the chair. The whole number of papers registered for presentation was 78. The number of members in attendance was small, only 140 names appearing on the register during the continuance of the meeting. " Neither can we," says the editor of Si.llimans Journal, in commenting on the meeting, " conceal the fact, that while many papers of marked, ability were presented, the character of this meeting was not in all respects creditable to American science. A conviction prevailed among many who were present at Newport of a decadence in the scientific character of the Association, of a loss of tone, which, if not already a demoralization, threatened soon to become such." The Association adjourned, to meet in Nashville, Tennessee, in April, 1861. The officers of the Nashville meeting are : President, F. A. P. Barnard, LL.D., President of the University of Mississippi; Vice President, Dr. Robt. YV. Gibbes, of South Carolina ; General Secre- tary, Prof. J. W. Mallet, of Mississippi ; Treasurer, Dr. A. L. Elwyn, of Philadelphia. The thirtieth annual meeting of the British Association for the Ad- vancement of Science was held at Oxford, June, 1860, Lord Wrottes- ley in the chair ; and was one of the most successful meetings since the foundation of the Association. The meeting for 1861 was appointed to be held at Manchester Mr. Fairbairn, the celebrated English engineer, being the President elect. From the address cf the President on the " Progress of Science " since the previous meeting, we make the following extracts : - - " The observations of our private astronomical observers have been chiefly devoted to seven important objects : First, the observing and map- ping of the smaller stars, under which term I include all those which do not form the peculiar province of the public observer ; secondly, IV NOTES BY TUE EDITOR the observations of the positions and distances of double stars ; thirdly, observation?, delineations, and catalogues of the nebuUe ; fourthly, observations of the minor planets ; fifthly, cometary observations ; sixthly, observations of the solar spots, and other phenomena on the sun's disk ; seventhly, occultations of stars by the moon, eclipses of the heavenly bodies, and other occasional extra-meridional observations. " And, first, as to cataloguing and mapping the smaller stars. This means, as you know, the accurate determination by astronomical obser- vation of the places of those objects, as referred to certain assumed fixed points in the heavens. The first Star Catalogue, worthy to be so called, is that which goes by the name of Flamsteed's, or the British Catalogue. It contains above 3000 stars, and is the produce of the labors of the first Astronomer Royal of Greenwich. About the middle of the eighteenth century, the celebrated Dr. Bradley, who also filled the post of Astronomer Royal, observed an almost equally extensive Cata- logue of Stars, and the beginning of the nineteenth century gave birth to that of Piazzi of Palermo. These three are the most celebrated of what may be now termed the ancient Catalogues. About the year 1830, the attention of modern astronomers was more particularly directed to the expediency of reobserving the stars in these three Cat- alogues ; a task which was much facilitated by the publication of a very valuable work of the Astronomical Society, which rendered the calculations of the observations to be made comparatively easy ; and, accordingly, observations were commenced and completed in several public and private observatories, from which some curious results were deduced ; as, e. g., sundry stars were found to be missing, and others to have what is called k proper motion.' And now a word as to the utility of this course of observation. It is well observed by Sir John Uerschel, ' that the stars are the landmarks of the universe ; every well-determined star is a point of departure which can never deceive the astronomer, geographer, navigator, or surveyor.' We must have these fixed points in order to refer to them all the observations of the wandering heavenly bodies, the planets and the comets. By these fixed marks we determine the situation of places on the earth's sur- face, and of ships on the ocean. When the places of the stars have been registered, celestial charts are constructed ; and by comparing these with the heavens, we at once discover whether any new body be present in the particular locality under observation ; and thus have most of the fifty-seven small or minor planets between Mars and Jupiter been discovered. The observations, however, of these smaller stars, and the registry of their places in Catalogues, and the comparisons of the results obtained at different and distinct periods, have revealed another extraordinary fact, no less than that our own sun is not fixed in space, but that it is constantly moving forward towards a point in the constellation Hercules, at the rate, as it is supposed, of about 18,000 miles an hour, carrying with it the whole plane iary and cometary sys- ON THE PROGRESS OF SCIENCE. V tern ; and if our sun moves, probably all the other stars or suns move also, and the whole universe is in a perpetual state of motion through space. " The second subject to which the attention of private observers has been more particularly directed is that of double or multiple stars, or those which, being situated very close to one another, appear single to the naked eye, but when viewed through powerful telescopes are seen to consist of two or more stars. The measuring the angles and dis- tances from one another of the two or more component stars of these systems has led to the discovery that many of these very close stars are, in fact, acting as suns to one another, and revolving round their common centre of gravity, each of them probably carrying with it a whole system of planets and comets, and, perhaps, each carried for- ward through space like our own sun. It became then a point of great interest to determine whether bodies so far removed from us as these systems observed Newton's law of gravity ; and to this end it was necessary to observe the angles and distances of a great number of these double stars, scattered everywhere through the heavens, for the purpose of obtaining data to compute their orbits. This has been done, and chiefly by private observers, and the result is that these distant bodies are found to be obedient to the same laws that prevail in our own system. " Of all the phenomena of the heavens, there are none which excite more general interest than comets, and though the larger and brighter comets naturally excite most general public interest, and are really val- uable to astronomers, as exhibiting appearances which tend to throw light on the internal structure of these bodies, and the nature of the forces which must be in operation to produce the extraordinary phenomena observed, yet some of the smaller telescopic comets are, perhaps, more interesting in a physical point of view. Thus the six periodical comets, the orbits of which have been determined with tolerable accuracy, and w r hich return at stated intervals, are extremely useful, as being likely to disclose the facts of which, but for them, we should possibly have ever remained ignorant. Thus, for example, when the comet of Encke, which performs its revolution in a period of a little more than three years, was observed at each return, it disclosed the important and unexpected fact that its motion was continually accelerated. At each successive approach to the sun it arrives at its perihelion sooner and sooner ; and there is no way of accounting for this so satisfactory as that of sup- po^ing that the space in which the planetary and cometary motions are performed is everywhere pervaded by a very rarefied atmosphere or ether, so thin as to exercise no perceptible effect on the movements of massive solid bodies, like the planets, but substantial enough to exert a very important influence on more attenuated substances moving with great velocity. The effect of the resistance of the ether is to retard the tangential motion, and allow the attractive force of gravity to draw the 1* VI NOTES BY THE EDITOR body nearer to the sun, by -which the dimensions of the orbit are con- tinually contracted and the velocity in it augmented. The final result will be that, after the lapse of ages, this comet will fall into the sun ; this body, a mere hazy cloud, continually flickering, as it were, like a celestial moth round the great luminary, is at some distant period des- tined to be mercilessly consumed. Now the discovery of this ether is deeply interesting as bearing on other important physical questions, such as the undulatory theory of light; and the probability of the future absorption of comets by the sun is important as connected with a very interesting speculation by Professor Win. Thomson, who has suggested that the heat and light of the sun may be from time to time replenished by the falling in and absorption of countless meteors which circulate round him ; and here we have a cause revealed which may accelerate or produce such an event. " On the 1st of September last, at eighteen minutes past 11 A. M., a distinguished astronomer, Mr. Carrington, had directed his telescope to the sun, and was engaged in observing his spots, when suddenly two intensely luminous bodies burst into view on its surface. They moved side by side through a space of about 35,000 miles, first increasing in brightness, then fading away ; in five minutes they had vanished. They did not alter the shape of a group of large black spots which lay directly in their paths. Momentary as this remarkable phenomenon was, it was fortunately witnessed and confirmed, as to one of the bright lights, by another observer, Mr. Hodgson, at Highgate, who, by a happy coincidence, had also his telescope directed to the great luminary at the same instant. It may be, therefore, that these two gentlemen have actually witnessed the process of feeding the sun, by the fall of meteoric matter ; but, however this may be, it is a remarkable circum- stance, that the observations at Kew show that on the very day, and at the very hour and minute of this unexpected and curious phenomenon, a moderate but marked magnetic disturbance took place ; and a storm, or great disturbance of the magnetic elements, occurred four hours after midnight, extending to the southern hemisphere. Thus is exhib- ited a seeming connection between magnetic phenomena and certain actions taking place on the sun's disk, a connection which the obser- vations of Schwabe, compared with the magnetical records of our colonial observatories, had already rendered nearly certain. " In chemistry I am informed that great activity has been displayed, especially in the organic department of the science. For several years past processes of substitution (or displacement of one element or organic group by another element or group more or less analogous) have been the main agents employed in investigation, and the results to which they have led have been truly wonderful; enabling the chemist to group together several compounds of comparatively simple constitution into others much more complex, and thus to imitate, up to a certain point, the phenomena which take place within the growing plant or ON THE PROGRESS OF SCIENCE. VII animal. It is not, indeed, to be anticipated that the chemist should ever be able to produce, by the operations of the laboratory, the arrangement of the elements in the forms of the vegetable cell or the animal fibre ; but he may hope to succeed in preparing some of the complex results of secretion or of chemical changes produced within the living organism, changes which furnish definite crystallizable compounds, such as the formiates and the acetates, and which he has actually obtained by operations independent of the plant or the ani- mal. Hofmann, in pursuing the chemical investigation of the remark- able compound which he has termed Triethylphosphine^ has obtained some very singular compound ammonias. Triethylphosphine is a body which takes fire spontaneously when its vapor is mixed with oxygen, at a temperature a little above that of the body. It may be regarded as ammonia in which an atom of phosphorus has taken the place of nitro- gen, and in which the place of each of the three atoms of hydrogen in ammonia is supplied by ethyl, the peculiar hydrocarbon of ordinary alcohol. From this singular base Hofmann has succeeded in procuring other coupled bases, which, though they do not correspond to any of the natural alkalies of the vegetable kingdom, such as morphia, quinia, or strychnia, yet throw some light upon the mode in which complex bodies more or less resembling them have been formed. " The bearing of some recent geological discoveries on the great question of the high antiquity of Man was brought before your notice at your last meeting by Sir Charles Lyell. Since that tune many French and English naturalists have visited the valley of the Somme in Picardy, and confirmed the opinion originally published by M. Boucher de Perthes, in 1847, and afterwards confirmed by Mr. Prest- wich, Sir C. Lyell, and other geologists, from personal examination of that region. It appears that the position of the rude flint-implements, which are unequivocally of human workmanship, is such, at Abbeville and Amiens, as to show that they are as ancient as a great mass of gravel which fills the lower parts of the valley between those two cities, extending above and below them. This gravel is an ancient fluviatile alluvium by no means confined to the lowest depressions (where extensive and deep peat-mosses now exist), but is sometimes also seen covering the slopes of the boundary hills of chalk at eleva- tions of eighty or one hundred feet above the level of the Somme. Changes, therefore, in the physical geography of the country, compris- ing both the filling up with sediment and drift, and the partial reexca- vation of the valley, have happened since old river-beds were, at some former period, the receptacles of the worked flints. The number of these last, already computed at above fourteen hundred in an area of fourteen miles in length and half a mile in breadth, has afforded to a succession of visitors abundant opportunities of verifying the true geological position of the implements. " The old alluvium, whether at higher or lower levels, consists not VIII NOTES BY THE EDITOR only of the coarse gravel with worked flints above mentioned, but also of supers-imposed beds of sand and loam, in which are many fresh- water and land shells, for the most part entire, and of species now living in the same part of France. "With the shells are found bones of the mammoth and an extinct rhinoceros, R. tichorhinus, an extinct species of deer, and fossil remains of the horse, ox, and other ani- mals. These are met with in the overlying beds, and sometimes also in the gravel where the implements occur. At Menchecourt, in the suburbs of Abbeville, a nearly entire skeleton of the Siberian rhinoce- ros is said to have been taken out about forty years ago, a fact afford- ing an answer to the question often raised, as to whether the bones of the extinct mammalia could have been washed out of an older alluvium into a newer one, and so redeposited and mingled with the relics of human workmanship. " The exploration of caverns, both in the British Isles and other parts of Europe, has in the last few years been prosecuted with renewed ardor and success, although the theoretical explanation of many of the phenomena brought to light seems as yet to baffle the skill of the ablest geologists. Dr. Falconer has given us an account of the remains of several hundred hippopotami, obtained from one cavern, near Palermo, in a locality where there is now no running water. The same palaeon- tologist, aided by Colonel Wood, of Glamorganshire, has recently extracted from a single cave in the Gower peninsula of South Wales a vast quantity of the antlers of a reindeer, perhaps of two species of reindeer, both allied to the living one. These fossils are most of them shed horns; and there have been already no less than eleven hundred of them dug out of the mud filling one cave. " In the cave of Brixham, in Devonshire, and in another near Paler- mo, in Sicily, flint implements were observed by Dr. Falconer, associated in such a manner with the bones of extinct mammalia, as to lead him to infer that man must have coexisted with several lost species of quad- rupeds; and M. de Vibraye has also this spring called attention to analogous conclusions, at which he has arrived hy studying the posi- tion of a human jaw with teeth, accompanied by the remains of a mammoth, under the stalagmite of the Grotto d'Arcis, near Troyes, in France." An international congress of persons interested in chemical pursuits was held at Carlsruhe, Germany, in September, 1860, Dumas of Pa"ris being in the chair. The attendance was large, and although a great majority of those present, as might have been expected, were Ger- mans, yet representatives from many other parts of the world were not wanting. The proceedings lasted some days, and a detailed account of the deliberations is to be published. Among the questions submitted for general discussion were the following ; Would it be judicious to establish a difference between the term atom and molecule ? ON THE PROGRESS OF SCIENCE. IX Is the idea of equivalents empirical and independent of the idea of atom or molecule V Would it be desirable to place chemical notation in harmony with the progress of science ? The last question was answered with much emphasis in the affirma- tive ; but M. Dumas thought the time had not yet come to adopt a definite method of notation. He wished, however, to see at once added to the system of Berzelius the modifications which were rendered ne- cessary by the recent progress of organic chemistry. One important point to which he called the attention of the congress was the necessity of looking at the requirements of instruction : in this respect unity in language and theory seemed to be most desirable. The President concluded by expressing the hope that the meeting would not be the last, and that next year the European chemists would again meet to discuss some of the points of a science cultivated at present with so much ardor and success. In the department of geographical research, the past two or three years have been periods of great activity ; and especially in the ex- ploration of Central Africa the zeal of explorers seems to have been greatly increased* " The earlier discoveries of Livingstone," says Sir R. I. Murchison, in Ms address before the Section of Geography and Ethnology, at the last meeting of the British Association, " have been followed by other researches of his. companions and himself, which, as far as they go, have completely realized his anticipation of detecting large elevated tracts, truly Sanatoria as compared with those swampy, low regions near the coast, which have impressed too generally upon the minds of our countrymen the impossibility of sustaining a life of exertion in any inter-tropical region of Africa. The opening out of the Shire river, that grand affluent of the Zambesi, with the description of its banks and contiguous lofty terraces and mountains, and the devel- opment of the healthfulness of the tract, is most refreshing knowledge, the more so as it is accompanied by the pleasing notice that in this tract the slave-trade is unknown, except by the rare passage of a gang from other parts; whilst the country so teems with rich vegetable products, including cotton and herds of elephants, as to lead us to hope that a spirit of profitable barter, which powerfully animates the natives, may lead to their civilization, and thus prove the best means of eradicat- ing the commerce in human beings. Whilst Livingstone was sailing to make his last venture, Captains Burton and Speke were returning from their glorious exploits into a more central and northern region of South Africa, where they had discovered two great internal lakes, or fresh- water seas, each of them not less than three hundred miles in length. I may here notice, to the honor of our government, that Captain Speke, associated with another officer of the Bengal army, Captain Grant, has received 2500, to enable him to terminate his examination of the great Nyanza lake, under the equator, and we have reason to hope X NOTES BY THE EDITOR that he will find the chief feeders of the White Nile flowing out from its northern extremity, and thus determine the long-sought problem of one of the chief sources of that classic stream." Cooler, the English geographer, has published an article in sup- port of his belief that the great lake Nyanza, the southernmost por- tion of which has been described by Livingstone, and visited by several of the Portuguese explorers, is identical with the Tanganyika, the northern end of which was discovered by Burton and Speke. If this theory be true, then we shall have a great inland sea, available for navigation, eight hundred and forty nautical miles in length, and extending from latitude 2 to 12 south of the equator. At the last meeting of the British Association, the following com- munication on Antarctic explorations, addressed by Captain Maury, U. S. N., to Lord Wrottesley, the President, was received and read: " My Dear Lord Wrottesley, I hope the time is not far distant when circumstances will be more auspicious than at present they seem, for, as soon as there appears the least chance of success, I shall urge the sending from this country an exploring expedition to the eight millions of unknown square miles about the south pole. An expedition might be sent from Australia, with little r no risk. Two propellers, or even two vessels with auxiliary steam-power, might be sent out, so as to spend onr three winter months in looking for a suit- able point along the Antarctic continent to serve as a point of depart- ure for overland or over-ice parties. Having found one or more such places, vessels, properly equipped for land and ice and boat expedi- tions, might be sent the next season, there to remain, seeking to pene- trate the barrier, whether of mountain or of ice, or both, until the next season, when they might be relieved by a fresh party, or return home to compare notes, and be governed accordingly. You know the barometer, at all those places which have a rainy and a dry season, stands highest in the dry, lowest in the wet. Now I do not find any indications that the Antarctic barometer has months of high range ; it is low all the year. Therefore, if I be right in ascribing the apparent tenuity of the air there to the heat that is liberated during the con- densation of vapor from the heavy precipitation that is constantly taking place along the sea front of those ' barriers,' we should be correct in inferring that the difference in .temperature between the Antarctic summer and winter is not very marked. If, in a case like this, we might be permitted to indulge the imagination, we might fancy the ' barrier ' to be a circular range of mountains, and that beyond these lies the great Antarctic basin. Beyond this range, as beyond the Andes, we may fan^y a rainless region, as in Peru, a region of clear skies and mild climates. Though the air in passing this range might be reduced below the utmost degree of Arctic cold, yet being robbed of its vapor, it would receive as sensible the latent ht-at thereof. Passing oii' to the polar slope of these mountains, this air, ON THE PROGRESS OF SCIENCE. XI then, would be dry air ; descending into the valleys, and coming under the barometric pressure at the surface, it would be warm air. Leslie has explained how, by bringing the attenuated air down from the snow line, even of the tropics, and subjecting it to the barometric weight of the superincumbent mass, we may raise its temperature to inter-tropi- cal heat by the mere pressure. In like manner this Antarctic air, though cold and rare while crossing the ' barrier,' yet receiving heat from its vapors as they are condensed, passing over into the valleys beyond, and being again subjected to normal pressure, may become warm. We have abundant illustrations of the modifying influences upon climate which winds exercise after having passed mountains and precipitated their vapor. The winds which drop the waters of the Columbia river, etc., on the western slopes of the Rocky Mountains, make a warm climate about their base on this side, so much so that we find in Nebraska the lizards and reptiles of Northern Texas. Indeed trappers tell me that the Upper Missouri is open in fall long after the Lower is frozen up, and in spring long before several weeks the ice in the more southern parts has broken up. The eastern slopes of Patagonia afford even a more striking illustration of climates being tempered by winds that descend from the mountains bearing with them the heat that their vapor has set free. Thus you observe that an exploring party after passing the barrier might, as they approach the pole, find the Antarctic climate to grow milder instead of colder. It would be rash in the present state of our information to assert that such is the case ; but that such may be the case should not be ignored by the projectors and leaders of any new expedition to those regions. The existence of an open sea in the Arctic Ocean has, with a great degree of probability, been theoretically established. But the circumstances, as strong as they are, which favor the existence of an open water there, are not so strong and direct as are the proofs and indications of a mild polar climate in the Antarctic regions. I have examined the immense library of lo^-books here for the lines of / r> Antarctic ice-drift. There appear to be two, both setting to the north- east, one passing by the Falkland Islands, the other having its north- ern terminus in the regions about the Cape of Good Hope. Further south, icebergs are found all around ; but in these lines of drift they are found nearest the equator. The space between the Falkland drift and the Good Hope drift is an unfrequented part of the ocean. It may, therefore, be one broad drift, the edges of which only I have pointed out. The most active currents from the south do not run with this ice. Humboldt's current is the most active, but it does not get its icebergs as far north as they come by these lines. This cir- cumstance has suggested the conjecture that one part of the Antarctic Continent must be peculiarly well situated for the formation of gla- ciers and the launching of icebergs. These lines of drift point to such a place." XII NOTES BY THE EDITOR An Arctic expedition, organized by public subscriptions, to follow substantially the route of Dr. Kane, and to attempt to reach the open Polar Sea, sailed during the past summer from Boston, under the command of Dr. Isaac L. Hayes (surgeon of the Kane expedition), with Dr. Sontag as astronomer. The expedition was at Upernavik August 14th, from whence Dr. Hayes writes as follows: "I anticipate reaching Cape Frazer, lat. 70 42', where I propose spending the winter. A degree lower, however, will place one within practicable reach of my proposed field of exploration. If the condi- tion of the ice will permit, I will immediately, after a -winter harbor has been selected, carry forward the boat which I intend using for next summer's labors, and some provisions, as far north as possible, and then leave them, secured against the bears, and return to the schooner after the winter has firmly set the ice. Early next spring we shall push forward advance depots, and, should we find either ice or water, we shall endeavor to accomplish with boats or sledges, or with both, the chief object of the voyage before the close of the summer. If this fortune awaits us, we shall then return home without unneces- sary delay. I do not, however, anticipate this result, but I expect that we shall be detained two winters. I shall endt avor, by every means, to avoid a third year's absence. Y\ r e carry with ns, however, food and fuel for that period, and, in the event of our being so long detained, I do not fear adverse results. AVith the fresh supplies we have on board, I believe we can resist the scurvy." The act of Congress of June 22, 1860, authorized the President to send some competent person or persons to the Isthmus of Chiriqui, to examine and report upon the quality and probable quantity of coal to be found on the lands of the Chiriqui Improvement Company, the character of the harbors of Chiriqui Lagoon and Golfito, and the practicability of building a railroad across said isthmus, so as to con- nect said harbors. An expedition was accordingly sent, under the command of Captain Engle, U. S. N., with Lieutenants Jeffers and Morton as engineer officers, and Dr. Evans as geologist. The reports of these o-entlemen show that the harbors on both sides of the Isthmus o of Chiriqui are unsurpassed ; that, in the opinion of Lieutenant Mor- ton, " it is entirely practicable to connect the harbors by a line of railroad adapted to commercial purposes ; " and that the coal found there is of excellent quality, and the supply inexhaustible. The discussion of the observations of the U. S. astronomical expe- dition to Chili, under Lieut. Gillis, conclusively establishes the fact that Valparaiso, and probably the whole coast of Chili, as laid down on the best charts (those of the British Admiralty), are four and four- fifths miles too far to the west, an error of much importance to navi- gators. The State Geological survey of California has been organized during the past year by the appointment of Prof. J. D. Whitney as ON THE PROGRESS OF SCIENCE. XIII geologist, Mr. "William Ashburner filling the post of assistant geologist, and Prof. W. H. Brewer that of agricultural chemist and botanist. The act authorizing the survey also contemplates the establishment of a state museum upon a most extensive scale ; and the whole enter- prise is started on a most liberal and enlightened basis, and com- mences under more favorable auspices than any similar work hitherto projected in this country. Dr. Newberry, the well-known geologist of Ohio, has returned to his home during the past year, after successful geological explorations in New Mexico and Utah. Some of the results ot' his labors are noticed in the American Journal of Science as follows : " His collection of fossils is very large, offering conclusive evidence of the geological structure of a very large area. Of the Cretaceous deposits he was fortunate in obtaining a peculiarly satisfactory analy- sis. Contrary to all our previous notions, these beds turn out to be much more largely developed, tliat is, existing in much greater force, stratigraphically, west of the Rocky Mountains than east of them. In Southern Utah (just where Marcou claims there are no Cretaceous rocks) he found beautiful exposures, of four thousand feet in thickness, of strata of that age, with abundant fossils, both animal and vegetable. The bones of a huge Saurian are among Dr. Newberry's novelties." M. de Khanikoff has published a map of levelling*, made by him in 1859, in Khorassan, Afghanistan, Seistan, and Central Persia, over an extent of two hundred thousand square miles. They are located by a triangulation connected with the triahgulation of Trans-Caucasia. This vast country is subdivided into four terraces of unequal extent, and with a mean height of fifteen hundred to three thousand feet, each having a central depression and forming a ba>in. The first and largest contains the great desert between Koum and Nichapoor ; the second and southwestern, which is the driest of all, is the desert of Loot, between Khorassan and Irak ; the third, the desert of Seistan, has at its lowest point Lake Hamoon ; and the fourth occupies the country between Toon Khaf and Selzar. The mountains which fur- row these terraces are composed mainly of crystalline rocks, and are remarkable for their uniformity and for the extreme dryness of their slopes. The vegetation of the first and last named terraces is iden- tical with that of the plains of Transoxiania ; the others present some plants of tropical forms, similar to those of Southern Arabia. Wher- ever the country is sheltered against the cold northern winds, the date-tree is cultivated with success. A geological survey of Norway is now going on, under the direc- tion of Prof. Kjerulf, of the University of Christiana. The greater part of Southern Norway is already surveyed, and the northern part, it is expected, will be soon completed. In 1858 the Imperial Academy of Science of St. Petersburg sent two young Russian naturalists, Messrs. Sjiiwerzow and Borschtschow, 2 XIV NOTES BY THE EDITOR on a geological and botanical expedition to the steppes of the Kirghiz. A brief account of their explorations has just been published. The most remarkable result attained was the discovery, on the northeastern side of the Aral, of a completely marine flora, consisting of numerous species which are found in no other inland body of water, whether salt or fresh. It has been known for some time that the mollusca of the Aral, if not identical with those of the ocean, were at least very similar to them. These two facts go far to prove that the Caspian and the Aral formed originally a portion of one great oceanic bay. General Schubert has communicated to the Academy of Sciences of St. Petersburg a determination of the figure of the earth based on the principal measurements of degrees ; he believes that it is an ellip- soid with three axes, or, in other words, that not only the meridians are ellipses, but that the equator is also an ellipse, though differing very slightly from a circle. The King of Bavaria is having executed, at his own expense, a magnetic chart of Europe, to which several years of labor have already been devoted. M. Lamont, director of these works, has addressed to the Academy of Sciences of Paris, through the interven- tion of M. Eiie de Beaumont, curious and important details upon the determination of the constant inclinations of the magnetic needle in the South of France and of Spain. Mariners will profit by the table of the declinations of the needle in the principal ports of France, Spain, and Portugal, traced by this savant. The declination is at Toulon, 16 45' west; at Marseilles, 17 7'; at Oporto, 22 lp'; at Brest, 22 33'; at Cherbourg, 21 38'; at Dimkerque, 20 10', etc. This declination has, within a century, been diminishing at an aver- age rate of seven minutes per annum. During the past year the Museum of Comparative Zoology, insti- tuted at Cambridge, Mass., by Professor Agassiz, and for the founda- tion and endowment of which $225,000 was raised from the state and by private subscription, has been so far completed as to be formally dedicated and opened to the public. The plan adopted by Professor Agassiz differs essentially from that of any other museum in the world. His aim has been to make the collection help the student by the sim- plicity and progressive character of the arrangement, instead of per- plexing him by the multitude of different objects to be studied. The student finds, first, a simple collection of the representatives of the four great types of animals, arranged as a vestibule, as it were, to the com- plete collection, so that the beginner who has not made his first step in zoology, or the visitor not conversant with the objects of the institu- tion, can within half an hour obtain an index, as it were, of the principles of zoology, and learn the essential characteristics of the four great types of the animal kingdom, so as to recognize precisely wha.t radiates, what molluscs, what articulates, and what vertebrates are. Next in order are representatives of the above classes arranged ON THE PROGRESS OF SCIENCE. XV for comparative examination and study. There is then to be a collec- tion of animals, or fossils, arranged according to their palseontological character, that is to say, according to the geological ay positive observations and measurement found that this was really what became of the water dis- placed by the bow of the boat. On one occasion he drew so large a number of boats along a canal in one direction, on a certain day, that the waves carried a great part of the water from one end of the canal to the other, and in the evening the water in the canal was found raised eighteen inches at one end, and depressed to the same extent at the other. The velocity with which the travelling wave moved was found to depend entirely on the depth of the water. At 3 feet deep the wave travels 6 miles an hour U Cj U U U g U (I (C 7 U U U JO CC :. j ( -| U U U J2 " *' " 15 " " " 15 " " 20 " " u 18 " " " 30 " " " 20 " " " 40 " " " 25 " " " 50 " " " 30 " " In addition to a constant velocity, this wave has a constant shape, a drawing of which was exhibited by the author. And a most extraordinary circumstance was, that its form corresponded exactly with the form of bow which he had previously, and from altogether different considerations, con- structed as the form of least resistance. Moreover, he found that what he had endeavored to do in constructing that form, viz., move the particles of water gradually out of the way, from one position of rest to another, the travelling wave also did ; for on closely observing the water in the experi- mental trough under the action of such a wave, he observed that it lifted every particle of water over which it passed out of one place forward into another place, and there left it perfectly at rest. In the travelling wave, therefore, as in ordinary waves, the particles of water composing it were continually being replaced by others, while the wave itself advanced without apparent change. The foregoing facts convinced the author that the form of bow which he had adopted, and which has since been called the " wave form," was analogous and conformable to the nature of water and of wave motion. Like many others, the author at first thought that the stern of a vessel ought to be of the same form as the bow; but thought it proper to under- take a series of experiments, with the view of ascertaining what happened when a hole in the water had to be filled up. Where did the water that filled it come from? and how did it come? He first found that the hollow made in the water had no tendency to travel with an independent velocity of its own, but moved just as fast, and only as fast, as the body which pro- duced it. He then discovered that the currents of water rushing into such a hollow, from different directions, met, and produced a wave, which he called the " following wave," or the "refilling" or "replacing wave," and which always moved with the velocity of the ship, and had nothing to do with the depth of the water. The " following wave" also repeated itself in an endless series astern of the vessel. The author explained that the nature of this wave required that the stern of the ship should be formed of cycloidal curves, and showed how this fact was applied in actual construction. MECHANICS AND USEFUL ARTS. 21 * The fiuthor might be asked, reverting to the wave at the bow, What became of the water at the bow, supposing he dragged the boat faster than the water could spread itself? The answer was : With only a moderate force at his disposal the boat could not be made to travel faster; but if he had force enough to compel it to go in spite of the water, the water would rise up and stand on both sides of the boat until the load had passed, and then fall down into the hole left behind it. In a shallow canal in Scotland, where the carrier-wave travelled only seven miles an hour, he had compelled a boat to go ten miles, and he found that the water not only rose up, but lifted the boat with it, so that she drew less water than before, and actually went easier at ten miles an hour than at five. Had not railways come into fashion just at the time, the country would have been covered with little troughs, and people would have been riding on the tops of these waves in an easier and cheaper mode than by any other means then known. After explaining the different results which are sometimes obtained at trials in the Thames, owing to the velocities of the travelling-wave varying with the depths of the water, the author described the best means of ob- serving the wave on rivers and other like places, and then proceeded to the application of some of the principles before laid down to practice. First, he said it was a delightful circumstance that the wave-principle did not meddle at all with the form of a ship's midship section, but left the conductor entirely free to adopt any form of section he pleased. Next, it did not tie him down to any proportion of depth to breadth. It was, therefore, a plas- tic thing, and could be applied to any general form of ship whatever. The third and most important proposition was, that the wave-line prescribed the exact length of ship for every speed at which you wish a ship to go, and explains why a long ship is indispensable to speed. To go six miles an hour, your vessel must be at least 30 feet long; for eight miles an hour, 50 feet long; for ten miles, 70 feet; for twelve miles, 100 feet; for fifteen, 150; for eighteen, 200 ; for twenty, 300; for twenty -five, 400; and for thirty, 500. The author had himself tried to obtain higher velocities than these with shorter vessels; and he had got them, but at such a fearful waste of power that it was insanity and folly not to lengthen the vessels for the purpose. The wave-line theory also told you that the length of the bow should be to that of the run as 3 to 2. The cause of this was explained. The lines of the Great Eastern, the author said, were neither more nor less than an exact copy of the wave-lines. The length of the bow was 330 feet; the length of the run, 220; and having got this length of entrance and run, and feeling that more capacity was wanted, it was of no use lengthen- ing the bow or the run, because there was already provision for greater speed than the fifteen miles an hour which the poWer to be put into her could be expected to give; 120 feet of parallel body were therefoi-e put into her amid- ships. The great ship might be of less fine-lines and still go with the same velocity. There was a very valuable conclusion for practical ship-builders to be' drawn, independently of what had been stated about the lines. It was this : That proportionate length and breadth were not necessary at all for a fast vessel. It was not necessary for a fast vessel that she should be a narrow, thin, long vessel in proportion to her size. The author had taken vessels on the wave-line principle two hundred feet long, and had them made of every variety of breadth, and as long as they were two hundred feet long, and had 1'ic lines belonging to fifteen or sixteen miles an hour, so long they hud gone 22 AXXUAL OF SCIENTIFIC DISCOVERY. at that velocity with a given power. Further: the resistance which n vessel experiences from the sticking of water to the skin was a most formidable element of her whole resistance; and greater velocity in proportion to power would be got out of a vessel which was shorter than another, and also broader and deeper than another, providing length enough for the velocity aimed at were got at starting. It was the duty of the author, however, to say a word or two on the his- tory of the subject, and the degree of novelty or non-novelty to which it pretended. And he began with saying that he did not claim to be the in- ventor of hollow bows. They had existed as far back as he could trace steam navigation. When he had first discovered what he believed to be the principles of nature which bore on this subject, he felt that the form of ves- sel which accorded with them could not be new, and he set about examining all classes of vessels. He found proofs immediately; so many, that he felt astonished that the books and treatises on naval architecture had not all told them to do nothing but make hollow bows from the beginning. He showed that it must have been impossible for barbarous men to have made a rough boat from two flat planks without forming such a bow. But the old tonnage laws had compelled builders to make ships of the greatest possible capacity compatible with certain measurements. Hence the bluff bow was made a matter of necessity. When, during the wars, we captured Spanish ships or privateers with fine and often hollow lines below, vessels which sailed admirably under their original trim, in which they were down by the stern, we invariably found that they proved but dull sailers in our hands, owing undoubtedly to the fact that we not only overloaded them with weights, but trimmed them nearer to an even keel, and so brought the bluff upper part of their bows down into the water. The boats of the London watermen illustrated the same principle. The author concluded by stating that the rapid advancement of confidence in the wave principle was owing very much to the British Association for the Advancement of Science, which had placed at his disposal large means for the prosecution of scientific researches into this subject, and had every year enabled him to publish to the world the progress which he was making in the investigation. NEW METHOD OF CLEANING THE BOTTOMS OF IRON VESSELS. A new and novel method of cleaning the bottoms of iron vessels has been successfully put in operation by Captain R. P. Dyker, of New York City. The apparatus consists of blocks, each formed of three pieces of cork-wood and one of white-wood, firmly bolted together. On the piece of white- wood are fastened nine knives, or scrapers, six of which run parallel with the line of the vessel, and the remaining three are placed at right angles with the others. Ropes pass through these blocks, which latter may be so arranged as to be of any required length. To lengthen them it is only ne- cessary to shackle on others. The block that comes in contact with the keel is much thicker than the others, so that it may reach that portion of the bottom which the thinner blocks would not. The blocks of course vary with the depth of keel of the vessel which is to be cleaned. The operation of cleaning an iron brig of about two hundred tons is thus described by the New York Cominr-rcutl Advertiser: The apparatus con- sisted of seven blocks, of eighteen inches in length, ten inches wide, and MECHANICS AND USEFUL ARTS. 23 seven inches in thickness; the keel block being just double this size. The blocks were cast overboard, and the rope which was attached to them was passed around the bow and underneath the bottom of the vessel, and by hauling upon the ropes alternately the scraping brought off a large quantity of dirt. Five men were employed in the operation, which seemed quite easy. The pressure of the water kept the blocks close to the vessel's side, while the lightness of the materials added much to the rapidity with which the apparatus performed the work. As rapidly as the part of the vessel on which the apparatus was employed was cleaned, the men moved a few inches aft, until the whole bottom was thoroughly scraped. When the sharp curves of the vessel's lines interfere with the use of the blocks, a peculiar-shaped scraper, fitted to a long pole, is used, and, being floated also by cork, the work is comparatively easy and rapid. BEACHING THE GREAT EASTERN. The operation of cleaning the bottom of the Great Eastern has been per- formed by placing her upon a " gridiron," or framework of timber, on the beach at Mil ford Haven, England. The arrangement of this construction is described as follows in the London Times : The beach, to the distance of five hundred and fifty feet, has been exca- vated and levelled to within a few feet of low-water mark at spring tides, which at high water will give a depth of twenty-five to twenty-seven feet. The beaching-place itself is composed of two " grids," fifty yards distant from each other. Each grid is one hundred and fifty feet long, constructed of forty strong transverse " baulks," or beams, of forty -five, thirty-five, thirty, and twenty -five feet long by thirteen inches square. They are laid down in four lots, ten of each length, with an interval between each beam of three feet. Each baulk of timber is firmly fixed in its place by three iron-shod piles, of from three to four feet long. The longest of these lots is laid nearest amidships, and the rest according to their length, thus tapering off to the stem and stern, so as in some degree to correspond with the beam of that part of the ship that will be immediately above them. Two " dol- phins," thirty feet in height, made of four baulks, each thirteen inches square, firmly clamped and bolted together, strongly supported by back and diagonal struts, have been driven in at about three hundred feet apart. These are for the ship's side to lie against, as well as to act as guides in the actual operation of beaching. One of these dolphins will be just forward of the starboard sponson, and the other near her starboard quarter. These, together with the mooring tackle and other necessary gear, all of which are provided, will keep the vessel in her position. The Great Eastern being six hundred and fifty feet long, it will thus follow that when in position she will be supported for five hundred and fifty feet of her length; viz., three hun- dred on the two grids, and two hundred and fifty on the levelled beach, leaving only fifty feet of her bow and stern projecting beyond the timbers and excavations. The whole structure has been made at the expense of the South Wales Railway Company, and will cost upwards of one thousand pounds. IRON-PLATED SHIPS. The first steel-plated frigate, constructed by the French government, was launched in September last. She is called La Gloire, and is a magnili- 24 ANMV-L OF SCIENTIFIC DISCOVERY. cent vessel, seventy-seven metres long and sixteen metiv< ln.r^o two hun- dred ami fifty by fifty-one feel Lngiish. Her aspect is imposing by tin; severity of her lines and by the mass of her iron cuirass. At the height of 1.8:2 metres barely six feet above the water, she presents a battery of thirty-four guns of the most powerful effect; on the forecastle, two long- range pieces; on the quarter-deck, an iron redoubt to protect her com- mander at his post during the action. The reduced masts and Avide funnel indicate that the vessel is not intended to go to a distance from our ports but that she is made for operations in the seas where henceforward the great differences of European policy will be settled. The frigate has been thrice to sea, and it may now be said that she has gloriously terminated her trials. In calm weather she parts the water without shock, and it may almost be said without foam, showing thereby how perfectly her propor- tions have been conceived. Her speed, measured on a fixed basis of nearly eight kilometres, reached 13-py knots, which is the finest result ever a-er- taincd in a ship-of-war. In a ten hours' trip her average rate was 12 j 3 ^ knots with all her fires lighted, and 11 knots with half her fires. In a rough sea she behaved perfectl}'. She pitches very gently, and rolls with a regu- larity thai leaves nothing to be desired. 3Ioa/u-ur dc la FloLte. THE FASTEST STEA3IBOAT-RUXXIXG OX RECORD. On the 13th of October, the steamboat Daniel Drew made the trip between New York and Albany in six hours and fifty minutes, with five landings and against a head wind. The distance on the Hudson River route between the two places is considered to be one hundred and fifty miles; and if we allow ten minutes for each of the landings, they having to be made on both sides of the river, the actual running time will be six hours, and the aver- age speed twenty-five miles per hour. This is equal to locomotive running, and the fastest ocean steamers, in the calmest weather, do not come within eight miles per hour of this figure. Scientific American. IEOX SHIPS. A congress of the most, eminent ship-builders and naval architects of Great Britain assembled in London, in April, 1800, Sir John Packiiititbn in the chair, for the purpose of discussing different points of interest in their profession. One of the most important topics brought forward was the construction of iron ships, and the following is an abstract of the discussion which took place on the subject. Mr. William Fairbairn stated that he had been en- gaged for a period of forty years in various works connected with iron, and its application for ship-building purposes. About thirty years ago, in con- junction with the Messrs. Laird, of IJirkenhead, he found by numerous ex- periments thai vessels made of iron would be capable of more resistance, lighter, and better calculated for a large cargo, than timber-built vessels. Messrs. Laird and himself then commenced building iron vessels on a large scale, and from 183-1 until 1848 upwards of one hundred first-class ships were produced. When first constructed, iron vessels had many defects; great improvements had since taken place, but much remained to be done. Of late years this class of vessels had been constructed very long, in order to give them fine lines and increase their carrying power; but hitherto this increase of length had been obtained at an expense of the strength of the MECHANICS AND USEFUL ARTS. 25 ship. In many cases the length of iron vessels was eight or nine times that of the beam, and although he did not say that such had yet obtained their maximum, length, yet the mode of construction was capable of much im- provement. He assured them that vessels in a rolling sea, or stranded on a lee-shore, were governed by the same laws of transverse strain as hollow iron beams, like the Britannia tubular bridge; hence a ship could not be lengthened with impunity without adding to its depth or the sectional area of the plates in the middle. An iron ship of the ordinary construction 300 feet long, 4H feet beam, and 26 feet deqp was inadequately designed to resist strains when treated as a simple beam; and a ship was like a sim- ple beam when supported at each end by waves, or when, rising on the crest of a wave, it was supported on the centre with the stem and stern partially suspended. In these positions an iron ship underwent, alternately, a strain of compression and a strain of tension along the whole section of the deck, corresponding with equal strains along the keel. Such a vessel could make a number of voyages at sea, because it was there sustained in a measure by the water; but when driven upon a rock, with its bow and stern suspended, it would break in two, owing to the insufficient mode of constructing the decks. An iron ship of the foregoing dimensions, as usually constructed and tried by the beam formula} W = (a d c -f- /), would be broken asunder if tried with a weight of nine hundred and sixty tons suspended from bow and stern. But if the deck-beams were covered with iron plates throughout the whole length on each side of the hatchway, so as to render the deck area equal to that of the bottom, we should have nearly twice the strength. He next considered the displacement of such a vessel in tons, and found the strength far from satisfactory. When loaded to a depth of eighteen feet, the displace- ment was about one hundred and seventy -seven thousand cubic feet equiv- alent to five thousand tons for the ship and cargo. If we considered this weight uniformly distributed, and compared it with the strength determined, we have a load uniformly distributed of five thousand tons added to that of the breaking weight of the metal in the vessel, which would leave a deficiency of strength equal to one thousand one hundred and sixty tons; so that, if laid high and dry on a rock at the centre, it would break with four-fifths of the load which it carried. These were extreme cases, but ships should be built for them if possible. There had been improvements introduced recently in iron vessels, still they were all too weak in the decks. These, he argued, should be so strengthened as to be equal to the keel, and thus provide a margin of strength for every contingency. He recommended the addition of two longitudinal stringers, running one on each side of the keel; the cov- ering of the cross-bearers of the upper deck with iron stringer plates, thick- est towards the middle; also two cellular rectangular stringers one on each side of the hatchway all running the whole length of the ship. He also argued the importance of using the best quality of metal. No plates should be employed that were incapable of withstanding a tensile strain of twenty tons per square inch. Mr. J. Scott Russell pointed out various improvements which he had carried out, especially with relation to water-tight bulkheads. These were a source of great strength to iron vessels, as they were placed inside the ship; and even if a collision took place, and the ship was cut through, they would save it from sinking. Twelve years ago he built a vessel which might be described as all bulkheads, and entirely divested of frames. Be- lieving that the centre of the vessel required to be essentially strong, he 3 2G ANNUAL OF SCIENTIFIC DISCOVERY. earned a web of iron completely through it, in some cases passing through the bulwarks, and sometimes avoiding them. Mr. Ritchie (surveyor of Lloyd's Register) said he should like to hear something from Mr. Russell on the subject of rivets. Mr. Russell said that was a most important matter in the construction of iron ships. He had recently inspected a vessel returned from a voyage, and found that the heads of at least one thousand rivets were off. How they came off was a mystery to him ; but he gave a very modest rap with a hammer, and one of the rivets dropped out. He had adopted the system of conical riveting, which he found to answer very well, as, when the head was gone, the rivet was perfectly water-tight. Mr. Napier (of Glasgow) observed that he did not approve of the tubular system advocated by Mr. Fairbairn; and it must be remembered that a sta- tionary tubular iron bridge had not to contend with the constant strain of the sea. Many and conflicting opinions prevailed as to the best form of the keel; some were for having it flat, others sharp and perhaps both were right. (Laughter.) For his own part, he did not build a vessel to goon the rocks; but if she were taken there he could not help it. If they could possibly arrive at the absolute breaking power of the sea which an iron vessel would bear, it would be a great discovery. He agreed with Mr. Scott Russell, that it was not in the power of man to build a ship which would be able to bear up against the breaking power which the Royal Charter encoun- tered as the sea went over her broadside. Mr. Fairbairn again addressed the meeting, expressing his opinion that iron ship-building was at present in a transition state. They required to have better and stronger plates ; and if owners would only give a fair price for their vessels, many catastrophes which resulted from the use of bad iron might be averted. ON THE EFFECTS OF VIBRATORY ACTION AND LONG -CONTINUED CHANGES OF LOAD UPON WROUGHT-IRON GIRDERS. In a paper presented by Mr. Fairbairn to the British Association for 1860, the author detailed the results of a set of experiments, having for their object the determining of matters with which the public are intimately con- cerned, viz., the efficacy of girders supporting bridges over which raihvay trains are constantly passing. It is well known that iron, whether in the shape of railway axles or girders, after undergoing for a length of time a continued vibratory or hammering action, assumes a different molecular structure, and, though perfectly efficient in the first instance, becomes brittle, and no longer capable of sustaining the loads to which it may be subjected. Mr. Fairbairn stated that the practical conclusion to which his experiments, so far as they had at present gone, would lead, was, that a railway girder bridge would, irrespective of other causes, last a hundred and fifty years. IMPROVEMENT IN THE STEAM-ENGINE. An improvement in the construction of steam-engines recently devised and patented by Richard Barton, of Troy, N. Y., has for its object, first, to enable a steam-engine having a long cylinder, and consequently a long stroke of piston, to be brought within a comparatively small space; and, second, to enable two complete revolutions of the crank shaft to be pro- MECHANICS AND USEFUL ARTS. 27 duced by the stroke of the piston back and forth. The invention consists in connecting the piston-rod and crank of an engine by means of a system of todies and connecting-rods, applied and arranged in a peculiar manner, whereby the above objects are accomplished, and an engine possessing superior qualities for driving the screw-propeller is obtained. ERICSSON'S CALORIC ENGINE. The applicability of Ericsson's caloric engines for all but a very few of the thousand uses for which power is required, has within the past few years been sufficiently demonstrated, and the introduction and use of them is no longer a matter of experiment. More than five hundred of these engines varying in dimensions of cylinder from 6 to 32 inches are now in suc- cessful operation in different parts of the country. Many of these are employed as domestic motors in pumping water. A large number, chiefly 18-inch c} r linders, are performing a similar office at railway stations. Mr. Tibbard, the General Superintendent of the New York Central Railroad, after having had five of these engines in use at water-stations for several months, reports officially, over his signature as superintendent, that they perform an " incredible" amount of labor " for the small quantity of fuel consumed." One of them, at the Jordan station, he says, performs the labor of four men, at an expense of T 9 6 - of one cent per hour; and one at the Siivana station does the labor of five men, at a cost of eleven cents per day, making a saving of over $120 per month. " We have decided," he says, " to use the engines at all stations where we are compelled to supply locomo- tives by pumping." An engine of the same size at the Newmarket station, on the New Jersey Central Railroad, raises thirty-three thousand gallons of water at the cost of less than nine cents a day, or fifty-three cents for six days, as appears from the certificate of Mr. Overtoil, road-master. For driving printing-presses, the caloric engine has been found equally useful. Fifteen daily newspapers in the United States are now printed by it, and we need not add that a daily paper calls for a motor that is economi- cal, efficient, and in all respects reliable. The engines thus employed are of 18-inch and 24-inch cylinders. Engines of 24-inch and 32-inch cylinders are used in raising grain at rail- way stations, and merchandise in large stores; in pulverizing quartz, split- ting leather, propelling sewing-machines, pulping and hulling coffee, ginning cotton, and crushing sugar-cane. The 24-inch engine has also been successfully applied for ships' uses, in pumping, loading, and discharging cargoes, warping ship, handling the anchor, and for many other purposes now calling for manual labor. Many engines have been sent to Cuba, where they have been successfully applied to various uses. And within a recent period an order has been issued by the governor forbidding the erection of any other kind of engines in the city of Havana, or in any town on the island. It is found that, with every increase of dimension, the power of the engine is more than proportionately increased ; and while the engine has been from time to time enlarged from 6 to 8, 12, 18, 24, and 32-inch cylinder with com- plete practical success, there is no reason to believe that the 48 or 60-inch cylinder will express the limit of available and economical power. It is sufficient to say that this limit is not yet ascertained, and that actual results indicate that it has not been approximated. 28 ANNUAL OF SCIENTIFIC DISCOVERY. Several of the largest machine-shops in the United State? are now engaged in the manufacture of these engines, under licenses from the patentee. Among these we may mention the establishments of I. P. Morris & Co., of Philadelphia; the Newark Machine Co., of Newark, N. J.; Cltite Brothers, of Schenectady, and William Kidd & Co., of Rochester, New York; and Nourse &. Caryl, of Boston. Mr. John B. Kitching has established a general agency for the engine in New York City, where he sells machines of his own manufacture, and those of the manufacture of other licensees. It is but an act of justice to the caloric engine to state that the claims that are made for it of entire safety and great economy seem to be abundantly sustained by competent testimony; and we do not forget that the only com- petent testimony in the case is that of men who have themselves employed the engines, or watched them diligently and intelligently in the actual per- formance of their offices. Such testimony is that of Professor Henry, offi- cially made to the Lighthouse Board, to the practical operation of an 18-inch caloric engine in its application to DaboH's fog whistle, or trumpet. He says: "It [the caloric engine] is very simple in construction, easily put in operation ; . . . easily worked, and not liable to get out of order. . . The quantity of fuel required to supply the necessary amount of motive power is too small to be considered an item of importance. The furnace holds about a peck of coal, and no addition to the fire was made during the time the committee was making the examination, though the engine was constantly in motion for several hours. But the properties which more particularly recommend it for the purpose of signals are, that it offers not the least da^n- ger of explosion, and no water is required for its operation/' LENOIR'S GAS-ENGINE. Considerable interest has been excited during the past year, in Paris, by the exhibition of u working gas-engine, devised by M. Lenoir, a French engineer. The machine in question somewhat resembles an ordinary steam-engine, but its motive power is obtained by the combustion of the ordinary illumi- nating gas, mixed with atmospheric air. In certain proportions, this mix- ture is explosive, as gas-engineers well know. But in Lenoir's machine the detonating proportion of two volumes of gas to one of air is avoided, and the highest combination allowed is one of gas to nine of air. Besides, the two are not brought into contact till they have entered the cylinder, when they are ignited by a spark from a little Ruhmkorff apparatus, and the dila- tation of the gases forces the piston forward with great force. When the piston reaches the end of the cylinder, it is carried back a little way by the momentum of the fly-wheel, opening a valve at the same time, and admit- ting another supply of hydrogen and air, Avhich is ignited by an electric spark, and so the alternate motion is established. The whole machine is simple and beautiful, and the only question as to its utility seems to be the very important one of economy. On this point M. Lenoir states, (1), that the prime cost of his machine is only about half that of a steam-engine of the same power; and, (2), that even in using street gas, at the rate of SI. 60 per thousand feet, the saving of fuel, as compared with the steam-engine, is at least fifty per cent., and that they hope to obtain the non-illuminating gas, which will answer the purpose just as well, at one-sixth of the price mentioned. One disadvantage of the MECHANICS AND USEFUL ARTS. 29 steam-engine is shared by M. Lenoir's, viz., all the heat generated cann .' . be converted into power. If there was nothing to hinder the complete expansion of the gases, the temperature of the expanded gas would be as lo\v as before the combustion; but, after a certain point of dilatation is reached, the expansive force left is not sufficient to move the piston, and the air must then be turned into the waste-pipe, though still very highly heated. On the other hand, there are several advantages claimed. Besides the low prime cost and alleged economy of fuel, there is a great saving from the facility of staiting the machine in an instant certainly a very great advan- tage, considering the loss of time and fuel attendant upon raising steam. Then there is considerable expense involved in stopping a steam-engine, which is obviated here; the combustion in Lenoir's engine being stopped instantaneously by the turning of a button. ON A METHOD OF TESTING THE STRENGTH OF STEAM BOILERS. BY DR. JOULE. The author adverted to the means hitherto adopted for testing boilers. First, That by steam pressure, which gives no certain indication whether strain has not taken place under its influence, so that a boiler so tested may subsequently explode when worked at the same or even a somewhat less degree of pressure. He trusted that this highly reprehensible practice had been wholly abandoned. Second, That by hydraulic pressure obtained by a force-pump, which does not afford an absolutely reliable proof that the boiler has passed the ordeal without injury, and, moreover, requires a special appa- ratus. The plan which had been adopted by the author for two years past, with perfect success, was free from the objections which applied to the above, and is as follows : The boiler is entirely filled with water, then a brisk fire is made in or under it. When the water has thereby been warmed a little, say to 70 or 90 Fahrenheit, the safety-valve is loaded to the pres- sure up to which the boiler is to be tested. Bourdon's or other pressure indicator is then constantly observed; and if the pressure occasioned by the expansion of the water increases continuously up to the testing pressure, without sudden stoppage or diminution, it may be safely inferred that the boiler has stood it without strain or incipient rupture. In the trials made by the author, the pressure rose from zero to sixty-two pounds on the square inch in five minutes. The facility of proving a boiler by this method was so great, that he trusted that owners would be induced to make those periodical tests, without which fatal experience had shown that no boiler should be trusted. Newton's (London) Journal. THE GAUGE OF RAILWAYS. The London Engineer says that experience has demonstrated a narrow gauge to be decidedly superior to a broad gauge for railways. The power required to work them is much less, broad gauge roads requiring engines and carriages of excessive weight. The broad gauge necessitates longer axles, which increase the liability of one wheel to run ahead of the other on the same axle, to which there is a tendency on all roads, and a conse- quent binding of the wheels between the rails. It is perfectly established that the narrow gauge affords sufficient space for the heaviest engines. 3* 30 ANNUAL OF SCIENTIFIC DISCOVERT. THE CONTINUOUS RAIL. Our readers are aware that a continuous or compound rail has been for some years employed on various railways; that it has made an obviously improved, smooth, and easy-riding track, when new, at least, and that it is still largely used on the New York Central and other lines. But the general impression is, that it has not proved remarkably successful, if, indeed, it has not decidedly failed. A very brief review of the history of continuous rails, however, and of the circumstances of American roads, will show that the plan is a decided improvement in every particular; that its first cost, and renewals, and the repairs of the rolling stock carried by it, are much less than in the case of the common rail. The first continuous rail was the common rail split vertically from top to bottom the two nearly equal parts breaking joints with each other, and fastened together with rivets. In case of wheels worn on other and differ- ent sized rails, the whole bearing might come on one of these parts, rapidly crushing it, and prying the two apart. The lamination of the inside edges still further sundered the two bars, and the frost rapidly split them apart, breaking the rivets. This rail was impracticable, although for a few months it made, the best road ever laid. "While it was good, and before it had seri- ously deteriorated, it was believed to have saved enough repair expenses of way and machinery to have nearly paid for its extra cost. The next plan of continuous rail had a split head and a solid foot, half the section of the head resting on the foot of the other half. The abrasion of the iron upon iron, in the absence of rigid connection between them, soon destroyed this rail, but it manifestly decreased the repair expenses of machinery. A suc- cessful continuous rail was then brought out, which had a split foot and a solid head, the small section of the foot forming a sort of continuous splice, or bracket-joint. This has been in service for above six years on the New York Central. It is to be regretted that that company has not kept a more definite record of the influence of the continuous rail on the repair expenses. The obvious results of long practice, however, are such that it is still largely used, and that the manner in which it eases the shocks usual at the joints of common rails, and its uniform elasticity, have made it a decidedly paying investment. But the philosophy of permanent way, as deduced from the general experience, is more conclusive. No one will dispute the fact that the thorough ballasting and drainage of the road-bed will allow the use of such a high rail as can alone be thoroughly spliced at the joints. But this high rail is necessarily rigid, and if not supported by an even bed of ballast and sleepers, will bring its bearing on widely distant parts of the road-bed, since it cannot yield so as to bear on all parts; hence the rail will perma- nently bend and rapidly deteriorate, and, when both rigid and rough, will form the worst imaginable track. The experience with the seven-inch rails on the body-ballasted part of the Camden and Amboy line proves this, while much heavier rails on the English well-ballasted lines outlast light rails on the same road-bed. A light, yielding rail, however, on a mud road-bed, will adapt itself to the churning of the sleepers, and take a bearing on the whole of the bed. It will not permanently set when sprung and twisted, and if it becomes bent on a very bad line, it will not be both rigid and rough, but will be somewhat elastic under the wheels. It appears, then, that we must have either tolerable ballasting and drainage, a good road-bed, or else a shallow and yielding rail. Since our managers are either too limited as to MECHANICS AND USEFUL ARTS. 31 means, or too unwise when they have the means, to institute the funda- mental remedy, the compromise is generally a low rail, which, for the very reason of its shallowness, cannot be spliced at its signally vulnerable point, the joint. So the difficulty engendered by a low rail is almost as serious as that sought to be avoided by the low rail the disconnected joints soon wear and hammer themselves and the machinery to pieces. Now, several hundred rail-joints have been invented, some of which really preserve, to a considerable extent, the continuity of the rails as if they were a continuous bar; but those that do so run into two obstacles, which are nearly fatal: 1. The cost of thoroughly jointing a low rail is too enormous, in the eyes of those who will use low rails, at all to warrant its adoption. 2. The neces- sary weight and rigidity of a good joint are so great as to destroy the very effect sought in the low rail continuous elasticity. Now, the continuous rail is the compromise between these almost irreconcilable elements. It is a continuous splice, not, indeed, preserving the full strength of the bar at the joint, but preventing much deflection, and equalizing what there is; that is, bringing down both rail ends alike. This it does without adding rigidity, for the weight is the same at all parts. The cost of the continuous rail is five dollars a ton over that of the solid rail of equal weight. This makes the joints cost about a dollar each; and we know of no other joint, costing a dollar, which so securely fastens the ends of low rails, for the lower the rail the greater the difficulty in jointing it. New York Times. DO RAILWAY RAILS EVER WEAR OUT ? Mr. Herapath, editor of Herapath's Railway Journal (England), states, on the authority of some of the most practical and experienced railway men of Great Britain, that railway rails, unless at stations and places where there is sliding, do not sensibly wear out. This statement, however, applies to rails made of good iron, not inferior iron tinned over, as it were, with good, and to rails on the middle of a line, over Avhich trains are run in the ordi- nary way. Experiments have been made by taking up and carefully weigh- ing rails in this position after twelve months, wear, or more, which Avere found not sensibly to have lost any weight during that time, thereby proving that there could have been no sensible wear. THE BISSEL LOCOMOTIVE TRUCK. The common locomotive truck consists of a frame, holding the four front Avheels, and turning on a pivot, or king-bolt, like the fore axletrec of a wagon. Although such a truck moves round a curve more easily than if it were rigidly parallel to other shafts and did not turn on its king-bolt, yet its action is "hard, like that of a car whose wheels are nearer together on one side than on the other when moving on a straight track. With the Bissel improvement, the truck does not turn on its own centre, or pivot, but slides sidewise under the engines, being held by a radius-arm extending back under the engine, and fastened to a pin half-way between the centre of the truck and the forward driving-shaft. Thus all the axles of the engine are more nearly radial to whatever curve the train strikes; the wheels are less likely to run off, and move with less friction; shorter curves may be passed, and the flanges wear less. The chief improvement is, however, that one pair of wheels may be used instead of two pairs, which are necessary in the old 32 ANNUAL OF SCIENTIFIC DISCOVERY. truck. Another incidental and considerable advantage is, that with a single shaft the bearing of the engine is thrown further forward, and the weight necessary to adhesion is thrown further back upon the driving-wheels. IMPROVED LOCOMOTIVES. The introduction of cheap steel, and the gradually spreading fact that combined strength and lightness at any reasonable cost will pay at once and handsomely as features of locomotive machinery, are leading to a signal improvement in the locomotive engine. At the Albany Iron Works, semi- steel is being largely introduced for all parts of boilers, allowing twenty-five per cent, increase of strength with the same weight, or twenty-five per cent, decrease of weight with the same strength. It is probable that a higher pressure will be employed, since it is economical in itself, and that boilers will be somewhat lightened. Steel tires of the same make are now under- going a so far promising trial. They will greatly add to the durability of engines, and decrease weight where lightness is most needed in the parts unrelieved by springs, which act as a forge-hammer directly on the rail. The above features cost no more in semi-steel than in iron, and therefore should come into much more rapid use. Krupp's Prussian steel axles the best in the world arc finding favor at double the cost of iron. We do not hear that they ever wear out or break. They have not been in use long enough to show old age yet, though some have run in this country over a dozen years. Another decided improvement in locomotives is in the propor- tions of the boiler and the steam-generating apparatus. Smaller grates, larger combustion room, a very much larger water-circulating space, allow- ing less nominal and more real heating surface, and the modern appa- ratus in the smoke-box for facilitating draft, have considerably decreased the consumption of fuel and the wear of boiler in the production of a given power. THE MANUFACTURE AND DEFECTS OF CAST-IRON CAR- WHEELS AN IMPROVED WHEEL. The supply of car-wheels to railway equipment has become a distinct and extensive branch of the foundry business. Several very large establish- ments, and many smaller ones, are constantly employed in this single manu- facture. Wrought-iron wheels, such as are almost exclusively used in Eu- rope, are too expensive, according to our railway policy a reduction in first cost is the leading considci'ation ; while the flanges of wrought wheels rapidly cut out on our most crooked roads, rendering a harder material desirable. Steel tires, which are, scientifically considered, the best known for durability and shape, roundness, are very much more expensive; and our roads have not yet found it expedient to introduce them. The improvement we shall describe will furnish many of their advantages at a very cheap rate. The service of car- wheels, especially on our rough roads, is very severe; great strength to resist side and other strains, and the incessant hammering of our jointless rails, and extreme hardness of the tread or rolling surface to prevent rapid wear, together with the greatest possible lightness, are essen- tial. To embody these conditions in a single casting is more difficult than the uninitiated would imagine; the nature of the metal itself is in most re- spects adverse to such a result, though in one respect it is extremely favor- MECHANICS AND USEFUL ARTS. 33 able. There are certain kinds of strong, hard iron, which, when melted and suddenly brought in contact with a cold metallic surface, will " chill; " a stratum of the iron about half an inch thick will be converted into white, fine-drained surface, of such extreme hardness that ordinary tiles and drills will make no mark on it. Such iron is poured into moulds, of which the part touching the tread of the wheel is a ring of metal, which chills the sur- face, the rest of the wheel cools more gradually, and is only a little hard- ened, for " chilling iron " always hardens when recast so much so, that new admixtures of pig-iron must be added, or it will become too brittle and " short " for wheels. But the wheel, while cooling, contracts unequally, since the thickness of its parts are different, leaving a severe and permanent strain an inherent tendency to fly to pieces, which the roughing of our roads does not ameliorate. To make a shape, by means of corrugations of innumerable forms and directions, that will allow the parts to yield to this coTitracting force while cooling, so that no strain shall be left in the wheel, has been the subject of hundreds of patents. Again, the "chilling iron" that must be used for the tread is too hard and brittle to answer the best purpose for the rest of the wheel, while the softer and tougher irons that are best to resist strains will not chill; so a single casting cannot fulfil every desirable condition. It has long been the custom of some lines to use chilled cast-iron tires on locomotive driving-wheels. They are much harder than wrought tires, and wear better; they are not so truly round as wrought iron or steel tires, which are turned in a lathe; their adhesion is less, and they are very heavy and hard on the track. Yet they are very much cheaper than wrought iron, not to speak of steel. Considering their immense weight, their economy in the long run is questionable. But this chief objection has been partially ob- viated by Mr. H. W. Moore, of the Union Car-Wheel Works, Jersey City, who has perfected a process of casting the tire hollow, thus reducing the weight of a four and a half feet tire from one thousand pounds to seven hundred and twenty pounds, and at the same time preserving its strength, if not increasing its soundness. All these facts bring us to the consideration of Mr. Moore's improved car- wheel, which is simply a nave or centre-piece of tough, strong cast iron, and a hollow, tire of hard chilling iron. The two, when fastened together by the very simple process used in fastening the same kind of tire to driving- wheels, form a complete cast-iron wheel, which possesses the following very obvious and very important advantages : First, The nave, or centre-plate, never wears out, it being practically a part of the axle. When a common wheel is worn out, the whole of it is used up, and, being all of " chilling iron," cannot be recast into wheels without a large admixture of pig-iron. With the new wheel, the tire only is removed when it wears out. Second, The nave, being subject to no wear whatever, may outlast the axle, and be fitted to new axles as the latter wear out. Third, Tire nave may be made of softer iron than the tread or tire requires, and so be less liable to breakage. Fourth, The tire may be of harder iron than is required for the nave, and so chill deeper and harder, and wear longer. Fifth, The wheel as a whole is stronger, no strain being left in it by the unequal contraction of the metal as it cools. As before mentioned, the great trouble has been that the quickly cooling tire and the thicker and slower cooling hub cause a severe and per- manent rupturing force to be left in the wheel when it is a single casting. In this case, the thin, hollow tire cools without strain, and the nave may bo 31: ANNUAL OF SCIENTIFIC DISCOVERY. easily proportioned so as to cool without strain ; besides, the tire is a hoop and binder in this case, rather than a rupturing force. Sixth, The expense and time required to put on a new tire are less than half what are re- quired to put on a new wheel. The latter process involves taking out the axle, putting it into a press, forcing off the wheel, forcing on a new one by screw or hydraulic power, and replacing the wheel. Putting on a new tire where the wheel is outside of the journal, as on locomotives and some ten- ders and cars, does not necessitate taking out the axle at all; the engine or car is simply jacked up, a few nuts are unscrewed, the old tire is slipped off, and a new one slipped on. Seventh, If the tire breaks, the car has still a wheel to run on, the broad periphery of the centre-plate or nave being left, which is less likely to cause running off the track than a broken solid wheel. Eighth, Not only is the wheel vastly better in every respect than a solid wheel, but the expense of this generally most expensive department of re- pairs is greatly reduced. The price of a common wheel being thirteen dol- lars and fifty cents, the price of the double wheel is sixteen dollars, of which the tire, turned out and furnished with four bolts, costs nine dollars. Two common wheels cost twenty-seven dollars, while the first double wheel and a new tire for the old centre of the double wheel cost twenty-five dollars, saving two dollars on the two sets of wheels. Supposing the old nave to outlast three tires, six dollars and fifty cents are saved; and supposing it to outlast six tires, which is a reasonable supposition, twenty dollars are saved; that is, compared with the cost of six common wheels, the new wheel will have cost nothing, and will have saved six dollars and fifty cents besides. When these figures are applied to the thousands of car-wheels re- newed yearly on our great lines, not to speak of the grand aggregate on all the railways in the country, the -saving promised b} T this improvement is to be represented by millions of dollars. N. Y. Times. ON THE ACTION OF HEAT-DIFFUSERS. The following paper has been communicated to the British Association by Mr. Arthur Taylor: Mr. Williams and others have found that an increased effect was produced by the fuel burnt in steam-boilers when what have been called Heat-Diffus- ers were placed in the tubes or flues. The apparatus in question consists generally of metallic bands or ribands, twisted into spirals, or bent in the direction of their length into zigzag forms, and placed in the tubes or flues, the professed object of this addition being to break up or disturb the current of heated gases passing through the tubes, and to cause every portion of the gases to impinge on the heating surfaces, the cause given for the increased effect produced being, that when a current of heated gases passes through a tube under ordinary circumstances, only the exterior portions of the col- umns come in contact with the sides of the tube, and that in thus disturbing the current by obstacles to its direct coui-se a more perfect contact of the gases with the surfaces is produced. The question which I wish to raise is, whether this is the true explanation of the effect produced by diffusers, deflecting bridges, etc. I think it can hardly be admitted that each mole- cule of a gas passing through a tube follows a course parallel with the axis; for those in contact with the sides of the tube will be so impeded by friction as to have a much slower motion than those in the centre; just as in a river the current near the banks is less rapid than that in the middle of the MECHANICS AND USEFUL ARTS. 35 stream; and that as in the river, so in the tube, a series of eddies will be formed, tending to bring all portions of the gas in contact with the sides of the tube. This peculiar motion of gases in a tube may very clearly be observed in the smoke issuing from the funnel of a steamer, the smoke retaining the eddying motion which it had in the funnel for some time after leaving it. These considerations led me to consider the mere disturbance of the cur- rents as inadequate to explain the increased evaporation observed, and to attribute it to a very different cause. Gases do not radiate the heat which they contain; so that the only mode in which a gas can communicate its heat to a surface is by contact or convection. This is, in the .present practice, the only mode in which those heating surfaces of a boiler which are not exposed to the radiation of the fire, or flame, can abstract heat from the products of combustion ; but if in a flue or tube a solid body be introduced, it will be- come heated by contact with the gases, and will radiate the heat thus received to the sides of the flue. Now these diffusers, etc., exactly fulfil these conditions; and I, therefore, attribute their effect mainly, if not en- tirely, to the function which they must fulfil in absorbing heat from the gases by contact, and then radiating this heat to the sides of the tubes or flues. And I think it will be admitted, that the amount of heat thus con- veyed to the water may be very important, when it is considered that the temperature of the gases in the tubes of a boiler, at five or six inches from the fire-box tube-plates, is about eight hundred degrees Fahrenheit; and that these radiators will consequently have a temperature of several hundred degrees above that of the surfaces in contact with the water in the boiler, and that a very active radiation must consequently take place from one to the other. This principle once established, the modes of application in practice are, of course, endless; and I will only mention that I do not see any advantage in making these radiating surfaces of such a form as to im- pede the draught, especially in the case of marine boilers, but would rather choose the form which would give the greatest amount of radiating surface, and offer the least impediment to the free passage of the products of combustion through the tubes. Perhaps as effective a form as any for placing in the tubes of boilers would be a simple straight band of metal, or a wider band bent in the direction of its breadth at an angle of sixty degrees. In the case of marine boilers, they should be made so as to draw out easily, to enable the tubes to be swept. ON THE COMBUSTION OF WET FUEL. The following is an abstract of a paper read before the American Associa- tion, 1800, by Professor B. Silliman, Jr., " On the Combustion of Wet Fuel in the Furnace devised by Moses Thompson." In all ordinary modes of combustion, it is well known that the use of wet fuel is attended with a very great loss of heat, rendered latent in the conversion of water into steam. As the most perfectly air-dried wood still contains about twenty-five per cent, of water, the term wet fuel might seem appropriate to all fuels but mineral coal and charcoal. But, technically, this term is restricted to sub- stances like peat, and those residual products of the arts, which, like wet tan, begasse, and spent dye-stuffs, contain at least one-half, and often more than" half, their weight of water. Until a recent period, the attempt to consume these products as sources of heat has been attended with uneconomical results, 36 ANNUAL OF SCIENTIFIC DISCOVERY. or total failure. It is the object of this paper to describe a mode of combus- tion, in which, by a modification in the form of furnace, the combustion of wet fuel is not only rendered consistent with the best economical results, but which involves chemical reactions never before, it is believed, successfully applied for such purposes, and which is deserving of particular notice from a scientific as well as from a practical point of view. It is a well-established fact in chemistry, that the affinity of carbon for oxygen at high temperatures is so strong, that if oxygen is not present in a free state, any compound containing oxygen, which happens to be present, is decomposed, in order to satisfy this affinity. This fact is well illustrated in the familiar case of the blast-furnace, where this affinit}^ is employed to deprive the ores of iron of their oxygen in the process of reduction to metallic iron. In the first stages of combustion, in wet fuels, the chief products given off are steam from the drying of the wet mass, smoke, or volatilized carbon, and oxide of carbon, with, of course, a variable proportion of carbonic acid and carburetted hydrogen. These products, in all ordinary furnaces, pass on together into the stack, carrying with them the heat which they have ab- sorbed and rendered latent. The problem presented is then to recover the heat thus locked up and lost; and by the furnace now under consideration this is accomplished by shutting off almost entirely the access of the outer air, and causing the wet fuel to supply its own supporter of combustion, drawn from the decomposition of the vapor of water at a high temperature, by its reaction with free carbon and the oxide of carbon. The practical solution of this problem was first, successfully accomplished, as appears from a decision of Patent Commissioner Holt, by the late Moses Thompson, in 1854. The controversial questions growing out of this inven- tion are entirely foreign to our present purpose, and in no way affect its prac- tical or scientific value. Suffice it to say, in passing, that we find in this invention another instance of a truth already so often signalized in the history of inventions, that important results are often obtained, of the high- est value in promoting material prosperity and the welfare of society, by those who are guided in their search only by the result in view, and not by any exact knowledge of the scientific principles involved. Mr. Thompson seems to have been inspired with the conviction that if he could bring the products from the combustion of wet fuel together in a place hot enough for the purpose, and from which the atmospheric air was ex- cluded, they would, as he expresses it in his patent, mutually " consume each other." This notion was realized, and the reaction secured between the elements of water and the carbon of smoke, or the oxide of carbon, in a part of the furnace called by the inventor the mixing-chamber. Wherever that place may be situated, or however constructed, the one essential thing about it is, that it should be a very hot place, and one to which the atmospheric air can have no direct access until it has passed by and through the burning fuel. It is, in fact, a retort, or place for combina- tion and reaction, and may be a distinct chamber or flue, or only a recess or enlargement, greater or less, of the main furnace. Wherever it may be placed, or however built, it must meet the essential conditions of a high temperature, and of atmospheric isolation. In this mixing chamber, then, the important chemical reaction before insisted on must be set up. The vapor of water is decomposed, furnishing its oxygen to the highly heated carbon to form carbonic acid, while the oxide of carbon is in like manner MECHANICS AND USEFUL ARTS. 37 exalted to the same condition, and any excess of carbon forms, with free hydrogen, marsh gas, or light carburetted hydrogen. The vapor of water is thus made to give up not only its constituent elements to form new com- pounds with oxygen, producing in the change great heat, but a great part of the heat absorbed by the water in becoming steam is also liberated in this change of its physical and chemical condition. Moreover, as all these products of combustion and of chemical reaction pass together over the bridge-wall of the furnace into a space from which atmospheric air is not excluded, it then and there happens that any free hydrogen, light carbu- retted hydrogen, or oxide of carbon which have previously escaped com- bustion, take fire and burn, yielding up their quota of heat to the general aggregate. Such is the intensity of heat in that portion of the furnace where these reactions take place, that only the most solid structures of refractory fire- bricks will endure it, and the color seen throughout that portion of the furnace is o'f the purest white. In view of the facts already stated, it is easy to understand why it is that when the reactions described are once set up, the admission of a free current of atmospheric air should immediately check the energy of the combustion, and soon result in total suspension of the peculiar energy of this furnace. The air containing only one-fifth of its bulk of oxygen gas, the active agent in combustion, the access of so large a proportion of cold air, four-fifths of which are not only indifferent, but positively prejudicial, from the quantity of heat it absorbs, it happens that the temperature of the mixing-chamber is rapidly reduced below the point at which carbon can decompose vapor of water, and the instant that point is reached the arrival of fresh supplies of steam completes the decline of energy, and the furnace commences forth- with to belch forth from its stack dense volumes of smoke and watery vapor. When in proper action, not a particle of smoke is visible from the stack of a furnace in which wet fuel is burning, and, what is more remark- able, the reactions are so evenly balanced that no wreaths of watery vapor are observed; while, in the earlier stages of combustion, before the proper temperature in the mixing-chamber is reached, both these products are seen in great abundance. The language of the inventor, in describing the construction of his furnace for burning begasse, is as follows : " I build two furnaces, side by side, each nearly square in its horizontal section. Towards the top I draw in the wall in such a manner as to form a kind of dome, with a sufficient opening at the top to feed the begasse. In each furnace-chamber there should be a partition of fire-brick, extending across it from front to back, and rising nearly to the top, dividing it into two nearly equal parts. The main chamber of each furnace should be divided into two parts, upper and lower, by a fire-brick grating about one- fifth the height of the furnace above the hearth, the back end of the grate being a little lower than the front. "In each furnace, at the front, on each side of the central partition, and immediately under the front end of the grate, should be doors for feeding wood and other dry fuel, and directly under these doors, at the hearth of the lower chamber, should be draught openings, capable of adjustment, to sup- port combustion in the lower chamber. Extending across the back of both furnaces, and opening into both by flues, is a mixing-chamber, into which all the gases from both furnaces enter in a highly heated state, and mix and 4 38 ANNUAL OF SCIENTIFIC DISCOVERY. consume each other on their way to the boiler and stack. This chamber should be about one-half the capacity of all the fire-chambers, and it should extend down about as low as the back end of the grate. The flue through which the products of combustion pass out of this chamber and under the boiler should be in section about one square foot to forty cubic feet of mixing-chamber. " The operation of my furnace is as follows: A hot fire of dry fuel is kin- dled in the lower or fire-chambers of the furnaces, and after it has been con- tinued till the masonry is well heated, the chamber above the grate is fed with the begasse or other wet fuel. This hot fire in the tire-chamber, especially towards the front of it, under the principal mass of the wet fuel, must be preserved throughout the operation. The heat from the masonry and the fire-chamber will be communicated to the wet fuel, which will cause steam and other gases to issue from it and mix with the intensely hot gases of combustion from the fire-chamber, and in a short time the mixing-chamber will present intense combustion and heat, the dampers of the fire-chambers being partially closed. The lower part of the wet charge will by degrees become dry and charred, and will fall through the grate prepared as above into the fire-chamber, and supply, or nearly supply, the place of other dry fuel in preserving the fire in this chamber; and the wet fuel, being from time to time supplied, will furnish, in a highly heated state, aqueous vapors, which, descending through the corrugations and otherwise into the fire- chamber and mixing-chamber, will be decomposed, furnishing much oxygen to the fire, and supply the oxygen necessary to combustion of all the com- bustible gases issuing from the fire-chamber. If by accident the fire in the lower part of the furnace should predominate, the draught should be dimin- ished and more wet fuel added; and if by accident the fire in the fire-cham- ber should become too much cooled down, the draught should be let on, and any deficiency of dry fuel should be supplied to the fire-chamber. Under proper management, little or no dry fuel need be fed to the fire- chamber after the operation is fairly commenced the charred matter falling through the open grate will supply its place; and the caloric thus produced by the combustion of wet fuel will be vastly greater than from the same quantity by measure of the same fuel when dry. In the fire- chamber and in the mixing-chamber, under intense heat, the carbonaceous gases will decompose the steam from the wet fuel, and effect complete com- bustion. " When the operation is fairly commenced, if the water in the wet charge amounts to say fifty per cent, by weight of the fuel, the dampers of the fire- chamber should be nearly or quite closed to exclude the air; vapor from the wet charge will then descend through the corrugations and otherwise into the fire-chambers, and support the combustion therein, while other portions of the vapor will enter the mixing-chamber, and complete the combustion there. If the fuel, however, contains much smaller quantities of water, more air in proportion should be admitted at the damper, the object being to admit no more air than will supply the deficiency of the vapor." It will be observed that in this mode of combustion the wet fuel is subject to a constant process of distillation by the fire in the ash-pit. The products of this distillation react on each other in the mixing-chamber in the manner already described, while, at the same time, a portion of watery vapor is decomposed in the ash-pit. Theoretically, no more heat can be generated in this mode of combustion MECHANICS AND USEFUL ARTS. 39 than is consumed in the transformation of water into steam, and the conver- sion of fixed into volatile products. But it is by no means a matter of indif- ference whether the oxygen requisite for complete combustion is drawn from the atmosphere or is derived from the decomposition of water by car- hon and its oxide. In the former case, not only is there a great loss of heat, carried away by the inefficient nitrogen of the air, but the diluted oxygen can never produce so intense a heat with the carbon as is the result of the reaction of the nascent oxygen with that element. Although Mr. Thomp- son was no chemist, he did not fail, with his natural acumen, to perceive this advantage; and in his earliest patent he remarks: "After ample experi- ments, I have discovered that any results that can be produced by the use of dry fuel are inferior to those obtained from my process in proportion to the quantity used, and that results like mine can only be obtained by the use of wet fuel . . . fed into an intensely heated chamber. Under such cir- cumstances, the water in the fuel, in presence of the carbonaceous sub- stances in the furnace, will be decomposed, giving its oxygen to the carbo- naceous matter, dispensing with a draft and its cooling and wasteful influence, and rendering the combustion so perfect that no smoke is visible." Although this mode of combustion of wet fuel is now in use on many sugar plantations in Louisiana, and in some tanneries of Pennsylvania and New York, no notice of it has, so far as I am aware, appeared in the scien- tific journals. I am not without personal experience of its operation on a large scale, having, in 18o7, enjoyed the opportunity of studying carefully the management of one of Thompson's furnaces, in three compartments, built for the combustion of wet peat. That fuel contained over seventy -five per cent, of its whole weight of water, and was too wet for the best results. But with the use of one fourth part of dry wood, even this extremely wet and otherwise valueless fuel was rendered efficient, three cords of one hundred and twenty-eight cubic feet of wet peat, and one cord of dry wood, doing the work of four cords of dry wood in driving a steam boiler. FRICTIOXAL GEARING. Frictional gearing is coming into successful use in Great Britain for all purposes, from small machinery up to the driving of the screws of steam- ships. Instead of one wheel driving another by the intersection or "mash- ing" of the " cogs" or teeth on their rims, the adjacent surfaces or faces of the wheels are grooved lengthwise, or in the direction of their motion, like the rolls of a rolling-mill. These grooves are V-shaped, and the friction of the Vs of one wheel against the sides of the V's of the other wheel is so great that the one drives the other, as in the case of cogs. The friction of the journals of the shafts is somewhat greater than in the case of toothed gear- ing, but in other respects the frictional wheels seem to work most smoothly. The " back lash," or rattle of teeth, especially when worn, is prevented. The chief economy is in first cost. The cutting of the teeth of gearing involves the application of abstruse mathematical principles; each side of each tooth is shaped to an epicycloidal curve, varying with the diameters of the wheels. The machines and processes required are expensive and numer- ous, especially in cases of beveled gearing. But the preparation of frictional gearing is the most simple and straightforward work of the turning-lathe. 40 ANNUAL OF SCIENTIFIC DISCOVERY. LARGE IRON FORGING S. Mr. R. Mallet has read to the London Institution of Civil Engineers a paper "On the Coefficients of Elasticity and of Rupture in "Wrought Iron, in relation to the volume of the metallic mass, its metallurgic treatment, and the axial direction of its constituent crystals." Iron was formerly entirely worked under tilt-hammers; the process of rolling was then introduced; and now, in consequence of modern engineer- ing requirements, masses of iron, ot considerable magnitude, were produced by faggoting- together, under heavy forge-hammers, from large numbers either of bars or slabs grouped together. The masses were not, however, found to possess ultimate strength in proportion to the number of bars of which they were composed; in fact, it appeared that the strength of the mass became less in some proportion as the bulk became greater. This was admitted as a fact, but no one had hitherto attempted to show experimen- tally what function of the magnitude was the strength of a given kind of iron, manufactured in a given manner; or how the same forged mass, when very large, differed in strength in different directions, with reference to its form; or how the mechanical part of the process of manufacture of the same iron affected its actual strength, either as a rolled bar or as a forged mass. Addressing himself to this investigation, the author dealt generally with three points of the inquiry, viz. : 1. What difference did the same large bars of unwrought iron afford to forces of tension and of compression, when prepared by rolling, or by ham- mering under the steam-hammer? 2. How much weaker, per unit of section, was the iron of very massive hammer forgings, than the original iron bars of which the mass was com- posed? 3. What was the average, or safe, measure of strength, per unit of sec- tion, of the iron composing such very massive forgings, as compared with the acknowledged mean strength of good British bar iron ? We have not space for the illustrative details, but the conclusions deduced were, that practically the iron of very heavy shafts, forged guns, huge cranks, and other similar masses, might be expected to become permanently set and crippled at a trifle above seven tons per square inch, and to give way by fracture at about fifteen tons per square inch by tension, and to completely lose form at pressures of from fifteen to eighteen tons per square inch. Therefore it followed that, allowing a deduction of one-half, as sanc- tioned by practice, from the elastic limits of tension and of pressure, for the margin of safety, the iron of such forged masses should not be trusted for impulsive strains exceeding about one and three-fourths tons per square inch of tension, and about four and a half tons per square inch of pressure, or for passive tensile strains of three and a half tons per square inch, or for passive pressure beyond nine tons per square inch., THIN CAST IRON. At a recent meeting of the Manchester Philosophical Society, Mr. Fair- barn, the President, exhibited two large pans of cast iron, procured from China, where they are used for boiling rice. The metal, which is at the strongest part only one-tenth of an inch in thickness possessed considerable MECHANICS AND USEFUL ARTS. 41 malleability. The President remarked that the art of making such large castings of thin metal was unknown in England. STRENGTH OF GUN-METAL. " We were never so powerfully impressed," says the Liverpool Albion, "with the improvements in the manufacture of gun-metal, as during a recent visit to the Mersey Steel and Iron Works, where we witnessed various attempts to burst a two-pounder gun. The experiments took place in a chamber excavated in the sandstone rock, covered over with loose sheets of iron, which, of course, made a considerable rattle when each explosion took place. The gun in question, which is five feet two inches in the bore, and weighs somewhere about four hundred pounds, after being charged with one pound of powder, was filled to the muzzle with one-pound balls, and fired by means of a string. When the smoke had cleared away, it was found that the gun was all right, and that so great had been the force of the ex- plosion that many of the shot were shattered, and others deeply buried in the rock. The gun was again charged, and filled with balls, and a cylinder, or round bar of iron, which projected from the mouth. It was then fired, with equally satisfactory results. The next trial was with one and a half pounds of powder and three cylinders, weighing seventy-six pounds all to- gether. This is a test which few guns are calculated to withstand; but, though the noise of the explosion was very great, the metal of the gun was so tough that it remained uninjured. The weight of the metal was after- wards gradually increased to nearly ninety pounds, Avith safety. EXPERIMENTS WITH CAST IRON. A series of interesting experiments has recently been carried on, under the managemeat of Colonel Eardley Wilmot, Superintendent of the Royal Gun Factories at Woolwich, England, with a view to determine the most suita- ble variety of iron for casting cannon ; and the results have been printed in the form of a parliamentary report. Information regarding the several brands of iron experimented with would be of little interest to our readers, but there is other information in it interesting to all those who work in cast iron, and the substance of this we give, as follows : The general mean tensile strength of 8-30 specimens of cast iron was 23,257 pounds on the inch ; the transverse strength of 564 specimens was 7,102; while the crushing strength of 273 specimens was 91,001 pounds, and the torsion but 0,0-30. It was found, during these experiments, that when the specific gravity of cast iron was 7'3, and upwards, it was too hard, and did not possess suffi- cient elasticity for casting cannon. A marked superiority was the result in bars cast horizontally over those cast vertically. Bars which were cooled quickly were also much stronger than others cooled slowly. It was also found that, by repeated re-melting of the cast iron, its quality was greatly improved. This etfect, however, was not so marked when large masses of several tons were operated upon at once. It is believed that by re-melting, although such impurities as phosphorus, sulphur, and silica, may not be expelled, some of the graphite in the iron is converted into combined carbon, which enables the contraction and crystallization of the metal to be more complete. But if the melted iron is allowed to cool very slowly, the carbon, it is thought bv some, is reconverted into graphite, 4*' 42 ANNUAL OF SCIENTIFIC DISCOVERY. and the iron becomes soft. Repeated melting, then quick cooling, and hori- zontal casting, greatly improve cannon, and all articles made of cast iron. HOVT THE ARMSTRONG GUN IS MANUFACTURED. A visitor to the works, who has never seen an Armstrong gnn, must, as he witnesses the successive stages of its manufacture, be sorely puzzled to conceive what it will look like when completed; and scarcely less is the surprise of any one who has seen the finished piece, at the strange shapes which its component parts assume during the various processes. Let us begin at the beginning, and observe the various steps, from first to last, in the creation of the most perfect piece of ordnance the world has ever seen. Imagine a very long, thin bar of the finest iron, some two inches square, and one hundred and twenty feet in length that is the basis of a twenty- five-pounder. For convenience in the manufacture, this bore is divided into three pieces, about forty feet in length. A hundred-pounder requires three pieces, each of ninety feet in length. The manufacture commences in the forging shop, a vast, dingy shed, where there is an incessant din of hammers and roaring of mighty furnaces, where blocks and bars of iron lie scattered in seeming confusion on every side here almost transparent at white-heat, there glowing red-hot; in one corner sending out showers of sparks under the discipline of a huge steam-hammer, in another hissing and sputtering under a stream ; where stalwart, grimmy men, with uprollcd shirt-sleeves, visors, and leather aprons, are seen looming through the smoke, or, in the full glare of the fires, tossing about red-hot bars with the indifference of salamanders, and making the anvils ring with thirty-Cyclops power. "We fix our eyes on a long narrow furnace, in which lie a number of the iron bars we spoke of. Suddenly the door is opened, and a fierce lurid gleam of light is cast through the shop. One of the men seizes the end of a bar in a pair of pincers, drags it forth, and makes it fast to a roller which stands immediately before the furnace, and the diameter of which is equal to the rough-made tube of a twenty-five-pounder when first rolled. The roller is put in motion the bar is slowly and closely wound around it, just as one might wind a piece of thread round a reel. The roller being turned on one end, the spiral tube Xo. one coil it is termed is knocked off, restored to white-heat in another furnace, for it has cooled somewhat in the rolling, and then flattened down and welded under one of the steam-hammers, till only about half as long as it was. For a twenty -five-pounder, the length of the coil after this process is two and a half feet; and three such coils are welded together to form the tube. Before that operation is performed, however, each coil is bored in the inside, and pared on the outside, to within a very little of its proper diame- ter, so that the slightest flaw in the welding, if any exist, may be detected. Having passed this test, a couple of coils, brought to a proper heat by being placed end to end in a jet of flame from a blast-furnace, are welded by violent blows from a huge iron battering-ram. A third coil is added to the other two in the same manner, and the tube is complete. Over this a second tube, which has been prepared just in the same way, is passed while red-hot, and, shrinking as it cools, becomes tightly fastened. This is termed " shrink- ing on." Over this again is placed a short, massive ring of forged iron, to which the trunnions or handles of the gun arc attached. MECHANICS AND USEFUL ARTS. 43 The breech, which has now to be added, is composed of several iron slabs, something like the staves of a barrel, which are bent into a cylindrical form, and welded at the edges, when red-hot, under the steam-hammer. In the breech, the fibre of the metal runs in the direction of the length of the gun, while in the other parts it winds round and round trans versely. This is done to give greater strength to the breech in sustaining the whole back- ward thrust of the explosion. The breech thus formed is "shrunk on" to the rest of the gun; and to add still more to its strength, two double coils of wrought iron are rolled on with the fibre at right angles to that of the breech underneath. The piece now exhibits very much the appearance of what is called a three-draw telescope the tube, the trunnion-piece, and the breech representing the three " draws" of the glass when pulled out. So much for the rough work of the gun; AVC now come to the finer and more delicate process. Having been pared clown on the outside to its proper size, the gun passes to the measurers, who, with an instrument called a micrometer, measure each part with mathematical accuracy. The slightest deviation of any portion from its exact size, even to the fraction of a hair's breadth, is rigidly pointed out, and has to be amended. The boring and rifling of the piece are next performed, in a large, tidy, well-lighted room, where there is no noise, or smoke, or confusion, as in the forging shop. The gun is placed erect in the boring-machine, and revolves gently round the big gimlet, which slowly but surely wends its way downwards, scooping out the superfluous metal from the interior of the tube. Four pieces can be bored at once by each machine. This is the lengthiest process the gun lias to go through. It has to be performed twice, each time occupying six hours. First, the gun is bored to within a -j-oV 00 yards ; and out of three shots fired, two fell precisely on two parallel lines, within six feet of one another. The experiments with the twelve-pounder were equally remarkable. At twenty degrees of elevation it ranged from 6,818 to 6,339 yards; at five degrees of elevation, it averaged 2,300, and threw all its shot within two and a half yards of the true line of fire. Perhaps the most beautiful part of the performance was that in which Mr. Whitworth showed how capitally his bolts could be made to rico- chet. The spectators were ranged on the sandy ridges about a hundred yards from the shore. More than a mile and a half away might be descried a little group gathered around the guns; presently came a flash, then an interval of a few seconds, then the rumble of the report, and almost at the same time the sand in front was ploughed up and dashed away right and left, and the bolt might be heard rushing high overhead with a sort of w r ild scream, and presently marking the spot of its final fall by a tiny splash in the far distance. Subsequent trials at Southport, with three, twelve, and eighty-pounders, according to the Times, surpassed the most sanguine expectations. "The accuracy of fire," it says, " and length of range obtained from trifling charges of powder were so totally beyond what has eyer yet been attained, that it is evident we are upon the eve of another revolution in all relating to scientific gunnery, and that even the greatest results which have ever been obtained from the Armstrong gun are likely to be in turn surpassed by Mr. Whit- worth's ordnance." In the firing with the twelve-pounder field-gun, the range was marked out by tall thin poles placed 1000 yards apart for a total distance of 10,000 yards (about six miles), having short sticks placed in the road at every hundred yards between the chief poles. AYith a twelve-pounder, no experiments hav- ing been made expressly to test the range, a six-feet target with a two-feet bull's-eye was hoisted at 1000 yards, to show the accuracy of its fire. Two shots were allowed to lay the gun and find the range, the second of which passed between the target and the pole which held it. Of the eight which were then fired, all went through the target within a space of four feet square, and two through the bull's-eye, which, from the place where the gun was fired, looked scarcely bigger than a man's hand. In this result there was nothing astonishing to those who have seen the Armstrong fired, or even the very best practice made now and then with smooth-bored field artillery. MECHANICS AND USEFUL ARTS. 47 The charge was twenty-eight ounces of powder, the service charge for an orclinaiy gun of the same calibre being fifty-six ounces. With the twenty- eight ounces, however, the force and velocity of the shot seemed enormous ; the flight was low, the ricochet very great, and nearly always to the right, in the direction of the pitch of the riding. One shot, after passing through the target, first grazed the sand at 2,200 yards, then again at 3000, after which it went on ricochetting along the shore, touching it every 200 or 300 yards, until it buried itself 5600 yards from the place where it was discharged; the elevation of the gun was I 1 28, at which the recoil was very little, the explosion much less than that of an ordinary field-piece, and the noise occasioned by the flight of the shot comparatively very slight. One man served the gun with the utmost ease, withdrawing with screw nippers the tin cartridge-case from the breech after each shot. The length of Whit- worth's twelve-pounder is about six feet, its bore nearly three inches, and the pitch or turn of the rifling the same as that of all his light guns, one com- plete turn in forty inches; or, roughly speaking, the shot makes nearly two complete revolutions on its axis before it leaves the gun. The bore of the three-pounder is about three and a half inches diameter. Practice with this three-pounder commenced with ten degrees elevation at 4000 } r ards, the charge being only seven and a half ounces of powder. The working features of the gun were the same as we have noticed in the twelve-pounder, except that one man worked the gun with much greater ease, firing it, without the least attempt at hurry, four times in less than four minutes. The sound of the projectile also was scarcely audible. The elevation was then altered to twenty degrees, the same charge of seven and a half ounces being continued for the range of posts, from 0000 to 7000 yards distant. The first shot at this tremendous range struck the sand at 6,760 yards, and only five yards to the left of the true line. The second struck at 6,784, and twelve yards from the true line in the same direction. The third, at 6,720, was sixteen yards out of the line. This deviation to the left was contrary to the usual deviation of the gun, and arose from a rather strong wind which had set in from the sea. The gun was therefore laid more to the right, and threw a fourth shot 6,910 yards distance, and only two yards to the left of the true line ! The charge of powder was then increased to eight ounces, and the elevation of the gun raised to thirty-five degrees. The practice then made was really extraordinary. The first shot alighted in the sand at 8,970 yards' distance, only twenty-two yards to the right of the line. The second fell at 8,930 yards, and only ten yards left of the line; the third, 9,059 yards, ten yards to the right; and the fourth at the immense range of 9,164 yards, and twenty-two yards to the right. Midway between the guns and the target the flight of the projectiles over head could just be heard, and no more. The eighty-pounder was then loaded at five degrees elevation, with twelve pounds of powder, with which .charge it threw a ninety-pound projectile, with a fearful roar, a distance of 2,550 yards, when it ricochetted at right angles and buried itself in the sea at an immense distance. A second shot, with the same charge, first grazed the sand 2,620 yards distant from the gun, and only two to the fight of the true line. From this point it glanced upwards, but continued a straight course onward, alighting in the sand at a distance of over 6000 yards from the gun. Had this piece been mounted so as to permit of its being fired at a high degree of elevation, there is not the least doubt but that it would have thrown its ponderous shot a distance 48 ANNUAL OF SCIENTIFIC DISCOVERY. of 8000 or 10,000 yards, a distance that has never .yet been gained by any gun with a projectile of such weight. WHITWORTH'S AND ARMSTRONG'S GUNS COMPARED. The following interesting comparison of the two new guns, Whitworth's and Armstrong's, and reflections on the effect of their general introduction on modern warfare, are derived from the London Army and Navy Gazette: If artillery be still in its infancy, it is difficult to determine who are to be its nurses, or under what system of education the tremendous giant is to be brought up. It is obvious, from the recent experiments with Armstrong's and Whitworth's guns, that the attempt made to establish a superiority of range and accuiacy on the side of infantry provided with arms of precision over field-artillery, has been unsuccessful; and that the cannon relying on weight of metal can overpower, as before, its ancient enemy, and bids fair to withstand the deadly foes, which hitherto Avere irresistible against unaided artillery, namely, cavalry charge and dash of infantry. But these advan- tages are accompanied by certain conditions which almost amount to defects. There is great increase of expense; there is the necessity of special ammuni- tion, being carried in a special way; there is the loss of accuracy in ricochet fire; there is the diminution of power in discharging grape, shrapnel, and common case with effect; and there is the nicety of mechanism, in addition to the requirement, on the part of the gunners, of a certain skill over and above that necessary to handle ordinary field artillery or guns of posi- tion. As between Mr. Whitworth and Sir William Armstrong, the case stands thus, so far as we know: Mr. Whitworth has invented a gun which throws its shot further than any engine of war has ever yet been able to force projectiles. Sir W. Armstrong has invented, or adapted, a gun which throws shells and shot with greater precision, and at the same time to a greater range, than any other cannon in the world. "We believe, at least, there is no tube, whether it be that of the French rifled gun, or the United States cannon, which combines long range and extraordinary accuracy in the discharge of shell and shot, to such an extent. It will be observed, then, that Mr. Whit- worth excels in range and shot, and Sir William Armstrong is unrivalled in the pi-opulsion of shot and shell, the latter being the more terrible weapon of the two. Mr. "Whitworth, however, is content to do one thing at a time. With a three-pounder of thirty-five degrees elevation, and eight ounces of powder, he throws a bolt, which defies gravity and resistance, for five and a half miles, and falls deep into the earth at the end of its flight. That is a great result; and it is evident, if the number of those small pieces were very great, and the object sought to be hit were a stationary mass, they would produce destructive effects. But, as against stone-works, or even earth- works, these small bolts would make little more impression than arrows fired into an archery butt. It is the heavy concussion of large shot fired at low elevations, and with comparatively small charges of powder, which generally produces the most destructive effects on masonry; whilst on riveted earthen ramparts and gabionades no missile is so efficacious as shells bursting continu- ously in the face of the rivetments. If Mr. Whitworth appeals to his great range alone, we must meet him frankly, and, with the fullest recognition of his great merits and of his very extraordinary achievements, we tell him that, in our opinion, great range of light shot at hiirh elevation is not so formidable by any means as sure practice of heavier shot and shell at much MECHANICS AND USEFUL AIITS. 40 shorter distance. With considerable diffidence, also, we beg to point out to Mr. Whitworth two difficulties against which he must bring his mechanical genius and his indefatigable resolution to bear: One is, the large allowance to be made by the gunners for the influence of strong side-winds on his bolts; the other, and a serious one, the great deflection which occurs in the ricochet after the first graze. Artillerymen will understand how very impor- tant it is that richochet should be as much as possible in the true line of fire. It is our conviction that the importance of very long range from guns at high elevation has been very much exaggerated, if the range be obtained by long bolts, and not by shell. Reason about it as mechanics, philosophers, or metaphysicians may, there is some strange repugnance, if not inability, in man to direct implements of destruction against unseen foes. But it is said we must fit our new guns with telescopes. The experiment would be still unsuccessful. If any one doubts it, let him walk to some hill five miles away from a great city, with a good glass in his hand, and select some point for attack. Then let him examine his own sensations, and ascertain whether he would have much confidence in his three-pounder bolt, and would work his imaginary guns with energy against the mark, and he may rest assured that he has at that moment a pretty certain index to the state of his feelings in actual warfare. Until Mr. Whitworth has proved the adaptability of his guns for firing shell, and the power of his larger ordnance to obtain consid- erable range at low elevations, he may consider that his beautiful principle has not received its full practical development for pui-poses of warfare; whilst Sir William Armstrong must admit that, as yet, his worthy and liberal rival has beaten him in the matter of range, which is one that must always have most important relations to the power of artillery. Mr. Whitworth has proved that his heavy gun throws a shot which maintains its initial velocity for a great length of time, and we doubt not he will yet get great propoi'- lionate range from his eighty-pounder. His lineal accuracy is very great at the lower trajectories of the light guns, and it will, of course, be exceeded by the heavy ordnance. NEW WAR IMPLEMENTS. Hotchkiss's New Projectile. A new form of projectile for rifled cannon has been brought out during the past year by Messrs, llotchkiss, of Connecticut, and has received favorable attention from the United States AVar Department. It is made in three parts : the main body of cast iron, with a space or cavity around its centre, into which a belt or jacket of lead, or other soft metal, is cast. On the rear end they place a cap of cast iron, with the front edge sharp like a wedge, which is driven on to the rear end of the shot, and into the belt or jacket of lead. In this condition the shot is introduced into any rifled cannon of suitable bore, and the action of the powder, when the explosion occurs, forces the wedging cap further into and underneath the lead belt, and expands it into the grooves of the gun. This expansion is not allowed to take place except to an extent barely sufficient to tightly fill the grooves of the gun the extent being perfectly controlled by the depth of the cap, the intei'ior of which drives against the end of the cast-iron body of the shot, and this limits the strain on the gun. The advantages claimed for the shot, are: extraordinary accuracy ; long ranges, with low elevation; light charges of powder, in proportion to the weight of projectile; and immense power of penetration. 5 50 ANNUAL OF SCIENTIFIC DISCOVERY. Monster Gun. One of the largest cannon ever constructed has been cast during the past year at the Fort Pitt Foundry, Pitsburg, under the super- intendence of Lieut. Rodman, of the Ordnance Department. It was cast hollow, upon a core, through which a stream of cold Avater was constantly passing, at the rate of about forty gallons per minute : the object being to produce metal of uniform texture, from the equal cooling and contraction of the mass. The core-barrel, Avhich formed the bore of the gun, was removed twenty-four hours after casting, and water, at the same rate as before, was caused to circulate through the cavity, descending along a tube to the bottom of the bore, rising up by another tube, and escaping through a wrought-ii'on pipe, cast into the spruehead of the gun about fifteen inches from the casting. The metal was entirely cold at the end of seven clays after casting, a shorter time than is required for cooling an eight-inch solid-cast gun. The bore of this gun is fifteen inches in diameter, and thirteen feet long in the cyl- inder, which is terminated by an ellipsoidal chamber nine inches long, making the total length of bore one hundred and sixty-five inches, or thirteen feet nine inches long. The thickness of metal in the breech is twenty-five inches, and the total exterior length is fifteen feet ten inches. The greatest exterior diameter at the muzzle is 48.1 inches. The weight of the gun is 49,009 pounds. It is to carry a shell of three hundred and fifty pounds, and a solid shot of four hundred and tw r enty-five pounds weight. In illustration of the advantage of the mode of casting adopted in this gun, a specimen of cast iron, cut from a shaft cast in the usual way, was recently exhibited at a meeting of the Franklin Institute, Philadelphia. In the middle of the piece, where the iron had retained its heat and softness for the longest time, the contraction of the surrounding parts had caused the metal to assume an open, loose character, whilst the central portion was thrown into groups of spiny formation, resembling frost-work. Experiments made with Rod- man's gun at Old Point Comfort, Va., are reported as highly satisfactory. THE CONSTRUCTION OF ARTILLERY. The very interesting question of the best method of construction to be adopted for artillery has recently been handled with unusual detail by a body of gentlemen who, it may fairly be presumed, possess peculiar qualifi- cations for forming an authoritative opinion on the point. On the fourteenth of last February, Mr. Longridge, a civil engineer of considerable eminence, read before the London Institution of Civil Engineers a paper on the subject; and so great was the interest excited by his essay, that the discussion which fol- lowed it was canned on for five consecutive evenings, being sustained by a large number of the most distinguished authorities on the question, military as well as civil. Although there was, as might have been expected, consid- erable difference of opinion, often on points of no small importance, among the gentlemen who took part in this lengthened debate, still, the complete ventilation of this momentous question at the hands of such competent authorities cannot but excite great interest. From a printed report of this discussion we derive the following abstract: The one point to which Mr. Longridge has directed his efforts is the construction of a gun which shall be able perfectly to resist the utmost force of the explosive compound which maybe used in it; in other words, the manufacture of a gun which gun- powder cannot burst. In order to effect this, it becomes, in the first place, necessary to ascertain, approximately, at least, the actual amount of the MECHANICS AND USEFUL ARTS. 51 force generated by the explosion of gunpowder, a point on which artillerists are as yet very far from being completely agreed. Robins, who first at- tempted its determination, valued it at one thousand atmospheres, or nearly seven tons on the square inch; Hutton, who endeavored to ascertain it by meiins of the ballistic pendulum, estimated it at from thirteen to seventeen tons; and Captain Boxer, whose method consists in measuring the actual bulk of permanent gas evolved by the combustion of a known amount of gunpowder, arrives at the result of rather more than twenty-two tons. Inde- pendently of the great discrepancy between these several estimates, Mr. Longridge declines to receive them, on the ground of the inaccuracy of the methods by which they have been made. In the last method, especially, there appears to be several sources of error; for not only has the heat gener- ated by the combustion of gunpowder never been experimentally determined, but, it is also quite possible that the expansion of gases at so extreme a temperature may not altogether be regulated by the law of Mariotte. ^Further, it presupposes the instantaneous com-ersion of the whole of the powder into gas. Mr. Longridge accordingly instituted a series of experi- ments of his own, based upon the determination of the amount of gunpowder required to burst a cylinder of known strength, from which he concluded that the ultimate force of the powder used government powder did not exceed seventeen tons per square inch. This amount of force can never, he says, be permanently resisted by a gun made of cast iron, a material whose tensile strength is estimated at not more than eight tons per square inch, especially if, as is generally the case in England, the gun be cast solid, and subsequently bored, since the unequal rate of cooling of the inner and outer parts cannot fail to produce serious flaws in its mass. All the money, there- fore, which is now being spent in rifling cast-iron ordnance is simply thrown away. The same objection applies to the construction of a gun by a single casting from any homogeneous material whatever. The only way of attain- ing the maximum of strength is, to build up the gun, layer by layer, in such a manner that each successive layer, from within outward, shall be in a progressively increasing state of tension. It is on this principle that the guns of Sir W. Armstrong, Mr. \Vhitworth, and Captain Blakely are made. The method of carrying it out, however, adopted by all these gentlemen, consists in encircling a central tube, of various material, with successive rings of iron, which are either shrunk on by cooling, or forced on when cold by hydraulic pressure. This mode of operation can never, says Mr. Long- ridge, lead to perfectly satisfactory results. The extreme nicety with which the tension of each successive layer ought to be regulated the deviation of one five-hundredth of an inch from the required size being sufficient to materially impair the strength of the gun can never be arrived at by the contraction of a heated ring; and the rings, however put on, must sooner or later be loosened by the repeated shocks of the explosion. The plan proposed by Mr. Longridge is, to wind round a central tube successive spiral layers of steel wire, until the desired strength is attained, the greatest attention being paid to the exact tension of each successive layer. He does not enter at all into the question of what is the best material for the central tube. On the contrary, his sole object being to exhibit in the most striking light the immense power of resistance given by the layers of wire, he appears purposely to have made the core as weak as he well could. The results of a series of private experiments on a small scale were so encouraging that he constructed a brass cylinder, of about three inches bore and a yard long, 52 ANNUAL OF SCIENTIFIC DISCOVERY. wound round with coils of square steel wire, of the sixc of one-sixteenth of an im-h, the coils being six deep at the breech, and diininis.hin.u- to two at the muzzle; and, after subjecting it to a severe proof, submitted it, in June, 18')'), to the Select Ordnance Committee. The decision not being favorable, Mr. Lonu'ridge continued his experiments, employing a cylinder of cast iron instead of brass, and succeeded in producing a gun, weighing only three hundred pounds, which could throw a shot of seven and a half pounds to the distance of a mile, a result which, he believes, is not attainable by any six-pounder in the service. He further extended his invention to the construction of cylinders for hydraulic presses, and succeeded in combining the two very desirable qualifications of lightness and strength to a degree far beyond anything that has been attained by any other mode of construction. Such, briefly, are the principal points which were submitted by Mr. Long- ridge to the meeting. We have already said that in the discussion which followed many of the most distinguished authorities, civil and military, took part. It seems to be generally admitted that, as far as regards mere strength, Mr. Longridge's guns arc likely to be superior to any others. Most of the objections which are made to his plan are based upon the difficulty of securing the wire firmly at the breech and the muzzle; points which, says Mr. Longridge in reply, present no real difficulty at all. Several gentlemen speak up in favor of cast iron as a material for artillery. Mr. Haddan and Mr. Bashley Britten, to whom the task of rifling the exist- ing iron ordnance has been chiefly entrusted, both declare that, for ranges of from three to four thousand yards, the old guns are all that can be de- sired. They urge, with considerable cogency, that a longer range than this is not practically required. In order to make sure of hitting even a large object at six thousand yards or upwards, it is necessary to throw away in ascertaining the range more shot than can, with a due regard to economy, be spared. Cheapness must be an important element in the calculation. An old iron gun, who.se value is not more than .20, can be rifled for thirty shillings, and so enabled to throw shot to a distance of more than three thousand yards; and it is bad economy to spend 200 on an Armstrong twelve-pounder, whose performance is but little if at all superior. Mr. Conybeare and other gentlemen extol the American system of casting iron guns hollow, and cooling them from within outwards, by passing through them a continual stream of cold water, while the outside is kept heated. This method secures the advantage of keeping the outer portion of the gun in a greater state of tension than the inner; and Mr. Conybeare anticipates that the gun of the future will be of cast iron, and manufactured in this manner. But the truth appears to be, that cast iron, though not so utterly untrustworthy as is asserted by Mr. Longridge, cannot be relied upon as a material for artillery. One gun may survive thousands of discharges, and another, made of the same iron, and under the same circumstances, may burst at the first discharge. Sir C. Fox advocates the use of iron alloyed with wolfram or titanium; and Mr. Abel, the chemist to the Ordnance Department, states that a compound far superior in tenacity to ordinary gun-metal may be obtained by mixing copper with from two to four per cent, of phosphorus. But there is little doubt that, as far as is yet known, the only reliable guns are those which arc built upon one modification or another of the new principle. Mr. Lancaster says a few words respecting the bursting of his guns in the Crimea, a misfortune which has since then been frequently cited as a proof of the inefficiency of his system. The acci- MECHANICS AND USEFUL ARTS. 53 dent was entirely owing to the faulty construction of the shells which were at first used. They were made in two parts, and welded together, and the weld being- occasionally imperfect, the flame of the explosion penetrated into the shell, which burst in, and of course shattered the gun. Shells made in one piece were at once substituted, and nothing of the sort has since occurred. In regard to the effect of twist in rifled guns, every artillerist seems to have his own ideas as to the degree of it to be given, varying from Mr. Had- dan's one turn in forty feet to Mr. Whitworth's one turn in forty inches; but not one of them takes the trouble to give his reasons for selecting the precise pitch which he has decided to adopt. Mr. Haddan, indeed, believes that a very rapid tAvist is likely to burst the gun; and Mr. Whitworth says vaguely that it is very desirable to give a very rapid rotation to the projec- tile; but neither one nor the other cites either facts or theories in support of his view. Mr. W. B. Adams regards rifling merely as a device for correct- ing the defects of badly constructed projectiles; and as it involves a consid- erable waste of propelling power, he hopes before long to see it dispensed with altogether, by the employment of more accurately-made shot. Perhaps the most obvious and striking conclusion that is deducible from the whole of this discussion is, that the science of artillery is as yet in its infancy. There is not a single point of importance on which the most opposite opinions are not held by the most competent authorities. To spec- ulate on the causes which have led to this extraordinary neglect on matters of such vital import would be a task more easy than profitable. SCIENCE IN THE BATTLE-FIELD. The following is an abstract of a lecture recently delivered before the Royal Institution, London, by Mr. F. Abel, Director of the chemical establish- ment of the War Department of Great Britain, " On the recent Applications of Science in Reference to the Efficiency and Welfare of Military Forces." One of the most important subjects in connection with military equipment, and one which has recently received a very large share of general attention, relates to the changes which have gradually been effected in the nature of material, and the principles of construction, applied to the production of cannon Until very recently, the materials used for cannon have been only of two kinds east iron and bronze, or, rather, the alloy of copper and tin, known as gun-metal. Of these, the latter is by far the most ancient. Guns were cast of bronze in France and Germany about 1370, and from that period until the close of the fifteenth century this material gradually replaced wrought iron, of which guns were constructed in the first instance. An examination of such iron guns of early date as are still in existence such as the Mons Meg, of Scotland, the great gun of Ghent, and others shows that the principles involved in their general construction are precisely those which have just been most successfully applied to the production of wrought iron rifled guns in this country. Those ancient guns were built up of stave- bars, arranged longitudinally, upon which wrought-iron rings were shrunk. The very imperfect nature of those structures, arising from the primitive condition of mechanical and metallurgic appliances at that early period, rendered their durability exceedingly uncertain; and it is therefore not surprising to find that compound guns of this class were gradually replaced by cannon cast in one piece. Even the great expense of bronze, as com- 5* 54 ANNUAL OF SCIENTIFIC DISCOVERY. pared with iron, was counterbalanced by the vast amount of time and labor which must have been bestowed on the construction of the old wrought-iroa guns. Although cast iron was applied to the production of shot and other pro- jectiles at the close of the fourteenth century, it was not until about 1000 that cannon were made of this material. In proportion as the facility of its production increased, its application in this direction was gradually ex- tended; but in no country has it ever entirely superseded bronze or gun- metal, which, on account of its superior tenacity, has always been employed for the construction of light field-guns. This alloy possesses, however, some very serious defects, arising principally out of its softness, and its consequent incapacity to resist the injimous effects of rapid firing. Numerous experi- ments have been made with alloys of copper, and, recently, with other com- binations of that metal, with the object of discovering some material at least equal to gun-metal in tenacity, and superior to it in hardness and also in uniformity. Alloys of copper and aluminum have been proposed; but, apart from the present great cost of aluminum, the readiness with which this metal is attacked by alkaline substances, and the powerful corrosive action which portions of the products of decomposition of powder conse- quently exert upon it, preclude its application to the production of a substi- tute for gun-metal. The effect of silicon in hardening and greatly increasing the tenacity of copper has also received attention; and there appears little doubt that, the difficulty of producing on a large scale a uniform compound of copper and silicon once overcome, such a material would prove a most valuable substitute for bronze. The effects of a small quantity of phosphorus upon copper are similar to those of silicon; the metal is greatly hardened, its uniformity may be ensured, and its tenacity is also much increased. Copper containing from two to four per cent, of phosphorus will resist a strain of from forty-eight to fifty thousand pounds on the square inch, while the average strain borne by gun-metal is about thirty-five thousand pounds. Uniform compounds of phosphorus and copper can, moreover, be prepared without difficulty upon a large scale. By immersing pieces of phosphorus for a short time in a solution of sulphate of copper, they become coated with a film of the metal, so that they may be safely handled, and thrust beneath the surface of liquid copper before the coating melts; thus the phosphorus is readily combined with the copper without, loss. The great success which has recently attended the construction of mallea- ble iron guns appears, however, to render it doubtful whether any of the compounds above referred to, or others of a similar character, will ever receive employment as materials for cannon. Attempts have been made from time to time, for many years past, to produce forgings of malleable iron of sufficient size for conversion into cannon. The great difficulty of insuring anything approaching uniformity of chemical composition and physical properties in cast iron, and the consequent great variation and uncertainty of the enduring power of guns made of that material, acted as powerful incentives for the prosecution of such experiments. Experience gained during the late war was also unfavorable, partly to the employment of cast iron as the material for the heaviest pieces of ordnance, and partly to the system of casting those hitherto in use. The attempts made by Xasmyth and others to produce large forgings, sufficiently perfect for conversion into cannon, were, however, uniformly attended with failure, excepting in the instance of a very large gun thir- MECHANICS AND USEFUL ARTS. 55 teen-inch calibre constructed at the Mersey Company's works, which has successfully withstood some severe trials, though even this gun is not a per- fectly sound forging throughout. This want of success is ascribed partly to the difficult} 7 of ensuring perfect welds throughout a very large forging, and partly to a change which is graduallj 7 effected in the physical structure of the metal by its repeated exposure to a high temperature, and possibly, also, in some measure, by its frequent subjection to powerful concussion. In large masses of wrought iron, which have been built up by welding, the fibrous structure of the metal is always found to have passed over, more or fess perfectly, into a lamellar structure, and the strength of the mass thus becomes very considerably diminished. While unsuccessful attempts to construct cannon of large masses of mal- leable iron were still in progress, Mr. Mallet, Captain Biakeley, and others, who had given the subject of the construction of cannon of large size their serious attention, and had applied mathematical reasoning to its elucidation, had arrived at the conclusion that the true system to be followed was that of constructing cannon of several parts, combined in such a manner as to render every portion of the metal available in resisting, by its tenacity and elasticity, the strain exerted upon the gun by the explosion of powder. The method of construction proposed by those gentlemen consisted in preparing, in the first instance, cylinders (or rings, to be afterwards braced together), and in shrinking upon these other rings, of which the internal diameter was somewhat less than the external diameter of the first rings or the cylinder. The latter are thus placed in a state of compression, while the external rings are in a state of tension. Other rings are again shrunk upon the outer ones, according to the size of the gun and the strain which it has to bear. In this way the whole of the metal composing a heavy gun or mortar is arranged in a condition most favorable to the effectual resistance of a sudden strain applied from the interior. A gun constructed on this plan, by Captain Biakeley, has exhibited very great enduring powers. Two enormous mor- tars have also been constructed by Mr. Mallet on the same principle; and, although the trials with one of these were only partially successful, the cor- rectness of the principles above referred to were in no way impugned by the results obtained. The methods adopted for the production of the beautiful rifle-gun invented by Sir William Armstrong, which is rapidly replacing the old bronze field- guns, afford an interesting illustration of the application of the above sys- tem to the construction of very light and dm-able cannon. This gun consists essentially of rings partly welded together, so as to produce a cylinder or barrel of sufficient length, and partly shrunk one upon another, so as to im- part the requisite strength to the structure. The rings themselves are from two to three feet in length, and are formed out of long bars, which are coiled up, when at a red-heat, into spiral tubes, and afterwards Avoided into solid rings or tubes by a few blows from the steam-hammer, applied to one end of the heated coil, while in a vertical position. The rings are united, to form the ban-el of the gun, by raising to a welding-heat the closely proximate extremities of two rings, placed end to end, and then applying a powerful pressure to the cold ends of the rings. In the large guns, a second layer of rings is shrunk on to the first set, or barrel, throughout the length; but in the smaller guns it is only behind the trunnions that two additional rings are shrunk on, one over the other. The outer ring is exactly like those already described ; but the intermediate one is prepared by bending two iron slabs into a 56 ANNUAL OF SCIENTIFIC DISCOVERY. semi-cylindrical form, and then welding them together at the edges. In this way a cylinder is obtained in which the fibre of the iron is arranged longi- tudinally, instead of transversely as in the other rings. This arrangement is adopted because that part of the gun has to sustain the principal force of the thrust upon the breech, on the discharge. It is into this portion that the breech-screw made of steel fits, by means of which a movable plug of steel, provided with a soft copper washer, is pressed up against the end of the barrel when the gun has been loaded. The breech-screw being hollow, the charge is introduced through it into the gun, on the removal of the plug. This gun, built up of so many pieces, accurately welded, and turned, and fit- ted, with its thirty or forty grooves, its neat lever arrangement for working the breech-screw, its admirable sights for giving direction, and various other arrangements, contrived so as to render it a most complete and perfect weapon, is undoubtedly very costly as compared with the ordinary cast-iron gun. But, owing to the admirable system of manufacture, and the beautiful mechanical appliances brought to bear upon the production of each part, the original cost of the gun has already been very much diminished. On com- paring the price of a twelve-pounder gun with that of a bronze gun of the same calibre, which it has now superseded, the latter is found to be about double the expense. The price of iron used for the manufacture of the Armstrong gun is nineteen pounds per ton. It is the best description of malleable iron, bearing a tensile strain of about seventy -four thousand pounds on the square inch. The present cost of a twelve-pounder gun, weighing eight hundred weight, is about ninety-three pounds. The value of gun-metal is about one hundred and twenty-five pounds per ton; and the cost of a twelve-pounder gun of this material, weighing nineteen hundred weight, is one hundred and seventy -five pounds ten shillings. Of the latter, it may be said, that when no longer serviceable it may be recast, while an old Armstrong gun cannot be reconverted into a new one. But, on the other hand, the average number of rounds which can be fired from the old gun before it is unserviceable scarcely exceeds one thousand; while the limit to the power of endurance of the Armstrong gun is not yet known. Between five and six thousand rounds have been fired from one, without any vital injury to the gun. While these important results have been obtained with guns of wrought iron, built of rings, others, scarcely less valuable, have attended the applica- tion of materials, varying in their nature between steel and malleable iron, to the production of light guns, cast in one piece. M. Krupp, of Essen, was the first to produce masses of cast steel of sufficient size for conversion into cannon. A twelve-pounder gun, cast of this material, was experimented upon in this country several years ago, and exhibited the most extraordinary powers of endurance, having withstood the heaviest proofs without bursting. Similarly good results were obtained with cast steel in France and Germany, and it is now applied to the construction of the rifled field-guns in Prussia. A cast material, somewhat similar in character to this steel of M. Krupp, and to which the name of homogeneous iron has been given, has recently received most successful application in the hands of Mr. "Whitworth, not only to the production of the barrels for his rifle small arms, but also to the manufacture of his beautiful rifle-cannon. The smaller cannon are cast in one piece, and then forged to the required form. The heavy guns eighty and hundred pounders consist, however, of cylinders of homoge- neous iron, upon which hoops of fibrous iron are forced by hydraulic pres- MECHANICS AND USEFUL ARTS. 57 sure, the breech portion receiving hoops of puddled steel. The small TVhit- wm-th guns undoubtedly possess the great advantage of simplicity of con- struction over the compound guns just described; but the present great ex- pense of the material gives the latter the advantage in point of cost. There can lie little doubt, however, that the facilities for obtaining products of this description will increase with the demand; and there appears no reason why the process of Mr. Bessemer, which has recently been applied with great success to the conversion of iron of good chemical quality into excellent cast stce!, upon a very considerable scale, should not be resorted to for the production, at a moderate cost, of masses of cast steel, or a material of a similar character, of sufficient size for conversion into cannon of all sizes but those of the heaviest calibre, which it will, perhaps, always be found most advantageous to construct of several pieces, upon the principles just now referred to. The improvements effected in the construction of fire-arms have rendered indispensable a careful revision of the descriptions of gunpowder hitherto used, which has already led to the modification of several important points in the manufacture of powder, whereby a greater uniformity in the action of the latter is ensured, and its explosion is regulated with especial regard to the double woi'k which it now has to perform in the greater number of rifled arms, namely, that of propelling the projectile, and of expanding it into the grooves of the rifle. Considerable attention has been devoted in different continental states, during the last few years, to the application of the different forms of elec- tricity to the discharge of mines. The many serious inconveniences attend- ing the employment of voltaic batteries for that purpose in the field, have led to the use, with considerable success, of the arrangements contrived by Ruhmkorff and others for the production of powerful electro-magnetic cur- rents. The application of the induction-coil machine, with appropriate fuse arrangements, for the ignition of the mine by means of the spark, led to a very great reduction in the size of the battery required even for extensive operations. The necessity, howcvefr, of still using a battery, and the great liability to injury of the induction apparatus, have rendered the advantage to be attained by their employment somewhat questionable. In Austria very important results are said to have been obtained by the employment of fric- tional in the place of voltaic electricity. A very portable arrangement of a plate-electric machine, with Leyden jars, and a small stove to protect the apparatus from damp, has been employed with success in some extensive operations, as many as one hundred charges having been fired simultaneously by its means. Professor Wheatstone and Mr. Abel have carried on numer- ous experiments on the application of electricity in this direction; and, at the suggestion of the former, attempts were made to employ the electricity ob- tained by induction from permanent magnets. No difficulty was experienced in igniting a single charge by its agency; but it was found that the ignition of more than one charge could not be effected with certainty "by the employ- ment even of the most powerful magnets and the use of fuses containing very sensitive compositions. Eventually, a fuse arrangement was contrived and a composition prepared by Mr. Abel, with the employment of which the ignition of several mines could be effected with certainty, by means of one of the small magnetic arrangements employed by Mr. Wheatstone in his portable telegraphs; and an ingenious combination of several such magnets, arranged in a form very portable and readily worked by any soldier, can be 58 ANNUAL OF SCIENTIFIC DISCOVERY. applied with equal certainty to the discharge of a considerable number of mines. The great clement of success in the fuse-composition employed is to be found in the circumstance that it combines a high degree of sensitiveness with considerable conducting power. The substitution of the magnet for" the voltaic and other arrangements hitherto used will greatly facilitate min- ing operations; the soldier requires but little instruction in its use; with ordi- nary care it is not liable to derangement; it is very transportable, and ready for application at the shortest notice. In connection with submarine operations, vulcanized India-rubber bags have become valuable substitutes for the wooden and metal receptacles hith- erto employed for the charges of powder. The numerous applications which India-rubber, especially in its vulcanized form, now receives in connection with military equipments, render it a most indispensable material. Thus it has been applied to the preparation of waterproof linings for powder-barrels, waterproof cases for cartridges, convenient holders and waterproof coatings for percussion caps. It is used in the form of springs and buffers in connec- tion with gun-carriages and the beds of heavy mortars ; ambulance wagons are supplied with efficient and easily applicable springs of India-rubber; and one of the most important additions recently made to the comfort of troops has been the general supply to them, when on active service, of waterproof clothing and covers, to be used in camp. The protection of camp-erections from fire has also received attention, with successful results. A cheap and ready mode of applying a coating of insol- uble silicate of lime and soda to the surface of camp huts, whereby very important protection against fire is attained, received application a few years ago; and quite recently a method has been devised, by Mr. Abel, of impreg- nating tent-cloth with silicates to such an extent as effectually to prevent fire from spreading, when applied to any portion of it, and in such a form as to enable them to resist the solvent effects of drenching rains. The application of soluble silicates to the preparation of very porous arti- ficial stone has enabled Mr. Ransome to produce portable filters, by the aid of which the soldier may frequently be enabled to partake of water which otherwise would be unfit for use. A still more efficient portable filter is now, however, prepared of carbon, in a porous condition, which not only has the property of retaining the mechanical impurities of water in its passage through it, but also will purity it to a very considerable extent from injurious organic matters and gases Avhich it may contain. One of the most important improvements which has yet been effected in the purification of water, and one which has already received important ap- plication in connection with the military sen'ice, is presented in the appara- tus contrived by Dr. Normandy for the preparation of wholesome and pleas- ant water from sea or other water unfit for consumption. The apparatus consists, in the first instance, of a great improvement on the condensing arrangement contrived by Sir T. Grant, which has been for some time used in the navy. The heat abstracted from the steam first consumed is applied to the distillation of a second similar quantity of water, and the arrange- ment employed for condensing this second product is of such a nature as to ensure a very gradual but continuous replacement of the condensing water. In this manner the latter becomes sufficiently heated, before it passes out of the apparatus, to part with the gases which it contains in solution, and which are made to pass into the distilling apparatus and mix with the steam. The condensed product is thus thoroughly aerated; it is then, finally, made to MECHANICS AND USEFUL ARTS. pass through a charcoal filter, which completely deprives it of the disagree- able empyreumatic flavor always possessed by distilled water. Imk'pen- dently of the applications which this apparatus is receiving to the supply of ships with water, it has proved very valuable in readily and continuously producing large quantities of wholesome water for the supply of troops at stations where the only water procurable was unfit for consumption. The important subject of the economical supply of well-cooked, and pala- table food to troops in barracks and on active service, which had been consid- erably neglected previous to the late war, has received great attention on the part of Captain Grant; and the results of his labors in this direction have been the production of most efficient cooking-ranges for barracks, and equip- ments for cooking in the field. By the employment of the range, with oven attached, which has been contrived by him, and is used at Aklershott, \Vool- wich, and other military stations, the cost of cooking for a large number of troops eight hundred to one thousand being supplied with food from one range has been reduced to a halfpenny per man per week; and, by further improvements which Captain Grant is just carrying out, it will still be subject to considerable reduction. The food is, at the same time, cooked in various ways, by means of the oven and other appliances. An arrange- ment has been devised by Captain Grant, and used by troops with great suc- cess, for cooking in the field in long cylindrical boilers, which are so disposed over ti-enches dug for the purpose that, Avith a very small consumption of fuel, well-cooked food may be supplied from eight of them, in between two and three hours, sufficient for eight hundred men. These kettles are of such a form that they may also be made to serve the purpose of pontoons in the construction of bridges. The subjects briefly discussed in this discourse can only be regarded as examples of the many directions in which every branch of science has recently received application in connection with the military service. PROPERTIES OF GUNPOWDER. Mr. Fairbairn, F. R. S., has communicated to the Philosophical Society of Manchester the following results of "An Experimental Inquiry into the Effect of severe Pressure upon the Properties of Gunpowder." During the late war, the author received from the government authorities different sam- ples of gunpowder, for the purpose of submitting them to severe compres- sion, in order to ascertain the effect of close contact between the particles upon its explosive properties. At the government works there is no ma- chinery of sufficient strength to give a pressure of more than five thousand to six thousand pounds per square inch; and as it was considered advisable to test the quality of the powder under the influence of greatly increased pressure, the author was requested to compress it in an apparatus of his own, calculated to effect its condensation under a force of more than sixty thousand pounds per square inch. By carrying the pressure in this way far beyond the ordinary limits, it was expected that the precise influence of compression on the properties of the powder would be more clearly and accurately exhibited. The samples of powder were placed in a wrought-iron box, and com- pressed by a lever, acting upon them by a solid piston, with a force varying from thirty-eight thousand to sixty-seven thousand pounds per square inch in the different specimens. When taken from the apparatus, the powder CO ANNUAL OF SCIENTIFIC DISCOVERY. was found to have been consolidated into cylinders of one and a quarter inches in diameter, with smooth, polished surfaces, every trace of its granu- lar character having disappeared. From the Report of Mr. Abel, the chemist of the War Department, we learn that the specific gravity of the specimens was increased by the pres- sure, but not to so great an extent as might have been expected. The specimens, having been granulated, were then burned, and it was found, on comparing the results with those of similar experiments on ordi- nary press-cake, that the amount of residue left by the compressed powders, after ignition, was greater in proportion as the pressure was increased. This increase of residue is probably to be attributed to the more gradual combustion and the diminished intensity of heat generated by compressed powder. Experiments were then instituted to determine the amount of charcoal left unconsumed in the residue. They showed conclusively that the con- densation of the powder had caused a more perfect chemical action in com- bustion, as the per-centage of carbon was considerably diminished in the compressed powders. Nitric acid was very carefully searched for in the residues of the compressed powders, but none could be detected, although in ordinary gunpowder a portion of the acid of the saltpetre always escapes decomposition. An important objection to the application of increased pressure in the manufacture of gunpowder, notwithstanding the more intimate mechanical mixture of its constituents, is, that the quantity of the residue left after com- bustion is increased, and a larger proportion of powder escapes ignition altogether when a charge is fired from a gun. If, however, larger quantities were submitted to compression, it is probable that the closer contact of the particles might be found to act beneficially, and a powder be produced of an improved and stronger quality, resulting from a judicious application of increased pressure and a more perfect system of granulation. Mechanics' ( London ) Magazine. Mr. Lynall Thomas, in a communication to the Royal Society, says: Since the year 1797, when Count Rumford made his experiments for ascer- taining the initial force of fired gunpowder, an account of which appears in the Philosophical Transactions of that year, very little light has been thrown on the subject. Count Rumford's experiments, valuable in many respects, afforded, indeed, nothing conclusive respecting it. The object of the present paper is to show the unsatisfactory natui'e of the present theory of the action of gunpowder, and to point out some of the principal errors upon which this theory is based. For this purpose, the results of various experiments made by the author, and which were repeated in the presence of a select com- mittee at Woolwich, are described and explained. These experiments are held by the author not only to afford complete evidence of the unsoundness of the present theory, but as sufficiently conclusive to serve as the basis for the formation of a new set of formula?, both correct and simple, in place of those at present in use. The initial action of the fired charge of powder upon the shot, the first movement of the shot itself in the gun, and the force exerted upon the gun by different charges of powdei', and, therefore, the actual strength of metal required by the gun, arc circumstances which, as the author believes, have not only been misunderstood, but for which laws have been assigned directly opposed to the truth. As an instance of tLis, the hitherto received theory supposes that when a shot is forced from a MECHANICS AND USEFUL AKT3. 61 gun. it acquires its velocity gradual!}", from the pressure cf the clastic fluid generated by the fired powder acting upon it through a certain space. It is also supposed that the initial pressure of the elastic fluid is the same in all cases, the quantities of powder being proportional, whether the gun from which the shot is fired be large or small; so that the larger the calibre of the gun, the slower the first movement of the shot is supposed to be. The result of the following experiment is given to prove that the first of these propositions is incorrect. The author placed a cast-iron shot, three inches in diameter, and three pounds fourteen ounces in weight, upon a chamber half an inch in diameter and half an inch deep. This chamber was formed in a block of gun-metal, and contained, when filled, one dram of powder. Upon lighting the powder, the ball was driven to a height of five feet six inches. When the ball was placed one-eighth of an inch over the chamber, the charge failed to move it. From this it is inferred that the first force of the powder is an impulsive force, that is to say, it imparts to the shot at once a finite velocity. In order to place the matter beyond a doubt, and to ascertain the relative force of different quantities of powder, the author caused a chamber to be made similar in form to, but of twice the linear dimensions of the former; he then placed a cast-iron ball, of six inches in diameter, upon the orifice of this chamber, which was filled with powder; upon firing the latter, the ball was driven up to a height of eleven feet; that is to say, to double the height of the smaller. The state of the metal in which the chamber was formed also showed the increase of the initial force of the powder. This is considered to be sufficient proof that the last two of the above-mentioned propositions are as incorrect as the first. Assuming the initial force of the powder to be of an impulsive nature,. it is not difficult to understand the increase of force shown in the last-named experiment, inasmuch as a certain time being required for the complete conversion of the powder into an elastic fluid, a quantity contained in a chamber of a similar form, but of greater linear dimensions than another, must ignite in a less comparative time, the linear dimensions increasing in the ratio of the first power, and the quantity of powder increasing in the ratio of the third power, so that the flame will traverse a larger quantity in comparatively less time. Thus it appears that the powder which inflames more rapidly has a much greater initial force, being more concentrated in its action; a quick burning powder, therefore, is better for ordnance of small length, such as mortars and iron howitzers. The different results pro- duced by powder of different quality have, according to the author, been entirely overlooked in the hitherto received theory. This theory, which considers the secondary force, namely, the elasticity of the fluid only, and takes no account whatever of the enormous impulsive or initial force pro- duced by the sudden conversion of the powder into an clastic fluid, is that which regulates the system upon which ordnance are at present constructed; hence the reason why large guns are so liable to burst so much so, that it has been said that no gun larger than a thirty-two pounder is safe to fire. From the variety of experiments made by the author, he arrives at the conclusion that when powder is of the same quality, and confined in cham- bers of similar form but, of different sizes, the initial force varies, within cer- U' 4 - tain limits, in the ratio of - J , where iv \& the weight of the powder, and w' of the ball. Thus, were this new theory recognized, the question of the increase of .strength, with increased thickness of metal, would wear an 62 ANNUAL OF SCIENTIFIC DISCOVERY. entirely now aspect. So far from the metal in large guns diminishing in strength in the proportion assumed, it will be a matter for inquiry how it resists the great strain to which it is subjected, rather than why it yields; for we find, from the experiments described above, that a sixty-eight pounder gun, which has a calibre of twice the diameter of a nine-pounder gun, must, when fired with the same proportionate charge of powder as the latter, continually be subject to as great a strain as the latter would suffer if always fired with the proof-charge, which is three times the quantity of the ordinary service-charge. Proc. Royal Soc. THE DENSITY AND TEMPERATURE OF STEAM. We extract from the London Engineer the following account read before the British Association for the Advancement of Science, by William Fairbaim, F. R. S. of some researches to determine the density of steam at all tem- peratures : I propose to give a short sketch of an apparatus and the results of the earlier experiments which, in conjunction with my friend Mr. Thomas Tate, I have been investigating by direct experiments, with the intention of deter- mining the law of the density of steam and other condensable vapors ; and thus to solve a hitherto almost untouched problem by an experimental method, which will verify or correct the theoretical speculations in regard to the relation between the specific A'olumc and temperature of steam and other vapors. The experiments are being conducted, it is believed, upon an en- tirely novel and original principle, and one which is applicable at any tem- perature and pressure capable of being sustained by glass vessels. For a perfect gas, the law which regulates the relation between temperature and volume is known as Gay-Lussac's or Dalton's law, and is expressed by the equation V X P 458 + tl (1.) V\ X PI " " 458 + t Now, density of steam has been determined with accuracy by direct experi- ment at the temperature of two hundred and twelve degrees and at that temperature only by the method of Dumas. At two hundred and twelve degrees Fahrenheit its density is such that its volume is one thousand six hundred and seventy times that of the water that produced it. Substituting these values of volume, temperature, and pressure, we get for the volume of steam from a unit of water at any other temperature, (2.) V This is the well-known and received formula from which all the tables of the density of steam have hitherto been deduced, and on which calculations on the duty of steam-engines have been founded. Up to the present time, however, this formula has never been verified by direct experiment, nor arc the methods hitherto employed in determining the density of gases and vapors applicable in this case, except at the boiling temperature of the liquid at the ordinary atmospheric pressure. But, on the other hand, theoretical MECHANICS AND USEFUL ARTS. 63 speculations throw considerable doubt on the accuracy of the above formula when applied to steam and other condensable vapors. Several years ago, Dr. Joule and Professor William Thomson announced, as the result of applying the new dynamical theory of heat to the law of Carnot, that, for tempera- tures above two hundred and twelve degrees Fahrenheit, there is a very con- siderable deviation from the gaseous laws in the case of steam. Later, in 18-55, Professor Maquorn Rankine has given a new theoretical formula for the density of steam, independent of Gay-Lussac's law, and confirmatory of Professor Thomson's surmise. But as yet these speculations need the evi- dence and verification of direct experiment. The density of steam is ascertained by vaporizing a known weight of water in a glass globe of known capacity, and noting the exact temperature at which the whole of the water becomes converted into steam. From these three elements volume, weight, and temperature the specific gravity is known. But in pursuing this method, these two difficulties must be over- come : First, the pressure of the steam renders it necessary that the glass globe should be heated in a strong, and consequently opaque, vessel; second, as steam rapidly expands in volume for any increase of temperature, beyond the temperature of saturation, it would, in any case, be impossible to decide by the eye the temperature at which the whole of the water became vapor- ized. The temperature of saturation, or temperature at which the whole of the moisture is converted into steam, while no part of the steam is super- heated, must be determined with the utmost accuracy, or the results are of no value. The difficulties thus resolve themselves into finding some other test of suf- ficient accuracy and delicacy to determine the point of saturation. This has been overcome by what may be termed the saturation gauge; and it is in this that the novelty of the present experiments consists. To illustrate the principles of the saturation gauge, suppose two globes, A and B (Fig. 1), connected by a bent tube containing mercury at a b, and placed in a bath in which they can be raised to any desired temperature. Suppose a Torricellian vacuum to have been created in each globe, and twenty grains of water to have been added to A, and thirty or forty grains to B. Now, suppose the temperature to be slowly and uniformly raised around these globes; the water in each will go on evaporating at each temperature, being filled with steam of a density corresponding to that temperature, and the density being greater as the temperature increases. At last a point will be reached at which the whole of the water in globe A will be converted into steam ; and at this point the mercury column will rise at a, and sink at 6. This is the saturation test, and the cause of its action will be easily seen. So long as vaporization went on in both A and B, and the temperature was main- tained uniform, each globe would contain steam of the same pressure, and the columns of mercury, a and b, would remain at the same level. But so soon as the water in A had vaporized, and the steam began to superheat, the 6-1 ANNUAL OF SCIENTIFIC DISCOVERY. pressure in A would cease to remain uniform with the pressure in B, and Ilic mercury column woul.l at oii'v l-ill, and thus indi'-atc the difference. The ::,- tantuur'>i:s change of the position 01' the iiK-ivury is the indication of the point at whi'-h the temperature iu the bath corroponds with the saturation point of the steam in A. To show the delicacy of this test, I may instance that, at two hundred and ninety decrees Fahrenheit, the meivury column would rise nearly two inches for every decree of temperature above the saturation point, as the increase of pressure arising from vaporization is twelve times that arising from ex- pansion in superheating at that point, and a similar difference exists at other temperatures. The apparatus, as employed for experiment, vanes according to the pres- sure and other circumstances of its use. Fig. 2 represents one of the arrangements which has been employed with success. It consists of a glass globe of about seventy cubic inches capacity, in whk'h is placed, after a Torricellian vacuum has been formed, the weighed globule of water. The globe, with the stem, is shown at A ; this is surrounded by a copper boiler, B B, prolonged by a stout glass tube, C, enclosing the globe stem. This copper boiler forms the water and steam bath through which the globe is- heated, and, in fact, corresponds to the second globe, B, in the former figure. The fluctuating mer- cury column, or saturation gauge, is placed at the bottom of the tube, C, and the satu- ration point is indicated by the rise of the inner mercury column, a, and the fall, at the same time, of the outer mercury col- umn, b. As soon as the whole of the water in the globe A is evaporated, there is an instantaneous rise of the inner mer- cury column to restore the balance of pres- sure, and that progressively with the rise of temperature. As an auxiliary apparatus, the boiler is provided with gas-jets, E, to heat it, and with an open oil bath, G, to retain the glass tubes at the same temperature as the boiler; and this oil bath is placed on a sand bath and also heated with gas. A thermometer, D, registers the temperature, and a pressure-gage, F, the pressure of the steam; and a blow-off cock, H, serves to iv.'.ucc the temperature when necessary. A number of results have already been obtained, but they arc not yet sufficiently advanced to be made public. The follow- ing numbers have been, however, approxi- mately reduced from the theoretical formula above, and the experimental MECHANICS AND USEFUL ARTS. 65 results may illustrate the use of this method of research. The most con- venient way of expressing the density of steam is by stating the number of volumes into which the water of which it is composed has expanded. Thus, one cubic inch of water expands into one thousand six hundred and seventy cubic inches of steam at two hundred and twelve degrees Fahrenheit; into eighteen hundred and eighty-two cubic inches at two hundred and fifty-one de- grees, and into four thousand cubic inchcs^R: three hundred and four degrees, and so on. In this way, the following numbers have been computed : Volume of steam. Temperature. By formula. By experiment. 244 .... 1,005 896 245 . . . . .939 890 257 . . . .790 651 22 ... .740 680 268 .... 680 G33 270 660 604 283 . . . .240 490 These determinations, at pressures varying from ten pounds to fifty pounds above the atmosphere, are not accurate reductions from the experimental re- sults, but only approximations. But they uniformly show a decided deviation from the law for perfect gases, and in the direction anticipated by Professor Thomson, the density being uniformly greater than that indicated by the formula. I hope, by the time of the next meeting of the association, with the assistance of my friend Mr. Tate, to be enabled to lay before the section a series of results which will fully determine the value of superheated steam, and its density and volume compared with pressure at all pressures, varying from that of the atmosphere to five hundred pounds on the square inch. THE ATMOSPHERIC TELEGRAPH. The Atmospheric Telegraph, or device for transmiting small packages through air-tight tubes by atmospheric pressure, which was attempted to be introduced in this country some years since by Mr. Richardson, of Boston, has been recently put into practical operation by the International Telegraph Company of London. Their chief office in that city has been for some time in working communication not only with the Stock Exchange, but also with all the subordinate telegraph stations in the outskirts of London, and written messages .arc constantly transmitted through the tubes thus avoiding the necessity of repeating each message. " We witnessed," says the London Times, " the apparatus doing its ordinary work the other day in the large telegraphic apartment of the company in Moorgate Street. Five metal tubes, of from two to three inches in diameter, are seen trained against the wall, and coming to an abrupt termination opposite the seat of the attendant who ministers to them. In connection with their butt-ends other smaller pipes are soldered on at right angles; these lead down to an air-pump below, worked by a small steam-engine. There is another air- pump and engine, of course, at the other end of the pipe, and thus suction is established to and fro through the whole length. Whilst we are looking at the largest pipe we hear a whistle; this is to give notice that a despatch is about to be put into the tube at Mincing Lane, two-thirds of a mile dis- tant. It will be necessary, therefore, to exhaust the air between the end we G* C6 ANNUAL OF SCIENTIFIC DISCOVERY. are watching and that point. A little trap-door the month of the appara- tus is instantly shut, a cock is turned, the air-pump below begins to suck, and in a few seconds you hear a soft thud u_-;>.h:st vhe end of the tube; the little door is opened, and a cylinder of gutta-percha, encased in flannel, about four inches long, which tits the tube, but loosely, is immediately ejected upon the counter; the cylinder is opened at one end, and there we find the de-- patch. "Xow it is quite clear that it is only necessary to enlarge the tubes and to employ more powerful engines and air-pumps in order to convey a thou- sand letters and despatches, book parcels, etc., in the same manner. And this the company are forthwith about to do. At the present moment the contract rate at which the mail-carts go is eight miles per hour. The Pneu- matic Company can convey messages at the rate of thirty miles an hour, and this speed can be doubled if necessary. "The company arc also about to lay down a pipe between the Dock and the Exchange, for the conveyance of samples of merchandise, thus practi- cally bringing the Isle of Dogs into Cornhill ; and for all we know this in- vention may hereafter be destined to relieve the gorged streets of the metrop- olis of some of its heavy traffic. " At the station of the International Telegraph Company, in Telegraph Street, the pipes wind about from room to room, sufficient curve being main- tained in them for the passage of the little travelling cylinder which contains the message, and small packages and written communications traverse al- most as quickly in all directions as does the human voice in gutta-percha tubing, to which in fact it is the appropriate addendum." THE CLEARING OF DRAINS AND WATER-COURSES. Messrs. Easton & Amos, of London, have patented a curious method of adopting to some convenient part of a drain, sewer, or water-course, a grat- ing, of peculiar construction, whereby any extraneous solid matters, such as weeds, pieces of wood, brickbats, stones, the dead bodies of animals, or other substances, may be arrested in their progress, and removed, so as to prevent them from blocking up the water-course and stopping the flow of the water. To this end a chamber or recess is constructed at some convenient part of the drain, sewer, or water-course, and made to extend across it from side to side. In this chamber is mounted a movable grating in such a manner as to extend transversely across the whole of the water-way. The grating is to be formed of a suitable number of endless chains, connected together later- ally in any convenient manner, and provided with projecting pins, points, or hooks. Or a number of short bars, similarly provided with projecting pins, may be jointed together in an endless series, so as- to form an endless grat- ing, which is to be passed round wheels or rollers mounted in the chamber or recess. This endless chain or grating should not be placed vertically, but at an inclination to the line of the drain or sewer. It will be understood that the water and liquid matters will pass freely through the endless chain or grating, but that solid matters of any great size or dimensions, or that would be likely to cause an obstruction in the water-course, will be arrested by the grating, and by causing the same to rotate (by communicating motion to the wheels or rollers on which the endless chahi or grating is mounted), the pins, points, or hooks attached to the grating will be caused to lift up siu-h solid matters out of the chamber formed in the drain, and deposit them in. some receptacle provided above for that purpose. MECHANICS AND USEFUL ARTS. 67 KEVT MICROMETER FOR MEASURING LARGE DISTANCES. \ At a recent meeting of the Royal Astronomical Society, England, Mr. Alvan Clark, of Boston, Mass., exhibited a micrometer, invented by himself, which is capable of measuring with accuracy any distance up to about one degree. It is also furnished with a position-circle. Its character is essentially the same as that of the parallel-wire micrometer; but it has sonic peculiarities, not, it is believed, previously introduced, and on which its wide range de- pends. The most remarkable of these peculiarities consists in its being fur- nished with two eye-pieces, composed of small single lenses, mounted in sepa- rate frames, which slide in a groove, and can be separated to the required distance. A frame carrying two parallel spider-lines, each mounted sepa- rately with its own micrometer screw, slides in a dovetailed groove in front of the eye-pieces; and, by a free motion in this frame, each web can be brought opposite to its own eye-lens. In using this micrometer, the first step is to set the position-vernier to the approximate position of the objects to be meas- ured. Then the eye-lenses are separated till each is opposite to its own ob- ject. The frame containing the webs and their micrometer screws is then slidden into its place; and, the webs having been separated nearly to their proper distance by their free motion in the frame, they are placed precisely on the objects by their fine screws, the observer's eye being carried rapidly from one eye-lens to the other a few times, till he is satisfied of the bisection of each of the objects by its own web. The frame is then removed for read- ing off the measure by means of an achromatic microscope, on the stage of which it is placed. One of the webs is brought to the intersection of cross- wires in the eye-piece of the microscope; and by turning a screw, the revo- lutions of which are counted, the frame travels before the microscope, and the other web is brought to the intersection of the cross-wires. The parts of a revolution are read off by a vernier from a large divided circle attached to the screw. The advantages arising from the peculiar construction of this micrometer are the following: ] . Distances can be observed with great ac- curacy up to about one degree, and the angles of position also. 2. The Avebs, being in the same plane, are free from parallax, and arc both equally distinct, however high the magnifying power may be. 3. The webs are also free from distortion and from color. 4. A different magnifying power may be used on cadi of the objects; which may be advantageous in comparing a faint comet with a star. DRAWINQ FROM RELIEF MODELS. At the last meeting of the British Association, Captain Cybulz, of the Austrian army, called attention to a set of models intended to facilitate instruction in the manner of delineating the features of the ground on topo- graphical maps, and lately introduced into the technical schools of Austria. It is the first aim of the author to lead the pupil, by means of these models, to a correct understanding or appreciation of form, as the only way of pro- ducing a first-rate topographical draftsman. Instead, therefore, of setting him to imitate drawings from paper, his studies and copies will be made from models, and, at a more advanced stage, from nature itself. These models represent, firstly, inclined planes or slopes, separate, in combination, or inseeting each other. It is from these the pupil acquires the first idea of the principle upon which depends a correct delineation of the ground. 08 ANNUAL OF SCIENTIFIC DISCOVERT. Secondly, we have three models, which represent the most characteristic and most widely distributed features of the ground. Having acquired from, the preceding a thorough knowledge of fundamental principles, the pupil will proceed to delineate upon paper the following models. These represent, firstly, an undulating country; secondly, a plateau formation, with deeply- cut valleys; thirdly and fourthly, some mountainous tracts. Contour lines have been laid down upon the whole of these models with mathematical accuracy. The horizontal projection of some of the most difficult sections has also been added, to illustrate the manner of filling up the contour lines and laying down auxiliary contours. It has not, however, been thought advisable to do more, as otherwise the pupils would avail themselves of these facilities to too great an extent. A small instrument for measuring the gradients, and a scale showing the intensity of the shading (hachorres) for various degrees of acclivity, are to be made use of in copying the models. The author believes that the use of models, judiciously selected, will engage the pupil's uninterrupted attention ; he will overcome mechanical difficulties with greater facility, and will not be so wearied as by the tedious, but abor- tive, and, in reality, useless attempts to copy a topographical drawing placed before him. The author would add, that his models are made of galvano- plastic copper, and are therefore not so liable to breakage as plaster-of-Paris models. THE INDIA-RUBBER ARTIST. We have all of us laughed at the grotesque appearance made by toy heads of vulcanized India-rubber. A little lateral pressure converts its physiog- nomy into a broad grin, whilst a perpendicular pull gives the countenance all the appearance that presents itself when we look into the bowl of a spoon held longways. The pressure removed, the face returns to its normal con- dition. Of the thousands of persons who have thus manipulated this play- thing, it perhaps never struck one of them that in this perfect mobility lay the germ of a very useful invention, destined to be, we believe, of great prac- tical value in the arts. If we take a piece of sheet vulcanized India-rubber and draw a face upon it, exactly the same result is obtained. This fact, it appears, struck an observant person, and out of his observation has sprung a patent process, worked by a company under the name of the "Electro Printing-Block Company," for enlarging and diminishing at pleasure, to any extent, all kinds of drawings and engravings. It must be evident that if a piece of this material can be enlarged equally in all directions, the different lines "of the drawing that is made upon it in a quiescent condition must' maintain the same relative distance between each other in its extended state, and be a mathematically correct amplification of the original draft. The material used is a sheet of vulcanized India-rubber, prepared with a surface to take lithographic ink; this is attached to a movable framework of steel, which expands by means of very fine screws. On this prepared surface lines are drawn at right angles; these are for the purposes of meas- urement only. The picture to be enlarged is now printed upon its face in the usual way; and supposing it is to be amplified four-fold, the screw framework is stretched until one of the squares formed by the intersection of the lines measures exactly four times the size it did while in a state of rest. It is now lifted on to a lithographic stone, and printed, and from the impression copies are worked off in the usual manner. If the picture has to be worked with type, the enlarged impression has of course to be made MECHANICS AND USEFUL ARTS. 69 from 1>lork plates, the printing lines of which stand up like those of a wood- cut. This is accomplished by printing the picture, with prepared ink, upon a metal plate; the plate is then subjected to voltaic action, which cats away the metal, excepting those parts protected by the ink. Where it is required to make a reduced copy of a drawing, the process is inverted; that is, the vulcanized India-rubber sheet is stretched in the frame before the impression is made upon it. It must be evident that, on its being allowed to contract to its original size, ifc will bear a reduced picture upon its surface, from which the copies are printed. The application of this art to map-work is very apparent. Let us instance the ordnance maps. Both enlargements and reductions of the original scale on which they were drawn have been made in the ordinary way at an enor- mous expense, the greater part of which might have been avoided had this process been known. As it is, we have gone to work in a most expensive manner. The survc} 7 for the whole of England was made on the very small scale of one inch to the mile for the country, and of six inches to the mile for towns, and now there is a cry for an enlarged scale of twenty-five inches to the mile. In other countries, comparatively speaking, poor to England, this scale has been far exceeded. For instance, even poverty-stricken Spain is mapped on the enormous scale of as many as sixty-three inches to the mile. But with this question we have nothing to do; our purpose is only to show that it would be a great saving if the twenty-five inch scale had been originally carried out, as with this new process all the smaller scales could have been produced with perfect accuracy from this one at a very small cost. , Indeed, the public could, if they wish, have pocket fac-simile copies of that gigantic map of England and Scotland on the twenty-five inch scale, which, according to Sir M. Peto, would be larger than the London Docks, and would require the use of a ladder to examine even a county. The new art is applicable to engravings of every kind; and, moreover, it can very profitably reproduce type itself in an enlarged or reduced form. This is a fact of great importance to all Bible societies; for enormous sums are spent in producing this work in all imaginable sizes. But, it will be askecl, what advantage does this method present over a resetting of the page in the usual manner? Two very important ones speed and price. Let us suppose, for instance, that we wish to make a reduction of a royal octavo University Bible to a demy octavo. The price of resetting the type alone would be 800, and the "reading for corrections" another 300 at the least. Now, an identical copy could be produced by the process employed by the Company for 1'20; there would be no charge for " reading," as the copy is a fac-simile. Where there are many rules, marginal notes, and different kinds of types, as in Polyglott Bibles, the advantage of reproducing by the India-rubber process would be, of course, proportionately greater. We may mention another power possessed by the new method, which will prove very valuable to publishers. It sometimes happens that when a new edition of a work .is called for, some of the original blocks, or stereo- typed impressions, are found to be wanting. Heretofore new drawings and engravings would have to be made; but now, all this difficulty is obviated by simply taking the engraved page out of the old book, and reproducing the block required from it. This actually occurred with respect to the well- known work "Bell on the Hand," the missing blocks of which have been 70 ANNUAL OF SCIENTIFIC DISCOVERY. reproduced from some old printed pages. It is scarcely known yet how many centuries may elapse ere the ink of old books becomes so dry that it cannot be transferred by the new process; but it is quite certain that a couple of hundred years does not so far dry it as to render it incapable of giving an impression, so that we may have the earliest folio copies of Shak- speare's plays reproduced with exactness, in more available sizes, through the medium of a few sheets of India-rubber. Once-a- Week. COPYING-PAPER. Copying-paper, into the body of which a certain proportion of protosul- phate of iron (copperas) has been introduced, either during the manufacture or afterwards, by passing it between rollers covered with felt impregnated with a solution of salt, is much more advantageous in use than the com- mon paper. A letter written with common ink containing an infusion of nutgalls, or having the tanno-gallate of iron for its base, and covered with the above copying-paper, gives, by means of the press, a perfect fac-simile. If a little sugar or pro-gallic acid is added to the ink, a good copy may be had by pressing lightly the copying-paper upon the latter without the use of the press, taking only the precaution to interpose between the hand and the sheet of copying-paper another sheet of oiled paper, over which the rubbing must be done. Cosmos. NEW METHOD OF PRINTING MUSIC. A new method of engraving and printing music has been introduced at Paris. It is analogous to the method of carving wood by burning the pat- tern in. The music is stamped into blocks of wood with heated stamps, which have a shoulder to insure their penetrating to an equal depth. From this block a stereotype cast is taken. An edition of fifteen hundred copies, if stereotyped and printed by this method, is said to cost only about one- third as much as if engraved and printed from the engraved plate. S. W. FRANCIS' WRITING-MACHINE. This machine is placed in a neat, portable writing-case, about two feet square and ten inches deep, which may be carried about and used on any ordinary table. It is worked by means of keys placed on a key-board like those of a piano, each key representing a letter of the alphabet, and each letter producing its impression at a common centre. An endless narrow tape stretches the full length of the " bed " of the machine, passing over a small roller at either end, and uniting underneath. This tape is saturated with the ink. Directly in the centre of the " bed," and under the tape, is a circular hole of one inch diameter. Over this hole, and under the tape, on a car, a sheet of paper is placed;, then a sheet of tissue paper directly over it, leaving the tape between the two sheets of paper. A delicate frame then falls upon the paper, which keeps it in place, and moves while the printing progresses. A short steel rod then falls from a suspended arm, so as to present a flat surface, or platin, in the centre, directly over the paper. The lids being raised from the keys, they are played upon as in a piano, each being let- tered from A to Z, with the various punctuation marks, etc. The numbers MECHANICS AND USEFUL ARTS. 71 are represented by letters, as CVIII. for one hundred and eight, and so on, and the capitals are designated by a single dash at the top of the requisite letter. Each key, when struck, acts upon an independent lever within the machine, attached to a little elbow and arm, on the end of which is the corresponding letter-type, which now strikes the under sheet of paper and presses against the platin on the suspended steel rod, so that, the inked tape being between the two sheets of paper, the blow leaves the letter printed on each, namely, on the upper side of the lower sheet, and, of course, on the lower side of the upper, when brought in contact with the tape. As the printing goes on, the paper moves steadily to the left; and when the line is within four letters of its end, a little bell rings spontaneously to notify the writer that he must touch a spring which pushes the sheet up the .space of one line, and back, to begin again; and as the printing of the new line goes on, the paper travels back another line; and so on, till the page is completed. The letters can be formed of any sized type, engraved for the purpose, and suiting the taste of the purchaser. Those who use this " "Writing Printer" will be enabled to strike off two copies in less time than is re- quired to produce one with the pen; and for clergymen, merchants, editors, and literary men, it must prove of great value. The price of the machine is one hundred dollars, which is as cheap as a good sewing-machine, while the art of working it is not more difficult. The inventor is S. W. Francis, of New York City. ON THE INFLUENCE OF SCIENCE ON THE ART OF CALICO PRINTING. The following lectures on the progress of calico printing are communicated to the London Engineer by Prof. F. Grace Calvert, F. R. S. Pencilling and Block Printing. During the early part of this century, the production of designs upon calico were performed by means of hand-blocks, made of sj^camore or pear-tree wood. The face of the block was either carved in relief into the desired pattern, like ordinary wood-cuts, or the fig- ure was formed by the insertion, edgewise into the wood, of narrow strips of flattened copper wire, and the patterns were finished by the hand labor of women, with small brushes called pencillings. Owing to a strike amongst the block printers, in 1815, to resist the threatened introduction of machin- ery, great efforts were made on the part of the employers to render them- selves independent of hand labor; and the result has been the gradual introduction of cylinder printing. Engraving. The first kind of roller used was made by bending a sheet of copper into a cylinder, soldering the joint with silver, and then engrav- ing upon the continuous surface thus obtained. The second improvement consisted in producing the pattern on copper cylinders obtained by casting, boring, drawing, and hammering. In this case, the pattern is first engraved in intaglio upon a roller of softened steel of the necessary dimensions. This roller is then hardened, and introduced into a press of peculiar construction, where, by rotary pressure, it transfers its design to a similar roller in the soft state, and the die being in intaglio, the latter, called the "mill," is in relief. This is hardened in its turn, and, by proper machinery, is made to convey its pattern to the full-sized copper roller. This improvement alone reduced the cost of engraving on copper 72 ANNUAL OF SCIENTIFIC DISCOVERY. rollers many hundred per cent., nncl, what is of far greater importance, mule practicable an infinite number of intricate engraving which could never have been produced by hand labor applied directly to the roller. A further improvement was made by tracing with a diamond en the copper roller, covered with varnish, the most complicated pattern?, by means of eccentrics, and then etching. The combination of mill engraving with the tracing and etching precedes naturally followed, adding immensely to the resources of the engraver and printer in the production of novel designs. Another development of this art is the tracing of patterns on the surface of rollers, which has been effected by machines constructed on the principle of the pentagraph. Although this invention dates from 1834, still it is only of late years that it has been successfully applied. But if mechanical art has greatly assisted the engraver, chemistry has rendered him equally important services, by enabling him to abandon costly and cumbrous modes of impressing by force the designs on the cylinder, substituting for them a great number of etching processes. By some of these processes, as by every other addition to the resources of the engraver, an entirely new and beautiful class of engraving is produced, unattainable by any other known means. A very recent improvement is highly interesting in a scientific point of view. It is the application of galvanism to the diamond tracer. By com- bining the galvanic action with the eccentric motion, most beautiful and delicate engravings can be produced. This is effected by tracing the pat- tern with a varnish on a zinc cylinder, which is so placed in the engraving machine that, as a needle passes over its surface, and comes in contact with the zinc, the galvanic current is established, and, by simple machinery, causes the diamond to trace the corresponding pattern on the copper roller. The- communication is so rapid and so precise, that this invention of Sir. Gaiffe, of Paris, bids fair to produce very important results. Galvanism is also made use of for producing effects on roller surfaces by depositing copper thereon. To give an idea of the extraordinary influence which the introduction of machinery and improvements in engraving have had in cheapening the cost of printed calicoes, I may state that large furniture patterns, such as arc required for Turkish, Egyptian, and Persian markets, into which sixteen. colors and shades enter, would have cost formerly from thirty to thirty-live shillings per piece, because they would have required sixteen distinct appli- cations of as many different blocks, and would have occupied more than a week in printing, where the same piece can now be printed in one single operation, which takes three minutes, and costs five or six shillings. So rapid is the progress of one branch of manufacture in connection with another, that it has only recently been possible to produce the rollers capa- ble of performing this operation, that is to say, cylinders of copper forty- three inches in circumference by forty-four inches long. For light styles of printing, the time required to print a piece of thirty-six yards is not more than one minute. Chemistry. But the discovery which has exercised more influence than any other on the progress of calico printing is the application of chlorine gas as a bleach in- agent. Previously to the employment of this gas (chiefly as bleaching powder), the imperfect bleaching of a piece of calico required six weeks; and as it had to be exposed to the action of the atmosphere, a MECHANICS AND USEFUL ARTS. 73 large surface of land was required. Further, at that time, bleachers had to use potashes imported from Canada; whereas, at the present time, thanks to the progress of chemical knowledge, not only is soda-ash manufactured in this country, but, by the application of bleaching powder, calicoes are much better bleached in twenty-four hours than they were formerly by a six weeks' exposure to the atmosphere; and even when an extra cleaning and whiteness are required, as for madder goods, only two days are necessary. The aid of machinery renders possible the continuous process, that is to say, several hundred pieces of gray calico are sewn together, end to end, and made to pass from one operation to another, without any pause, until they are bleached. So rapid and economical is this method that the cost of bleaching a piece of calico does not exceed one or two pence. Chlorine, again, renders a great service to the calico printer, by enabling him, after his madder goods have been produced and soaped, to obtain fine whites without the necessity of exposing them for several days in the meadows to the action of the at- mosphere. In fact, the discovery of garancine and alizarine, and their appli- cation to calico printing, have facilitated the production of madder styles at very low cost, as the whites of such goods require no soaping, and only a little bleaching or cleaning powder. Cotton has this peculiarity, as distinguished from wool and silk, that it will not fix any organic color, excepting indigo, without the interposition of a mordant, which is generally a metallic oxide or salt. The two most impor- tant discoveries in connection with this necessity of calico printing were, first, that made in 18:20, by Mr. George Wood, of Bankbridgc, who found out the means of preparing calicoes with peroxide of tin, which enabled printers to produce a large variety of prints called steam goods; and, sec- ondly, that of Walter Crum, Esq., F. R. S., who, in a paper presented to the British Association, at Aberdeen, in 18-59, showed that the tedious process of ageing madder mordants for three or four days might be dispensed with by passing the goods, during a quarter of an hour, through a moist atmosphere, at a temperature of 80 to 100, where the mordants absorb the required quantity of moisture, and then rapidly undergo the chemical changes neces- sary to fit them for producing the black, purple, lilac, red, pink, and choco- late colors, which the madder root will yield immediately in the dyebeck, according to the nature of the mordant previously fixed in the cloth. As it is impossible in the brief space of an hour to convey an idea how va- rious colors are produced on prints, I shall confine my remarks to illustrating the interesting fact that abstruse science has brought to light various tub- stances which have lately proved valuable accessories to the resources of the calico printer. Thus Dr. Prout, some thirty or forty years ago, made the curious discovery that uric acid possessed the property of giving a beautiful red color, when heated with nitric acid, and then brought into contact with ammonia. The substance thus obtained was further examined by Messrs. Liebig and Wohler, in a series of researches which have been considered as amongst the most important ever made in organic chemistry; and this sub- stance they call murexide. In the course of these investigations they also discovered a white crystalline substance, called alloxan. For twenty years both these substances were only to be found in the laboratory; but in 1851, Dr. Saac observed that alloxan, when in contact with the hand, tinged it red. This led him to infer that alloxan might be employed to dye woollens red; and further experiments convinced him that if woollen cloths were prepared with peroxide of tin, passed through a solution of alloxan, and then sub- 7 74 ANNUAL OF SCIENTIFIC DISCOVERY. mitted to a gentle heat, a most beautiful and delicate pink color resulted. Subsequently, murexide was employed and applied successfully by Mr. De- pouilly, of Paris, to dyeing wool and silk, and to printing: calicoes, by the aid of oxide of lead and chloride of mercury as mordants; but the great obstacle to its extensive use was the difficulty of obtaining uric acid in suffi- cient quantity for its manufacture. The idea soon occurred to chemists to extract it from guano; and this is the curious source whence the chief sup- ply of uric acid is obtained, and which enables Edmund Potter, Esq., and other printers, to produce the color called Tyrian purple. Another example will be found in the successive scientific discoveries which have led to the discovery of the recently popular color, mauve. Lichens, which have been the subject of extensive researches on the part of Robi- quet, Heeren, Sir Robert Kane, Dr. Schunck, and especially of Dr. Stenbouse, have yielded to those chemists several new and colorless organic substances, which, under the influence of air and ammonia, give rise to most brilliant colors, and amongst these are orchil and litmus. Dr. Stenhouse, in a most elaborate paper published by the Royal Society in 1848, pointed out two im- portant facts : first, that the color-giving acids could be easily extracted from the weed by macerating it in lime- water, from which the coloring matters were easily separated by means of an acid; and, secondly, the properties of certain coloring acids, which gave M. Marnas, of Lyons, the key which ena- bled him to produce commercially from lichens a fast mauve and purple, which, tip to 1857, had been considered impossible of attainment. The commercial production by Mr. W. H. Perkin of another purple at the same time is not less interesting. Some thirty or forty years ago, Dr. Runge obtained from coal-tar six substances, amongst which was one called kyanol, which substance was thoroughly examined by Dr. Hoffman, who proved it to be an organic alkaloid, and identical with a substance known as aniline. Owing to the subsequent study of this substance by this chemist, and the discovery that it yielded a beautiful purple color when placed in contact with bleaching powder, his pupil, Mr. Perkin, was induced to make experiments with a view of producing commercially a fast purple, in which he succeeded. The process devised by this chemist is exceedingly simple, and consists in oxidizing aniline by means of bi-chromate of potash and sulphuric acid. More recently, M. Renard found a method of producing also from aniline, by means of chlorine compounds, a most splendid rose color, called by him fuchstachine; and within a few months Mr. Price has also succeeded in pro- ducing from aniline, by the employment of peroxide of lead, either a fast purple, or a pink, called by him roseine, and a fast blue, according to the mode of operating. All these colors require special mordants to fix them on calicoes or muslins, such as albumen, lactarine, and other azotized principles. In concluding, I cannot give a better idea of the immense magnitude of the calico-printing trade of Great Britain, than by quoting the number of yards exported, which amounted in 1858 to nearly eight hundred millions. MINIATURE AND ENAMEL PAINTING. Painting in miniature is in danger of becoming one of the lost arts. Pho- tography has been carried to such a degree of perfection, is so accurate as to mere likeness, and is, withal, afforded so cheaply, that it is rapidly taking the place of portraits upon ivory. Artists who have hitherto devoted them- selves to this branch of the art are now either turning their attention to MECHANICS AND USEFUL ARTS. 75 painting upon canvass, or find employment as finishers of the photographic miniatures. To this, indeed, is owing, in a large measure, the satisfaction which the photographs give, for something of the value of the old miniature in colors is retained where the work is skilfully done, and the inevitable faults of the instrument are, in some degree, corrected. The following historical sketch of the art, which seems thus to be going out, and of enamel painting, which photography is also in some degree supplanting, is instruc- tive and entertaining. Miniature painting, since the invention of printing superseded the art of the calligrapher and illuminator, has been confined principally to portrai- ture, and the ancient vellum has been discarded for ivory and enamel. Ivory is preferred for the soft semi-transparency of its texture, which communi- cates a peculiar delicacy to the colors, especially the carnations or flesh tints. The ivory being cut in thin sheets, i-equires however, on account of this property, something perfectly white and not liable to tarnish, at the back, to serve as a foil; otherwise the effect of the painting might be quite de- stroyed by the darkness of the surface behind showing through. Ivory and enamel being quite smooth, and without textui'e or absorbency, it is impos- sible to spread a flat tint. With the most dextrous handling, a little heap of color will collect where the brush first touches or leaves the surface, and the intervening space, which it may have been intended to cover with an even " wash," will present something of the irregularity of a flow of water on a greasy plate or polished table. Hence it becomes necessary to fill up the interstices of these irregularities with hatchings and stipplings. The point and steel scraper are both used, to more rapidly procure the desired gradation, as well as to obtain mechanical regularity in the stippling, which has been much sought for, particularly by French artists. It is true that the labor thus involved may be avoided in certain parts by the use of body- colors that is to say, colors rendered opaque by the addition of white. But body-color washes, from their unmanageable nature on ivory, can only be used in portions which can be covered at once, or do not require much finish, such as backgrounds and draperies; and here the surface of the ivory is of course sacrificed. Body-color applied in this way will give an even, flat gradation in a background, and impart a cloth-like effect to the representation of the modern male costume; but from the difficulty of calcu- lating when "wet" the difference of tone the body-color will assume when dry, it is useless for flesh painting, if spread in coats so as to cover the ivory. Opaque and semi-opaque pigments, of earthy and mineral extraction, were, we know, used in the flesh by the ancient painters on vellum; but then they were lightly stippled, not loaded; and such pigments may be worked trans- parently in the same way on ivory, though the modern miniature painters prefer the more transparent colors. Where body-color, therefore, is laid on in certain parts, so as to cover the surface, and the ivory shows through in other portions, the work can scarcely be harmonious. For this reason the use of body-colors, which were extensively and are still employed by French miniature painters, has been discontinued by the English artists of the pres- ent century. Gum-water is the only vehicle besides simple water employed with the transparent or body colors. The large size of modern miniatures may excite some curiosity as to how a sheet of ivory can be obtained so much larger than the diameter of the largest elephant's tusk, especially when it is known that the sheet is not joined, as might be supposed. The tusk is simply sawn circularly in other 76 ANNUAL OF SCIENTIFIC DISCOVERY. words, round its circumference; the ivory is then ?tcnmed, nnd flattened under hydraulic pressure, and finally mounted with caoutchouc on a mahog- any panel. Enamel painting has the great recommendation of being perfectly inde- structible. Specimens of this art applied to pottery are now in existence which have not changed their hues during three thousand years. The enamel tints on Egyptian idols, scarabei, necklaces, etc., are precisely sim- ilar to the colors now produced by the enameller. The difficulty of hand- ling the brush is quite as great as in painting on ivory. But a far greater technical difficulty is that of calculating the exact effect of the process of firing the enamel, in altering the hues of the several applications of color. Fine coloring is therefore rai-ely found in enamels. Moreover, the enamel painter's list of pigments is limited to those prepared from metallic oxides, and many metals are perfectly useless on account of the high degree of heat to which enamel paintings are subjected. Modern science has, how- ever, done much to supply this deficiency. The colors are mixed with oil of spike or lavender, or with spirits of turpentine. These essential oils volatilize rapidly under the effect of heat, but the fixed oils would cause the enamel to blister. The ordinary brushes of the painter in water colors are used. We extract the following valuable remarks on enamel painting, and account of the process employed by the artists of the present day, from a communication to the Art Journal., in 1859, by an enamel painter of reputa- tion. He says : " Pictures in enamel of any importance as works of art have been very rarely produced until within the last eighty or ninety years'; for, although Petitot, in the reign of Louis XIV., drew with exquisite neat- ness, he seldom produced enamels which aimed at more than microscopic finish and accurate drawing of the human head. His works generally measure from about an inch and a half to two inches in diameter, and are usually either circular or oval. It was reserved for modeni times to try a bolder flight, and the result has been that enamel paintings are now pro- duced with every possible excellence in art. The rich depth of Rembrandt and Reynolds can be perfectly rendered, together with ail their peculiarities of handling and texture; and the delicacy of the most beautiful miniature of ivory may be successfully competed with. As regards size, enamels are now painted measuring as much as sixteen inches by eighteen, and fifteen inches by twenty. The kind of enamel used for pictorial purposes is called 'Venetian white hard enamel;' it is composed of silica, borax, and oxide of tin. The following is a brief description of procedure in the art of enameling: " To make a plate for the artist to paint upon : A piece of gold or copper (usually gilt) being chosen, of the requisite dimensions, and varying from about an eighteenth to a sixteenth of an inch in thickness, is covered with pulverized enamel, and passed through the fire until it becomes of a bright white-heat; another coat of enamel is then added, and the plate again fired; afterwards a thin layer of substance called flux is laid upon the surface of the enamel, and the plate undergoes the action of heat for the third time. It is now ready for the painter to commence his pictm-e upon. ' Flux' partakes of the nature of glass and enamel: it is semi-transparent, and liquefies more easily in the furnace than enamel. When flux is spread over a plate, it imparts to it a brilliant surface, and renders it capable of receiv- ing the colors; every color, during its manufacture, is mixed with a small MECHANICS AND USEFUL ARTS. 77 quantity of flux; thus, when the picture is fired, the flux of the plate unites with the flux of the color, and the coloring pigment is perfectly excluded from the air by being surrounded by a dense vitrified mass. From this will be understood the indelible and we might almost say eternal nature of enamel. " The plate undergoes the process of firing after each layer of color is spread over the whole surface. This process corresponds to the drying of the pigments in oil or water-color painting before the artist ventures to retouch his work. Sometimes highly-finished enamel requires fifteen or twenty firings. Great care must be taken to paint without errors of any kind, as the colors cannot be painted out or taken off, as in water or^il, after they have once been vitrified, without incurring excessive trouble and loss of time. If the unfortunate artist miscalculates the effect of the fire on his pigments, his only alternative is to grind out the tainted spot with pounded flint and an agate muller; and so hard is the surface, that a square inch will probably take him a whole day to accomplish." THE IVORY TRADE. The principal source of supply of ivory is Africa much of it coming from the interior by way of Egypt and the Nile. Until within a few years the Egyptian pashas made trading up and clown the Nile a monopoly ; now, Egyptian, French, German, and English merchants explore the remote re- sources of the river, not for the purposes of science, but for those of com- merce. In the last report of sales of ivory in London, the head-quarters of this traffic, we find that eighty -five thousand pounds of the ivory sold was " Egyptian ; " that is, found its way to civilization through Egypt. That Africa was the source whence the ancients of southern Europe drew their supply, we learn from Pliny the Younger, who says that the vast con- sumption of ivory for articles of luxury compelled the Romans to seek for it in another hemisphere, " as Africa had ceased to furnish elephants' tusks except of the smallest kind." After the overthrow of the Roman Empire, the commerce between Europe and Africa was suspended for centuries. At length the enterprise of Portu- gal, the eldest daughter the Lusitania of Rome, opened anew Africa and. India. In the meantime, the lordly elephant had multiplied in his native forests, and if the long tusks were secured by the natives, they served merely the plebeian purposes of door-posts, or the defences of wooden idols. Battell, a quaint old Englishman, who served in the early Portuguese armies, says that the Africans "had their idols of wood, fashioned like a negro, and at the feet thereof was a great heap of elephants' teeth, containing three or four tons of them." It is a well-known fact that the inhabitants of Angola and Coniro, when the Portuguese first occupied those coasts, were found to have preserved an immense number of elephants' teeth, the accumulation of cen- turies. For a long time this ivory was exported in vessels of Portugal to various parts of Europe ; and this traffic formed one of the most lucrative branches of the early modern trade with Africa. About the middle of the seventeenth century this store became exhausted, and the sons of Ethiopia were instigated to imitate their ancestors in renewing the battle with the wide- eared, long-tusked Elephas Africamis. To-day, the amount of ivory consumed in the workshops of Europe, America, and India, is immense; and yet, great as it is, the continent of 7* 78 ANNUAL OF SCIENTIFIC DISCOVERT. Africa furnishes seven-eighths of all that is worked up into ornaments, toys, and crucifixes in France; heathen gods, boxes, and fans in India and China; billiard-balls, boxes, miniature plates, chessmen, mathematical rules, keys for piano-fortes, organs and melodeons, fans, combs, folders, dominoes, and a thousand and one other things, in England, Germany, and the United States. Portugal Avas the England of the sixteenth century in more respects than one. For two centuries Portugal held, in the East and on the African coast, the power and influence now in the hands of England. Lisbon at that time was the head of the ivory market; now London is the mart \vhere ivory- dealers most ck> congregate. It sometimes occurs that the Salem and other American merchants engaged in the African trade ship their tusks or teeth, in commercial parlance to London after they have brought them from the Zanzibar and Mozambique coast to the United States. In the world's great metropolis there occurs at regular intervals one of those sales which furnish the manufactures with their stock of elephants' teeth. While we associate ivory and India together, but very little of the former comes from the latter. It is estimated that to supply ivory to the British market for the last few years, it has required about 1,000,000 Ibs. annually. Of this quantity, Ceylon, the great elephant park of India, furnishes only 500 or 600 tusks. The ivory which is put down in the printed reports of sales as " Bombay," in nine cases out of ten is shipped by Mohammedan mer- chants from the east coast of Africa to the large north-western commercial emporium of Bombay. We do not mean, however, to assert that no ele- phants' tusks come from Asia; for occasionally there will be small lots come from Ceylon and Sumatra. There is also a large ivory trade between Zanzi- bar and China, via Bombay. A great deal of ivory, we may state, by the way, now reaches the United States directly from Africa. The immense demand for elephants' teeth has of late years increased the sup- ply from all parts of Africa. At the end of the last century the annual aver- age importation into England Avas only 102,500 Ibs.; in 1827 it reached 364,784 Ibs., or 6,080 tusks, which would require the death of at least 3,040 male ele- phants. It is probable that the slaughter is much greater, for the teeth of the female elephant are A'ery small ; and Burchell tells us, in his African traA r - els, that he met with some elephant-hunters who had shot tAvelve huge fel- lows, Avhich, however, altogether produced no more than 200 Ibs. of ivory. To produce 1,000,000 Ibs. of ivory, the present annual English import, we should require estimating each tusk at 60 Ibs. the life of 8,333 male ele- phants. It is said that 4,000 tuskers suffer death every year to supply the United States Avith combs, knife-handles, billiard-balls, etc. etc. A tusk Aveighing 70 Ibs. and upAvards is considered by dealers as first-class. Cuvier formed a table of the most remarkble tusks of which any account has been given. The largest on record Avas one which Avas sold at Amsterdam, which weighed 350 Ibs. In the late sales at London, the largest of the " Bom- bay and Zanzibar" was 122 Ibs. ; of " Angola and Lisbon," 69 Ibs.; of "Cape of Good Hope and Natal," 106 Ibs.; of " Cape Coast Castle, Lagos," etc., 114 Ibs.; of "Gaboon," 91 Ibs.; "Egyptian," 114 Ibs. But it must not be inferred from this that large tusks are noAV rare. On the contrary, it is probable that more long and heavy teeth are noAV brought to market than in any preA'ious century. A short time ago Julius Pratt & Co. cut up, at their establishment in Meri- den, Ct., a tusk that Avas nine and a half feet long, eight inches in diameter, MECHANICS AND USEFUL ARTS. 79 and which weighed nearly two hundred pounds. The same firm, in 1851, sent to the World's Fair, London, the widest, finest, and largest piece of iyoiy ever sawed out. By machinery, invented in their own factory, they sawed out (and the process of sawing did the work of polishing at the same time) a strip of ivory forty-one feet long and twelve inches wide. It took the pre- cedence of all the specimens sent in by England, France, or Germany, and received rewarding attention from the Commissioners. The most costly tusks, or portions of the tusks, are those which are used for billiard-balls. What are termed " cut-points " of just the right size for billiard-balls, from 2j! to 2 inches in diameter, brought the highest price (25) per cut of any ivory offered in the London market at the late sales. Billiard-ball making has of late become a very important item of manufacture in this countiy. The teeth from the west coast, with the exception of " Gaboon," are less elastic and less capable of bleaching than those that come from other por- tions of Africa. The west coast tusks are much used for knife-handles. Since the French have possessed Algeria, France receives a considerable portion of ivory from Central Africa by the large caravans that travel from Timbuctoo northward. Ivory is also furnished by the walrus, or sea-horse, and commands a price equal to the best qualities of elephant ivory. It is, however, too hard and non-clastic for many purposes, and has the disadvantage of being too small to cut up profitably. NON-INFLAMMABLE FABRICS. In the long list of casualties that we are frequently called upon to read, appear too often the accounts of women and children burned to death by the ignition of their clothing. The frequency of these accidents is startling and painful, not only here, but in those countries where the same style and material in dress prevails. As these causes generally occur in consequence of an immediate contact with the burning coals of a grate or stove, it seems but just to conclude that the present mode of wearing extended skirts ren- ders the risk much greater, and increases the danger of a fatal sacrifice to fashion. Some of the garments of women are extremely inflammable, and these are worn so near to the person that it becomes next to impossible, in case of their ignition, to divest the wearer of them until she is seriously injured. This is particularly the case with the lighter materials of which party and evening dresses are composed; and this fact should impress itself upon the public mind here, as it has in England, where the Queen, a short time since, requested the Master of the Mint, Professor Graham, to super- intend a series of experiments with a view to determine if these fabrics could by easy means be rendered non-inflammable. The professor entrusted the inquiry to two distinguished chemists, Dr. Oppenheim and Mr. Versmann. From an article on the subject, contributed by Robert Hunt to the London Art Journal, we learn the prominent points of their report. They com- mence by stating some of the peculiarities of cotton and linen, and then enumerate the numerous articles which have been from time to time em- ployed and recommended by different parties to render them flame-proof, such as alum, borax, silicate and carbonate of potash, sulphate of iron, sul- phate of lime, the chloride of ammonium, and other salts of ammonia; but state that none of these experiments resulted satisfactorily. 80 ANNUAL OF SCIENTIFIC DISCOVERY. Experimenting upon the sulphate of ammonia, as recommended by Guy- Lussuc, they further state that a solution containing seven per cent, of the crystals, or sixty-two per cent, of anhydrous salt, is perfectly anti-flamma- ble, and add : " Tungstate of soda ranges among the salts which can be manu- factured on a large scale, at a cheap rate. A solution containing twenty per cent, renders the muslin perfectly non-inflammable. It acts, apparently, by firml}' enveloping the fibre, and thereby excluding the contact with the air. It is very smooth, and of a fatty appearance, like talc, and this prop- erty facilitates the ironing process, which all other salts resist." And again: "For all laundry purposes the tungstate of soda can only be recommended." The following formula is given as having proved efficacious, and will simplify the application : " A concentrated neutral solution of tungstate of soda is diluted with water to twenty-eight degrees Twaddle, an alkalio- mcter so called, and then mixed with three per cent, of phosphate of soda. This solution was found to keep and to answer well. It has been intro- duced into her Majesty's laundry, where it is constantly used." The solution can be applied to any fabric. It is only necessary to dip the cleansed article in the prepared fluid, and then drain and dry it, after which it may be ironed ; or, if preferred, the solution may be incorporated with the starch to be used in the stiffening. Although the above are not the only experiments that have been tried in Europe, yet they are, perhaps, the most successful, and the result should be accepted, and the advice followed, wherever these fabrics are used. The lightest materials, when submitted to this preparation, may char and shrivel, but they will not blaze. As the usual solicitude and warnings will not avert the fatal consequences, it would seem that the only method of saving life from ignition of clothing consists in wearing those articles only which have been steeped in this life- saving fluid. INTERESTING FACTS IN REGARD TO THE VALUE OF SEWING- MACHINES. In the recent contest before the Commissioner of Patents for the extension of Howe's patent for sewing-machines, the following facts were proved in relation to the value of the patent, which, at first thought, are certainly astonishing. Ezra Baker states that the amount of the boot and shoe business of Massachusetts is $55,000,000 annually, and the ladies' and misses' gaiter boot and shoe business is at least one-half of the whole boot and shoe busi- ness in that state; and is, therefore, equal to $27,500,000. He also states that about one-eleventh of these $55,000,000 is paid for sewing labor. From this proportion it appears that the annual sewing labor upon ladies' and misses' gaiter boots and shoes is $2,500,000, and that it would cost four times as much if done by hand; so that the annual saving by this inven- tion in the manufacture of ladies' and misses' boots and shoes in one state is $7,590,000. The price of these shoes has been reduced to the consumer one-half by the introduction of sewing-machines the price of material remaining the same. Oliver F. Winchester is a manufactm-er of shirts at New Haven, Conn. He says that his factory turns out about eight hundred dozen per week; that he uses four hundred sewing-machines, and that a machine, with an attendant, will do the work of five hand-sewers at least, and do it better. MECHANICS AND USEFUL ARTS. 81 He pays, at least, $4 per week; hut, reckoning it at S3, the old price for sewing before machines were introduced, it shows a saving, in this single manufactory, of 8240,000 a year. Allowing the males of the United States to wear out two shirts a year apiece, and a proportional saving would amount to $11,080,000 annually in making the single article of shirts. James W. Millar, connected with Brooks Brothers, of New York City, manufacturers of clothing, states that that house alone does a business of over $1,000,000 annually, and use twenty sewing-machines in the store, and patronize those that others use, and do about three-fourths of all their sew- ing by machines, and pay annually for sewing labor about $200,000; $7-3,000 of this is saved by machines; that is, the machines save $75,000 on every $200,000 paid for sewing labor. And he states that the house of Brooks Brothers does not make one-hundredth part of the machine-made clothing manufactured in New York. This, putting the proportion at one-hundredth part, would make the business of manufacturing machine clothing in the city of New York $100,000,000 annually; and, at the rate that house pays for sewing, it brings the cost of sewing in this branch of manufacture in the city of New York even with the assistance of the sewing-machines up to $20,000,000. A saving of $75,000 on every $200,000 of this makes $7,500,000. James McCall states an estimate of what proportion of the clothing business of the United States is done in the city of New York, and puts it at about one-tenth. Multiplying the cost of sewing in that business alone in New York, as shown above, by ten, it carries the extent of cost in the United States to $200,000,000 per annum; and assuming that as large a portion of this is done by machines in other places as is done in the city of New York, it makes the cost of sewing labor in this particular manufacture in the United States the above sum of $200,000,000; and this, too, by the assistance of machine sewing. $75,000 on every $200,000 of this is saving, which makes the saving in the United States amount to $75,000,000 annually in this branch alone. Scientific American. MAGIC RUFFLES. Ruffles have been worn from time immemorial; but " Magic Ruffles," or ruffles made by magic, are a modern invention. The old lady in her frilled cap, two generations ago, could hardly have believed that her granddaugh- ter would, by the assistance of mechanism and steam, be enabled to make ruffles at the rate of two yards a minute, and of more perfect workmanship than it is possible to produce by hand. Two inventors, of New York city, have recently devised an attachment to the sewing-machine, for the manufacture of ruffles, which bids fair to prove more valuable than any other of the four hundred patented improvements on the original invention. Through the combined genius of these hundreds of patentees, the sewing- machine had gradually approached perfection, until the variety of work to which it was adapted had nearly equalled that of the needle and thimble of the seamstress. Stitching, hemming, and cording were done with great ra- pidity, and even gathering was considerably expedited by its use; but in making ruffles, puffs, and many other kinds of gathered fabrics, the ordi- nary process, even with a sewing-machine, is a slow and tedious one, requiring much manipulation and great care. This last invention, however, renders tlvj process as simple and rapid as plain sewing. It has not yet been applied 82 ANNUAL OF SCIENTIFIC DISCOVERY. to family machines, but has been used by the proprietors for several months past in the manufacture of a new kind of ruffles for the market, which are applied to a great variety of uses. Except in its perfection and the uniformity of its gathers, the Magic Ruffle very nearly resembles the old article worn by our grandmothers; but on close inspection it is found to contain no gathering-thread, the gathers being confined by the same line of machine-stitching that holds it to the strip of cloth to which it is attached. The patent for this machine was granted in May, 18GO, since which time the manufacturing of the new ruffles has developed into a gigantic business; one company in New York turning out from ten to fifteen thousand yards of ruffling daily, while the orders for the goods are constantly in advance of the production. New York Tribune. PRINTING FABRICS IN IMITATION OF EMBROIDERY. M. Perrot, France, has recently discovered a novel mode of ornamenting fabrics, by the printing process, so as to produce an effect similar to embroi- dery. This process consists simply in printing, by the aid of rollers, any desired pattern upon a fabric, in a solution of gutta-percha, previously bleached by the aid of chlorine, and dissolved by any of the well-known solvents. The fabric so printed is then passed through a box or casing con- taining woollen, cotton, silk, or other fine flock or colored powder, which adheres only to those parts impressed with the solution, and forms beauti- fully raised patterns and devices, having a fine, soft, and velvety surface. CHINESE EMBROIDERY. Probably the finest modern examples of pure embroidery in silk, unmixed with gold and silver thread, pearls, or precious stones, are executed by the Chinese. Not only in execution, but in design and the fitness of the forms of the ornament to the material and purpose, the embroideries of the Chi- nese generally exhibit a great superiority to the usual examples of European skill. The extreme care taken with the work, especially in the more costly specimens, renders them very instructive examples of textile decoration. From seven hundred to seven hundred and fifty stitches may be counted in the space of a square inch. Some years ago I took the trouble to dissect some of the best examples I could meet with, and the more closely they were examined the more marvellous the work appeared. Mr. Wallis, Jour- nal of Society of Arts, London. NEW METHOD OF EMBOSSING WOOD. At a recent meeting of the Franklin Institute, Mr. Wood exhibited some specimens of wood embossed by his patent process. The wood is soaked in water, and then subjected to pressure under a metal matrix heated suffi- ciently to burn away the superfluous material. The wood is not finished at one operation, the matrix being removed several times in order to brush off the charred wood. The specimens possess more softness than is usual in wood carvings; and when varnished have a beautiful appearance. The design is first modelled in clay or wax, and a plaster cast taken from it; this serves as a pattern from which the matrix is moulded. The saturation MECHANICS AND USEFUL ARTS. 83 by water prevents the burning or charring of the material not immediately in contact with the metal. ARTIFICIAL WOOD. In a recent lecture at the Conservatoire des Arts et Metiers, M. Payen called the attention of his hearers to the process of making a kind of ebony, or artificial wood, very hard, very heavy, and capable of receiving a very high polish and a brilliant varnish. M. Ladry, the inventor of this process, takes very fine sawdust, mixes it with blood from the slaughter-houses, and sub- mits the resulting paste to a very heavy pressure obtained by the hydrau- lic press. If the paste has been enclosed in moulds it will take the form of the mould, and resembles pieces of ebony carved by a skilful hand. Another curious application of this paste consists in the formation of brushes. The bristles are arranged in the paste while yet soft; the paste is covered by a plate pierced with holes, through which the bristles pass; the pressure is then applied, and brushes are obtained, made of a single piece, cheaper and more lasting than the usual kind. This artificial wood of M. Ladry is much heavier than common Avoods. Cosmos. WHY THE SHOE PIXCHES. A pamphlet has lately appeared of peculiar interest to that vast multitude of our population who are the victims either of corns or of expensive corn doctors, and who suffer, as some poet has suggested, from a style of bunion which is not altogether conducive to " Pilgrims' Progress." It is translated from the German by a young Edinburgh physician, and published with the following title: " Why the Shoe Pinches; a Contribution to Applied Anat- omy. By Hermann Meyer, M. D., Professor of Anatomy in the University of Zurich. Translated from the German by John Stirling Craig. Edinburgh : Edmonston and Douglas." Dr. Meyer, the author, is pronounced one of the highest continental au- thorities on Physiological Anatomy, who has published an important gen- eral text on that science, as well as several treatises on the structure of the foot and knee. In the discussion now under consideration he has already been preceded by Peter Camper, who, in the last century, wrote a paper " On the Best Shoe," and who zealously but ineffectually urged that the foot-gear of man was quite as important a topic as the shoeing of horses, to which so much attention is given. Against the prevailing pattern, Dr. Meyer, in his capacity of anatomist, utters an earnest protest. The cut of a shoe, says the Doctor, is not, as the cut of a coat, a matter of indifference. " When Fashion prescribes an ar- bitrary form of shoe, she goes," he asserts, " far beyond her province, and, in reality, arrogates to herself the right of determining the shape of the foot." In his opinion the shoemaker ought not only to produce a shoe that docs not pinch, but a shoe so constructed that it will give to a foot distorted by the pinching it has borne already, a fair chance of a return to its right shape, and full possession of its power as a means of carrying the body onward. He tells us that, in measuring a foot for a shoe or boot, the first thing to be considered is the place of the great toe. Upon this toe, in walking, the weight of the whole body turns at every step; in the natural foot, therefore, 84 ANNUAL OF SCIENTIFIC DISCOVERY. it is in a straight line with the heel. A central straight line drawn from the point of the great toe to the middle of its root, if continued, Avould pass very exactly to the middle of the heel. By the misfitting hoot commonly worn, the point of the toe is pressed inwards, the root outwards. The practice adopted by many of having a last made of the exact size and model of the foot, is condemned by Dr. Meyer, if the foot has been pre- viously injured in consequence of wearing ill-fitting boots or shoes. If a cast be made of a distorted foot, and a boot fitted to that, it is bad, because thereby the distortion is confirmed. It would be much the better, therefore, says the Doctor, so to form the boot that the conditions of healthy walking are allowed for, and the bones, at least to some extent, can gradually right themselves. To a foot shortened by distortion he would fit a shoe adapted to its healthy size. But of a pair of boots made so as to content the eye of an anatomist, who knows what work is done by every bone, the main char- acteristic is, that when they stand side by side, with their heels in contact, the inner margins of the front part of the soles are along the whole edge corresponding to the sides of the great toes, also in contact. If it be desira- ble to point the toes, they must be pointed only from the outer side, after the place of greatest breadth in the foot has been properly respected. A certain sense of a turn inward belongs to the shape of boots so made, but if they fit perfectly they will insure to the foot the utmost ease and power; and, as their shape is of the ordinance of nature, they are no doubt really as elegant as those of which the pattern is a bootmaker's invention. Dr. Meyer says that two or three persons in Zurich have had their boots made on these principles without exciting special remark so immediately is the propriety of the change admitted even by the arbiters of fashion. As an evidence of its utility, a London journal mentions the fact that marching soldiers, who often break down in consequence of their shoes, would be rendered vastly more efficient if they were made in accordance with the structure of their feet. ATMOSPHERIC WASHING-MACHINE. At the last meeting of the British Association, Mr. J. Fisher called atten- tion to a new washing-machine, the action of which was derived from streams of air forced through water from below, the most effectual tem- perature of the water u^ed being about 140 Fahrenheit. It was stated that machines on this principle, driven by steam power, had been for some time in successful use, in manufactories in England, for cleansing soiled laces. IMPROVEMENT IX THE MANUFACTURE OF STARCH. A patent has recently been issued in England for submitting starch after it is deposited in the manufacturing process to the action of a hydraul ic press, in suitable boxes, so as to press all the water out, instead of evaporat- ing all the moisture in artificially heated rooms, according to the usual prac- tice. A great saving in fuel is thus effected by well-known and very simple means. NEWSPAPER ADDRESSING MACHINE. The following is a description of a newspaper addressing machine, in- vented by R. & D. Davis, of Elmira, X. Y., and recently introduced practi- cally in several of the large newspaper offices of New York. The machiu- MECHANICS AND USEFUL ARTS. 85 cry consists essentially of two distinct parts, one lettering the type or blocks with which the impressions are made, and the other doing the printing. The lettering machine consists of a disk, or wheel, about eight inches in diameter, on the periphery of which are lirmly-attached dies, representing the letters of the alphabet. By revolving this wheel or disk on its axis a die representing any desired letter is brought in position, and stamps its impress on a small block, when another letter is brought in position, and so on until the entire address is stamped, which is accomplished in about the same time required by a compositor to set the same number of types in a stick. A large number of these blocks, having been impressed with the addresses, are readily attached to a band, thus forming an endless belt of blocks. These belts are systematically arranged in boxes, so that any address may be referred to in a moment, for change or other purpose. When used, a belt is taken from the box and placed on the printing-machine ready for operation in a few seconds, when the impressions are made by a slight pres- sure with the foot, as rapidly as the papers or wrappers can be removed from the press. The entire apparatus is operated by hand, is simple, compact, cheap, requires no skill to work it, and is not liable to get out of repair, which renders it well adapted to papers of small as well as large circulation. MEASURING FAUCET. Whitman's measuring and registering faucet is simply a force-pump with a solid piston operated by a lever or crank. The cylinder is of the capacity of the unit of measure (pint, quart, etc.), and at each discharge an index on a dial-plate moves forward one degree. Mr. Whitman thinks this invention will supersede the use of funnels in grocery stores, abate the nuisance of flies about molasses casks, and detect frauds in the capacity of barrels. The faucet, made of cast iron, and capable of measuring quarts, is sold for four dollars. NEW GRINDING AND POLISHING APPARATUS. The Xew York Belting Company are now introducing a new form of emery wheel, which bids fair to supersede entirely the ordinary mode of covering a wheel with glue and sprinkling emery upon it. The emery is incorporated with India-rubber and sulphur, and while in a plastic state is put into moulds, and submitted, under great pressure, to a high degree of heat, according to Goodyear's patent for vulcanizing; this converts it into a solid granular mass, resembling granite or iron. It can be made of any desired grade of emery, and used either dry or with oil or water. The Avhcels can be turned off in a lathe, running very slow, in the same manner as iron is turned, which will enable parties using them to turn the face of the wheel to conform to work of any irregular shape, or to " true" them if necessary. NEW MODE OF JOINING PIPES. Mr. Siemens has exhibited at the London Institution of Civil Engineers a machine of his invention, manufactured by Messrs. Guest and Chrimes, for joining lead and other pipes by pressure only. The machine consisted of a strap of wrought iron, in the shape of the letter V, and of three dies, two of which were free to slide upon the inclined planes, while the third was 8 86 ANNUAL OF SCIENTIFIC DISCOVERT. pressed down upon them by means of a screw passing through a movable cross-head, embracing the sides of the open strap. The pipes to be joined were placed end to end, and a collar of lead was slipped over them. The collar was then placed between the three dies, and the pressure was applied by means of a screw-key until the annular beads, or rings, projecting from the internal surface of the dies, were imbedded into the lead collar. The ma- chine was then removed, and a joint was formed capable of resisting a hydraulic pressure of eleven hundred feet. The security of the joint was increased by coating the surfaces previously to their being joined with white or red lead. The advantages claimed for this method of joining lead or other pipes, over the ordinary plumber's joint, were the comparative facility and cheapness of execution, as the cost of a joint of this description was said to be only about one-third or one-fourth that of the plumber's joint. A machine of a similar description was also used for joining telegraphic line wires, a specimen of which was likewise exhibited by Mr. Siemens. BITUMENIZED PAPER PIPES. The ingenious idea of hardening paper by means of an admixture of bitumen under the influence of hydraulic pressure, so as to convert it into a substitute for iron, is due to M. Jalourean, of Paris. The world has already become familiar with the utility and value of papier maclie as a substitute for stone or marble in moulding, architectural castings, etc. It has also heard that the Chinese construct their cannon of prepared paper, lined with copper, and that they even make paper pipes; that an eccentric char- acter has built himself a house of paper, and that our American friends have invented a veritable paper brick; but nothing, it is believed, has lately come before the British public, in the way of paper, so curious, and yet practica- ble, as these bituminous paper pipes. Testing experiments, conducted at the Houses of Parliament, are reported to have " proved that the material, while it possessed all the tenacity of iron, with one-half its specific gravity, had double the strength of stoneware tubes, without, moreover, being liable to breakage, as in the case of other material, and which frequently causes a loss to the contractor of some twenty or twenty-five per cent, on the sup- ply." In order to test their strength, two of these bituminous paper pipes, of five-inch bore and half an inch thick, were subjected to hydraulic power, and they are said to have sustained, without breaking or bursting, a pressure of two hundred and twenty pounds to the square inch, or equivalent to five hundred and six feet head of water. The cost of the pipes is understood to be about one-half the cost of iron. London Builder. GAS METERS. "We make the following extract from the annual report of John C. Ores- son, the engineer of the Philadelphia Gas Works : Among the many subjects of a practical character that engage the atten- tion of the gas engineer, none has given rise to more solicitude than the choice and management of gas meters, upon the accuracy and unvarying action of which the interests of both consumer and producer are in a great degree dependent; the former for his fair and uninterrupted supply of the commodity he pays for, and the latter for securing the due returns for his outlay of material and labor. All these desirable results are obtained in MECHANICS AND USEFUL ARTS. 87 great perfection from the instrument ordinarily known as the wet meter, so long as it is duly protected from frost and evaporative heat. Various con- trivances have been suggested and tried for .securing the instrument from these injurious influences. The most general practice is the substitution, in part or in whole, of alcohol for water as the hydraulic seal; but, while this guards against freezing, it gives rise to much inconvenience by reason of its rapid evaporation and want of specific gravity, which oftentimes cause a, sudden obstruction of the flow of gas at the moment when the stoppage is most inconvenient to the consumer. A liquid free from these objections has long been desired, and, after numerous experiments, I had reason to suppose Iliad discovered it in the solution of neutral chloride of calcium. Accord- ingly, in the year 1843, I introduced this liquid into several hundred meters, for the purpose of giving it a fair practical test. It did not freeze at the lowest natural temperature of our climate, and the strong affinity of the salt for water prevented rapid evaporation; while its specific gravity, being greater than that of water, gave full support to the valve-float, and effective- ness to the hydraulic sealing. The results of the first year of trial were entirely satisfactory, and the liquid was then used in all the exposed meters with equally good results. But the expectations raised by two years of trial were dissipated at the end of the third year; by which time the metals of the meter showed such unmistakable evidences of the destructive action of the solution as led to its abandonment. More recently I have been giving trial to another liquid, with encouraging prospect of success. It is the inert substance obtained from fatty bodies, and known by the name of glycerine. It is capable of resisting our low- est natural temperature, maintains its fluidity very pertinaciously, and is considerably heavier than water. Should it manifest no injurious action on the meter metals, or other defects, it will completely meet the wants of the instrument. A more direct method of escaping thesje liquid imperfections has been attempted in the so-called dry meter, working on the pi'inciple of the ordinary bellows, with diaphragms connected by flexible joints. A trial of these, on a large scale, during the years 1847 and 1848, revealed imper- fections which impaired their trustworthiness so greatly as to require their entire disuse. Within a few years sundry improvements have been made in the construction of the dry meter, intended to remove the imperfections be- fore mentioned, which seem to have sufficient merit to justify another trial. This has been in progress for nearly three years, with results, thus far, quite favorable; and if these shall be confirmed by longer and more extensive trial, the annoyances that have so long attended this part of gas machinery may be happily terminated. COAL-OIL. Although the manufacture of gas is rapidly extending in every direction, and the fact is becoming more widely known that in any town containing more than one thousand inhabitants a gas company can with profit be sus- tained, still, at present the number of gas works in operation in this country does not exceed four hundred, and consequently a large demand exists for other means of illumination. Coal-oil from its inexpensivencss, safety, and high photometric value, occupies an important place among the illu- minating agents at present in use, and has given rise to an extensive trade, which cannot fail to be much increased, though at present it is somewhat depressed. 88 ANNUAL OF SCIENTIFIC DISCOVERY. Extensive manufactories of coal-oil are now in operation at New York, Boston, Baltimore, Cincinnati, Philadelphia, Pittsburgh, Brooklyn, and many other places. The production will doubtless continue to augment, as the demand for prime qualities now exceeds the supply. It is to be regretted that much of the oil produced in this country is impure, containing a super- abundance of the heavier hydro-carbons, which, except they are removed, produce smoke and fill the apartment with unpleasant odors. The remedy for these evils will be applied, and re-distillation, or some less wasteful and more efficient process of purification, will be adopted, as competition is excited and the manufacture progresses. Of coal-oil lamps and burners, about 150,000 dozen are estimated to be in use, each lamp consuming about four gallons of oil during the year. The amount of oil burnt averages consequently 7,200,000 gallons a year, or about 20,000 gallons every day. To make 22,750 gallons of burning oil requires 75,000 gallons of crude coal-oil, or a consumption of 00,000 bushels of cannel coal. The erection of crude oil and refining works to make this quantity of oil each day will cost $3,000,000; but the actual outlay for the oil-works at present in operation does not fall short of $8,000,000. The value of chemi- cals used in the purification of coal-oil will amount to over $2,000 per day. The number of barrels used to hold coal-oil will be between 500 and COO, representing the value of $1,000 and the labor of 400 men. The aggregate value of the coal-oil itself will amount to $16,000 per day, or more than $5,000,000 a year. This, too, does not include heavy oil and paratfine, the sale of which is limited and uncertain. The number of workmen employed in the several coal-oil works in this country will reach 2,000; that of the miners engaged in mining cannel, 700 more. Besides these, a large force of men is employed in making lamps, burners, wicks, chemicals, etc. Gas Liyht Journal. THE AMERICAN SCREW CLOCK. Large sums are annually paid in this country for fancy clocks imported from France and Germany, the value of which commonly consists more in their cases and tinsel work than in the excellence of their machineiy and the accuracy of their movements. The cheap clocks of Connecticut manufac- ture, the wheels of which are cut out by dies, are quite as good time-keepers as most of the foreign clocks, and take their place in this country, and to some extent in Europe also, where correct time-keeping at least possible cost is alone desired. In these, and in watches made also on the same principle of multiplying the parts by machinery, so that the pieces may be put toge- ther indiscriminately, the American manufacture has of late years made great progress, lessening the foreign importations, and greatly increasing the use of these valuable instruments. But in ornamental clocks we are still dependent upon European manufacturers. We therefore welcome the introduction of a beautiful ornamental clock, upon an entirely new principle, of great simplicity of design, and so con- structed as to possess the accuracy of movement of a chronometer watch. Its works, however, are fully exposed to view under the glass that incloses them, and a better opportunity is thus afforded of learning the principles upon which this useful machine is constructed than from any other clock in use. The clock to which we refer is a recent invention of Mr. James Tuerlynx, MECHANICS AND USEFUL ARTS. 89 of Xcw York City. Its chief peculiarity consists in its motive power. Upon the circular metallic plate which forms the base of the clock is firmly fixed an upright steel screw, standing from ten to fifteen inches in height. A metallic ball of about two pounds weight is penetrated through its centre by this screw, and when at the upper end tends to run down the spiral inclined plane by revolving around it. By an ingenious arrangement, it is made to roll upon a little wheel attached to the top of the weight, without itself touching the screw; the friction is thus reduced to the least possible amount; and as by raising the weight this little wheel starts back and again catches in the thread of the screw at whatever point the weight is lifted, the only winding up required is simply to raise the weight, and for this a rod is pro- vided, the upper end of which terminates in a ring or knob outside the clock, and the lower end in a circle, which 'takes the base of the weight as the rod is lifted. The revolution of the ball is communicated to the main wheel, which lies horizontally upon the bottom of the plate, by means of two rods that pass through the bull and are fixed to this wheel. A horizontal bar connects their upper ends, and the middle point of this bar is supported and turns upon the top of the screw. On this centre is the wheel, attached to the upper surface of the cross-bar, which regulates the movement of tho hands upon the dial. The main wheel at the base is connected immediately with the escapement and balance-wheel, by which its motion is checked, and let out tick by tick with each swing of the balance. In these clocks the balance is on the compensation principle. The regulation is like that of a watch, and is reached by a wire introduced, when required, through a little hole made in the glass for this purpose. From the perfection of the works, and the holes beijig jeweled, the clock runs at regular rates, and as a time- keeper is probably not surpassed by any other of the same cost. The works arc perfectly protected from dust, and the hands are covered by a glass like that of a watch, or, when inclosed, as in some of the clocks, under the glass cylinder, they may be reached through a hole made opposite to them in the glass, by a long key constructed for this purpose. The important points in this clock are: first, the uniform manner of action of the motive power; second, its direct action upon the main wheel without the intervention of toothed wheels, which in other clocks introduce addi- tional friction and causes of irregularity. The motive power required is thus lessened, and the wear proportionably reduced. It is variously constructed with one to three dials, and to run thirty-six hours, fifty hours, or eight days- For family use, no inconvenience is experienced in the use of those which run only thirty-six hours, as the position of the weight is at all times seen, and whenever at a low point is readily lifted by any member of the family. N. Y. Tribune. RECOVERY OF SILVER FROil SILVER-PLATED UTENSILS. An important problem was that of readily obtaining pure silver from old, wora-out plated utensils of copper, etc. A recent number of the Munitcnr Scientifique publishes valuable information on the subject, by M. Soelzel. The best method consists of treating the plated work by sulphuric acid, in which from five to ten per cent of nitrate of soda has been dissolved. The silver disappears, as if by magic, in this solution, before any of the copper is at all acted upon. 8* 90 ANNUAL OF SCIENTIFIC DISCOVERY. APPLICATION OF POISON TO THE CAPTURE OF WHALES. Professor Christison, of Edinburgh, has recently published an account of some remarkable experiments for the capture of whales by poison. The agency employed was hydrocyanic, or prussic acid, inserted in glass tubes, and in weight about two ounces. After various trials to overcome the diffi- culty of discharging the poison from the tubes, a mode was arranged of attaching one end of a strong copper wire to each side of the harpoon near the blade, the other end of which passed obliquely over the tube, then through an oblique hole in the shaft, and finally to a bight in the rope, where it was firmly secured. When the harpoon struck the whale the tubes were crushed. On one occasion, a fine whale was met with ; the harpoon was skilfully and deeply buried in its bod} 7 ; the leviathan immediately sounded, or dived per- pendicularly downwards, but in a short time the rope relaxed, and the whale rose to the surface quite dead. The crew, however, were so appalled by the terrific effect of the poisoned harpoon that they declined to use any more of them; but Professor Christison is confident, from subsequent experiments, that success will be fully attained in this mode of capture. NEW FIRE ALARUM. An instrument has just been introduced, by Messrs. Taylor and Grimshaw, of London, which promises to be of great value as a fire alarm in ware- houses, docks, vessels, and public establishments generally, as well as in private houses. It consists simply of an air-tight cylinder, with an India- rubber top, which, in proportion as the confined air becomes heated, ex- pands and presses a spring, which, at any given elevation of temperature, will set free a common alarum, or fire a pistol or cannon. It is likeAvise capable of being adapted to furnaces, conservatories, and every place where exact ventilation is requisite, since the spring, instead of sounding an alarum, can be made to act upon an aperture for admitting air. It is port- able and inexpensive, and the principle seems likely to be applied to a number of important commercial uses. A NEW FORM OF BATH. M. Mathieu (de la Drome), a well-known French orator, has lately been turning his attention to the subject of medicinal baths. A bath by immer- sion requires from two to three hectolitres of water, which in the case of mere river or spring water is of no consequence as regards expense. But the case is far different when the water is to be impregnated with medicinal substances, some of which are very costly; or when mineral waters are prescribed, which cannot be had in large quantities without considerable outlay, except at the spring from which they are derived. M. Mathieu (de la Drome) has therefore endeavored to ascertain, both by calculation and experiment, what is the real quantity of water which produces a uscfnl ef- fect on a human body in a common bath, and has found that it cannot be more than three or four litres in the course of an hour. To distribute this quantity both equally and economically on the body was, therefore, the question to be solved; and he has accordingly invented an apparatus, which he calls bain Itydrofere. The patient is seated in a kind of box like that used for fumigation, while a powerful ventilator outside transforms the MECHANICS AND USEFUL ARTS. 91 water which is to be used into a minute aqueous dust or dew, just as we see a high wind do with the water issuing from the jets of a fountain. This dew is driven into the box through an aperture on a level with the knees; and owing to the extreme minuteness of its particles, the latter ascend, and then gradually subside on the body. In a short time these particles coalesce and trickle down the body, until at last the water descends in an unceasing stream. This system has now been tried with great success at the Hopital St. Louis, and is generally attracting the attention of medical men. LIQUID GLUE. As long ago as 18-32, Dumoulin published a notice in the Comptes Rendus of the French Academy with reference to the preparation of a liquid glue. He was led to the discovery of a method of procuring it by considering the long-known fact that Avhen solution of glue is frequently heated and cooled, or kept a long time exposed to heat, it loses its property of gelatinizing by cooling, and remains liquid. Under the impression that this change might be caused by the action of the oxygen of the air, and, if so, would be in- duced more speedily by some vigorous oxidizing agent, Dumoulin tried the effect of dilute nitric acid on glue, and shortly found that by its use the product he desired was easily obtained. His method of preparation was as fol- lows : The best Cologne glue is dissolved, at a gentle heat, in an equal weight of water contained in an enamelled or glazed vessel, and when the solution is complete, nitric acid of thirty-six degrees Beaume is added in proportions, and at intervals, to the amount of one-fifth of the weight of the glue em- ployed. Nitrous vapors are abundantly. given off, and a glue is obtained that is perfectly fluid, and may be kept in open vessels for years without alteration. Already, in 1832, this preparation was sold in Paris as inalter- able liquid glue (colle I i guide et inalterable). A better liquid glue than that just described is made with acetic acid. One pound of good glue is dis- solved, Avith heat, in a mixture composed of one pound of strong vinegar, one-quarter of a pound of alcohol, and a very little alum. According to Cavallius, however, alum destroys the tenacity of glue, and should be avoided. In order to make the glue white in color, a quantity of sulphate of lead is added to the solution. The liquid glues now so extensively sold in this country are made with acetic acid, and those we have tested are very excellent preparations. A glue that is liquid at low temperature is not so adhesive as one which requires gentle warming 'to make it flow. Solu- tions of chloride of barium, bichromate of potash, and some other salts, as well as all the various mineral and vegetable acids, also have the property of holding glue in permanent solution. THE ART OF DENTISTRY. Few persons realize the rapid growth of dentistry as a profession. Forty years ago doctors officiated as tooth-pullers, and if decay seized upon a molar it accomplished its work unimpeded. It is an actual fact that in 1820 there were hardly more than thirty practising dentists in this country. Ten years after that, the invention of artificial teeth had given such an impetus to the profession that the thirty had increased to 200. In 1842 it was esti- mated that there were 1,400; in 1818, 2,000. In 1850, the census reported 2,923 practising dentists ; and at the present time there must be at least 5,000. 92 ANNUAL OF SCIENTIFIC DISCOVERY. American ingenuity long since superseded the artificial teeth which were at first manufactured by the French. In twenty years the number of teeth made here has increased from 250,000 to 5,000,000. For all these grinders we cannot find occupation, and a large portion are exported. The capital employed in this single branch of industry is upwards of $500,000. A single firm in Philadelphia use 700 moulds, producing 9,000 different shapes and styles of teeth, costing upwards of $18,000. Of platina alone 300 ounces a month are used simply for pins to fasten the teeth in their places. This firm manufactures 180,000 finished teeth per month. The value of gold-foil it sells amounts to $109,200 per annum. It is estimated that the 5,000 den- tists in the country use no less than $2,500,000, worth of gold per annum. MEDALS IN ALLOYS OF PLATINUM AND IRIDIUM. M. Pelouze recently presented to the Academy of Sciences at Paris, in the name of M. Jacobi, medals of different sizes struck in alloys of platinum and iridium, fused at the laboratory of the Ecole Normale, by the process of MM. Deville and Debray. The alloys contained respectively twenty, ten, and five per cent of iridium. According to the declaration of M. Jacobi, they were rolled cold and without annealing, with great ease, and presented the characters of the most ductile metals. Under the press they take a polish equal to that of coins; and the alloys rich in iridium showed a hardness rather greater than that of gold of 0'916. This hardness is pro- portioned to the quantity of iridium, as is also the resistance of the alloy to aqua-regia, which attains its maximum when the quantity of iridium reaches twenty per cent. WEAR OF GOLD AND SILVER COINAGE. The Gazette of St. Petersburg gives a curious account of an experiment recently made at the mint of that city for the purpose of ascertaining the comparative loss by ordinary wear of gold and silver coin. It appears, con- trary to the generally received opinion, that gold wears away faster than silver. The means employed were as follows : Twenty pounds of gold half- imperials, and as much of silver copecks, coins of about the same size, were put into two new barrels, mounted like churns, which w r ere kept turning for four hours continuously. It was then found, on weighing the coins, that the gold coins had lost sixty-four grammes, while the silver coins had lost only thirty-four grammes ; but as the number of gold pieces was twenty- eight per cent, less than those of silver, the proportion is greater to that amount in favor of the latter. It must, however, be mentioned that the silver contained more alloy than the gold, the standard of the former being 868-lOOOths of pure metal, and that of the latter 916-lOOOihs. The result of the experiment is, that the pecuniary loss on the wear of gold coin is about thirty times more than on silver. STONE-DIGGING AND WALL-LAYING MACHINE. ~\Ve were recently invited to witness, says the New York Tribune, the trial of a machine for digging stones and building wall. The novelty of a ma- chine for such labor excited a good deal of incredulity as to the possibility of substituting mechanical for manual labor in this hardest of farm work; 4 MECHANICS AND USEFUL ARTS. 93 and it was difficult to believe the statement that it would take rocks of five tons' weig-ht out of the ground without digging around them. But seeing is believing; and we have witnessed the machine in actual operation, taking out boulders weighing from one to five tons, and from one-half to seven-eighths under ground, at the rate of one every three min- utes. The machine is a compact and stout iron windlass, on wheels, drawn by one pair of oxen, while another pair, immediately in front of them, are hitched to a rope which works the windlass through cog-wheels, multiply- ing the power some twenty times. The windlass can also be worked by hand, in which case the power is multiplied twice or three times as much. Two very heavy chains are fastened to and reeled upon the barrel of the windlass; they support a hook in whose jaw is hung a piece of chain, which can easily be lengthened or shortened. This chain is reeved through the shanks of the huge hooks which take hold of the rocks. The rocks are previously fitted for the machine by drilling holes in opposite sides, about three-quarters of an inch deep. The machine is driven over a rock; the man at the windlass which is so high that a rock of five or six tons can be lifted two feet from the ground lowers the great grappling hooks; the man below adjusts their points in the holes in the sides of the rocks, length- ening or shortening the chain holding the hooks as the rock is larger or smaller; the man at the windlass then tightens the slack, while the man below gets upon the machine; then both heave at the windlass. If they do not start the rock, the driver helps them, and if the three cannot, it is given up as liable to break the machine. If they do start it, they tell the driver to go ahead, and he drives on the forward team, winding up the windlass. The rock rises out of the ground, and the team yoked to the machine then draws it wherever it is wanted. It can be laid as the bottom stone of a wall, or, if the bottom stones are laid, the machine can be backed up to the wall, and the rock pulled over by the other pair of oxen, and laid on the wall. This all seems very simple and easy, and it is easier than it seems. The holes drilled in the rocks were so shallow that we were expecting all the while that the hooks would slip, or would break away the rock, when the enormous lifting power required to lift it and tear away the earth which wedged many of them down came to be applied. But they did not, and in some cases the hooks were applied even without drilling holes for them. It is a wonder that, among all the inventive Yankees who have spent so many lifetimes digging out rocks with spades, and levers, and chains, and oxen, nobody should have thought of this before. Mr. S. E. Bolles, of Plymouth, Mass., the inventor of the machine, got his patent for it five years ago; but it is only lately, and through an enterprising farmer, that it has been brought to the notice of the public. The machines appear to be very sol- idly built. Thej' weigh a little over a ton, and cost, aside from the patent right to use them, two hundred and twenty-five dollars. Messrs. Knapp & Co. offer to take out all the rocks weighing between one and five tons, on any oi'dinary piece of ground in the counties for which they hold the patent right, at seventeen dollars per hundred. They say it costs three or four times as much to do it in the old way, and that many pieces of ground, Avhich would not pay for clearing up in the old way, can now be smoothed off at a profit. 94 ANNUAL OF SCIENTIFIC DISCOVERY. IMPROVEMENTS IX AGRICULTURAL IMPLEMENTS. Corn-Cutter and Shocker. J. H. Reble, of Dayton, Ohio, has recently brought into operation a novel agricultural implement, in the shape of a corn-cutter and shocker. The machine is about eight feet wide, and drawn by two horses. It cuts the standing maize by means of vibrating knives like those of a mower, and throws it over backward on to a scoop-shaped platform, where the butts ai'e properly arranged by an assistant, who stands behind the driver, and has a suitable long-handled hook for the purpose. The tops of the stalks lie in a pair of arms, and when enough have accumu- lated say one hundred to one hundred and fifty hills to make a shock, they are compressed by means of a rope and windlass; a binding-string is tied around them, and the shock is first raised upward and carried back- ward by a lever which raises a section of the platform, and then tilted up so as to be discharged on the ground right side up. The machine then drives on and repeats the same operation. It requires two horses to draw the shocker, and three men to work it. An improved Hook for a Whijfle-tree, from which the trace never can get loose, however slack it may be, when in use, while it is also as handy to hitch and unhitch as one of the ordinary kind, is a new and successful contriv- ance. This hook is attached to the whiffle-free by an iron strap, plays loosely up and down, and turns quite round behind the whittle-tree, where alone the trace can be hitched and unhitched. As soon as it slips from that position, the hook fits close to the iron at every other point, whether pulled tight or left slack. Naturally, when the trace is slack, the hook falls and hangs by its own gravity below the whiffle-tree, but it is almost, if not quite, impossible that it should turn round upon the rear side so as to unhook. An Improvement in the construction of a Corn-knife, or Tree-pruning Knife, consists in an iron attachment to the end of the handle, which is made to reach up along the under side of the arm nearly to the elbow, where it is loosely buckled. This gives all the strength and leverage of the forearm to relieve the strain upon the wrist. A new Churn, says the New York Tribune, has appeared, which, we believe, will give greater satisfaction than any of its almost innumerable predeces- sors. Heretofore we have found no substitute for the old hard-working but effective dasher churn; but one has, we think, at last been invented. This new churn will make more and better butter from a given quantity of cream than any other we have ever seen, and in a reasonable time, usually less than half an hour. Nor has it any machinery to adjust or keep in order, and nothing but a plain, smooth barrel, inside and out, to keep clean. A child can fill it, churn it, empty it, wash it, with less strength than it takes to lift a bucket of water. It has no dasher, but is simply a plain barrel, of any required size, hung upon iron pivots in a frame, and made to revolve end over end by a crank, the cream dashing back and forth. One end of the barrel is made movable and convenient to take off, and is fastened on by a thumb-screw, air tight. After the cream is put in and the cover fas- tened down, a small air-pump is attached, and the barrel charged with air, and then revolved. "Without attempting a reason, we will say that this aerifying has a remarkable and beneficial effect upon the cream, and appar- ently improves the quantity and quality of the butter. Improved Horse Shoe. A patent has recently been granted to AY. Coleman, MECHANICS AND USEFUL ARTS. 95 of Philadelphia, for a device for relieving the feet of horses from the con- cussion to which they are liable iu passing over pavements. It consists in combining with the shoe a layer of India-rubber and what is called hoof-plate, the rubber being placed between the shoe and the hoof- plate, and the hoof-plate attached to the foot. By this arrangement, while the rubber is removed from contact with the foot, and is so secured as to be permanent and durable, its elasticity is at the same time made available. New Ploughing Machine. A novel ploughing machine has recently been patented by R. F. Hudson and H. G. Pomeroy, of New York City, which operates as follows : "We may suppose two cart-wheels with gearing upon the inner face of the spokes which drives three shafts hung in an oscillating frame, and lying back at the rear of the axle, by which three furrows, each a foot wide and a foot deep, are not only to be turned over, but thoroughly stirred up and pulverized; the operation being something like Avorming a screw through the soil, in so rapid a manner that it keeps the earth flying around in a circle, and that of the three diggers mixing through each other. ON THE DECAY AND PRESERVATION OF BUILDING MATERIALS. The following is an abstract of a recent lecture before the Royal Institu- tion of Great Britain, on the above subject, by Prof. Austed. He commenced by directing attention to the state of the stone in many of the principal buildings in England and on the Continent, illustrating the extreme irregularity with which various- materials, and even various sam- ples of the same material, resist the action of the weather, and fall into decay. He then described the chief building materials, explaining in each case the cause of decay. Commencing with a general remark, that all stones are rotten and weathered at the top of a quarry, or near an earthy surface, and that the action of the weather on them is in some measure thus indicated, he first alluded to granite. He stated its properties of hard- ness and great durability in ordinary cases, but remarked that when soda replaced potash in the felspar, the crystals of felspar were subject to the action of the weather, and that, from some cause little known, the silica base also occasionally failed. Still, the great practical objection to the use of granite is its cost. Passing next to the sandstones, he defined them, mentioning the chief varieties. He stated that the nature of decay in sand- stones was generally the failure of the cementing medium, which is some- times silicious, but more frequently calcareous, or clayey, or even oxide of iron. He pointed out as the causes of decay, the want of sufficient cohe- sion in the cementing medium, the nature of the cementing medium itself, and the effect of expansion and contraction of water absorbed by the stone. The limestones were next considered, and the principal varieties passed briefly under review. They are all freestones, some are crystalline, others semi-crystalline, but most of them are earthy, or oolitcd and absorbent. They consist of particles of carbonate of lime, whether grains, as in the case of chalk, or accumulated lumps, like oolite or roe-stone, or fragments of shell ; and these particles are cemented together by carbonate of lime. The stones are generally laminated, though the bedding is often extremely obscure. When exposed to the action of the air in towns, they absorb moisture and acid gases very readily, and the result is a gradual destruction 96 ANNUAL OF SCIENTIFIC DISCOVERY. of the surface, and often a rapid removal of the particles beneath the sur- face, especially on the planes of bedding. When stones are not placed in a building as they were in the quarry, the surface peels off in natural films, and is more rapidly acted on than it need be; but not unfrequently, even when well placed, the surface gets hardened by exposure more rapidly than the substance of the stone, and a scaling still takes place. The more ex- posed parts, those subject to drip and constant damp, and the more deli- cately sculptured portions, are among the first to decay; and, owing proba- bly to differences in the mode or rate of deposit of the mud of which the limestone was formed, or some partial change that has since taken place, there is great irregularity in the rate of decay. Magnesian limestones, or dolomites, when quite crystalline, behave like marble; but when, as is usual, only half crystalline, they are very apt to become reduced to powder in parts, and the decay thence proceeds with extreme rapidity. The professor next proceeded to consider the remedies for decay. He alluded to paint as at once unsightly and not permanently beneficial, and included the large class of preservatives that have been suggested, in Avhich any animal or vegetable oil or fatty matter was contained, as equally valueless, either peel- ing off, or rotting in the stone, and leaving it soon exposed to ordinary decay. The mineral bitumens, he stated, had not been much tried, owing to their dark, unsightly color. What is required is some mineral prepara- tion. He then alluded to the water-glass, a soluble silicate of potash, origi- nally described by Dr. Fuchs, and applied to indurate stone by M. Kuhl- mann. He explained the principle of this process as depending on slow decomposition by exposure to the air, and stated that, as meanwhile the influences of the weather continued to act, the method could not be adopted with advantage in the open air in a damp climate, where preservation is chiefly required. The only plan that, as far as he was aware, met the requirements of the case, he stated to be that adopted by Mr. Ransome, according to which the absorbent surface, whether of stone or terra-cotta, was saturated with the diluted solution of soluble silicate of soda, and then treated with a solution of chloride of calcium. By the mutual action of these solutions, a double decomposition is induced, the silicie acid parting with its soda to the chlorine, producing chloride of sodium, or common salt, and combining with the lime to form silicate of lime. The salt being washed away, only the silicate of lime remains. The silicate of lime, thus thrown down, he next explained to be a salt, which was not only itself non- absorbent, and singularly powerful in resisting the action of ordinary at- mospheric influences, but as having the property of adhering readily to the surface of the minute particles of which stone was formed. He illustrated this by the case of mortar and concrete, which owe their adhesive properties to this habit of silicate of lime, which is the mineral formed by the mutual action of the cement on the substances in contact with it. The stone hav- ing its particles thus coated with silicate of lime, and all the absorbent sur- face being thus protected, the result is an immediate and great hardening of the stone, so far within its substance as the solutions have been absorbed, and a complete immunity to that extent from the action of atmospheric influences. The stone does not necessarily become non-absorbent, though it can be made so; but it absorbs much less rapidly than before, and appears to resist decay much in the way that some of the best natural sandstones are known to do. MECHANICS AND USEFUL ARTS. 97 * ZEIODELITE A NEW MINERAL PASTE. . The London Chemical News describes, under the above name, a new kind of paste, discovered by Joseph Simon, which becomes as hard as stone, is unchangeable by the air, and, being proof against the action of acids, may replace lead and other substances for various uses. It is made by mixing together nineteen pounds of sulphur and forty-two pounds of pulverized stoneware and glass. The mixture is exposed to a gentle heat, which melts the sulphur, and then the mass is stirred until it becomes thoroughly homo- geneous, when it is run into suitable moulds and allowed to cool. This pre- paration is proof against acids in general, whatever their degree of concen- tration, and will last an indefinite time. It melts at about 120 Centigrade, and may be reemployed without loss of any of its qualities, whenever it is desirable to change the form of an apparatus, by melting at a gentle heat, and operating as with asphalte. At 110 Centigrade it becomes as hard as stone, and therefore preserves its solidity in boiling water. Slabs of zeiode- lite may be joined by introducing between them some of the paste heated to 200 Centigrade, which will melt the edges of the slabs, and when the whole becomes cold it will present one uniform piece. Chambers lined with zeio- delite in place of lead, the inventor says, will enable manufacturers to pro- duce acids free from nitrate and sulphate of lead. The cost will be only one- fifth the price of lead. The compound is also said to be superior to hydraulic lime for uniting stone and resisting the .action of water. PLASTIC COMPOSITIONS IN LIEU OF MARBLE. A Mr. Brooman, of London, has invented a composition, to be used for building and decorating purposes in lieu of marble, which he calls " simili- marble." A communication in the London Engineer describes the process of manufacture as follows: To manufacture similimarble intended to remain white, take sulphate of potass about fourteen ounces; river water, sixteen quarts; gum arabic, two pounds ; purified cement, twenty pounds ; marble or alabaster powder or dust, twenty pounds ; and treat as follows : First mixture Dissolve over a slow fire, stirring all the time, fourteen ounces of sulphate of potass in sixteen quarts of Avater; after fusion, dissolve two pounds of gum arabic. Second mfxture Stir together twenty pounds of purified cement, twenty pounds of marble or alabaster dust, and five pounds of lime, slacked suffi- ciently to cause it to crumble into powder. Pour into a mortar of marble, porcelain, or other suitable material, a part of the first and a part of the second mixture, and stir with a wooden or bone spatula until the ingredients assume the state of thick paste; then beat with a pestle until the mass becomes elastic, which Avill be ascertained by the composition not adhering to the pestle. To make mouldings or castings, grease the mould, and apply a first layer of about one-third of an inch in thickness of the composition as aforesaid; this first layer is backed by another, formed by boiling, for about three or four hours over a brisk fire, hemp, tow, or other filamentous substances, cut small, in the " first mixture " of gum and sulphate of potass. The product is mixed with the " second mixture" in a mortar, and well beaten with a pestle until the filamentous parts are divided through the mass, and the whole reduced to a paste. Thus a composition of great solidity and im- permeability is produced, lighter than and taking an equal polish to marble, and resisting the action of frost better than marble. 9 98 ANNUAL OF SCIENTIFIC DISCOVERY. FIRE-FROOF COMPOSITION TO RESIST FIRE FOR FIVE HOURS. Dissolve, in cold water, as much pearlash as it is capable of holding in solution, and wash or daub with it all the boards, wainscoting, timber, etc. Then, diluting the same liquid with a little water, add to it such a portion of fine yellow clay as will make the mixture the same consistence as common paint; stir in a small quantity of paper-hanger's flour paste to combine both the other substances. Give three coats of this mixture. When dry, apply the following mixture: Put into a pot equal quantities of finely pulverized iron filings, brickdust, and ashes; pour over them size or glue water; set the whole near a fire, and when warm stir them well together. With this liquid composition, or size, give one coat; and on its getting dry, give it a second coat. It resists fire for five hours, and prevents the wood from ever bursting into flames. It resists the ravages of fire, so as only to be reduced to coals or embers, without spreading the conflagration by additional flames ; by which five clear hours are gained in removing valuable effects to a place of safety, as well as rescuing the lives of all the family from danger. Furniture, chairs, tables, etc., particularly staircases, may be so protected. Twenty pounds of finely sifted yellow clay, a pound and a half of flour for making the paste, and one pound of pearlash, are sufficient to prepare a square rood of deal boards. London Builder. EXCLUSION OF DAMP FROM BRICKWORK. The following methods for obviating this evil have been described at the Royal Institute of Architects: Three quarters of a pound of mottled soap are to be dissolved in one gallon of boiling water, and the hot solution spread steadily with a flat brush over the outer surface of the brickwork, taking care that it does not lather ; this is to be allowed to dry for twenty-four hours, when a solution formed of a quarter of a pound of alum dissolved in two gal- lons of water is to be applied in a similar manner over the coating of soap. The operation should be performed in dry, settled weather. The soap and alum naturally decompose each other, and form an insoluble varnish which the rain is unable to penetrate; and this cause of dampness is thus said to be effectually removed. The other method consists of sulphurized oil as a varnish or paint, and is said to improve the color of brick and stone, as well as preserve them. It is prepared by subjecting eight parts of linseed oil and one part of sulphur to a temperature of 278 D in an iron vessel. It is said to keep out both air and moisture, and prevent deposits of soot and dirt, when applied with a brush to the surface of a building of brick or stone, or even of woodwork. London Builder. ON THE USE OF GRANITE. BY GARDNER WILKINSON. As the question of using granite for building and monumental purposes has been much discussed, I would call attention to a fact, which shows at how early a period the ancient Egyptians had watched the effect of atmos- pheric and other influences on stone, and how wisely they had profited by the lessons taught them by experience. They had learned that earth abounding in nitre, from its attracting moisture, had the effect of decom- posing granite, but that in the dry climate of Upper Egypt the stone remained for ages uninjured when raised above all contact with the ground. MECHANICS AND USEFUL ARTS. 09 When, therefore, there was a possibility of its being exposed to damp, thcy based an obelisk, or other granite monument, on limestone substructions; and these last are found to the present day perfectly preserved, while the granite above them gives signs of decay in proportion to its contact with the earth subsequently accumulated about it. I am speaking of Upper Egypt, visited only four or five times in a year by a shower of rain; for in tho Delta granite remains have been affected in a far greater degree than in the Thebaid. Nitre abounds there, and it is remarkable that the obelisks at Alexandria have suffered least on the sides next the sea. The Egyptians seldom used granite as a building-stone, except for a small sanctuary in some sandstone temple; and in the later times of the Ptolemies one or two temples were built entirely of granite. But in the pure Egyptian period, that stone was chiefly confined to the external and internal casing of Avails, to obelisks, doorways, monolithic shrines, sarcophagi, statues, small columns, and monuments of limited size, and was sometimes employed for roofing a chamber in a tomb. The durability of granite varies according to its qualities. The felspar is the first of its component parts which decomposes, and its greater or less aptitude for decay depends on the nature of the base of which the felspar consists. Egypt produces a great variety of granite, and the primitive ranges in the desert east of the Nile, about thirty-five miles from the Red Sea, supplied the Romans wfth numerous hitherto unknown kinds, as well as with porphyry, which they quarried so extensively in that district; but the granite of the ancient Egyptians came from the quarries of Syene, in the valley of the Nile, and from these they obtained what was used for their monuments. It is from this locality that the name of " Syenite" has been applied to a certain kind of granite; it is, however, far from being all of the same nature, and a small portion of the stone found there is really what we now call " Syenite." Already, at the early period of the third and fourth dynasties, between twelve and thirteen centuries before the Christian era, the Egyptians exten- sively employed granite for various purposes. They had learnt to cut it with such skill that the joints of the blocks were fitted with the utmost precision. Deep grooves were formed in the hard stone with evident facility; and it must have been known to them for a long period before the erection of the oldest monuments that remain, the pyramids of Memphis, where granite was introduced in a manner which could only result from long experience. Again, in the time of the first Osirtasen, about 20-50 B. C., granite obelisks were erected at Heliopolis and in the Fyodm, and other granite monuments were raised in the same reign at Thebes, from which we find, that even then the Egyptians had learnt how the damp earth acted on granite when buried beneath it; and this interesting question subsequently suggests itself: How long before that time must the stone have been used to enable them to obtain from experience that important hint which led them to place granite on limestone substructions ? WHAT SHOULD MECHANICAL WORKMEN BE TAUGHT? The following extracts from an address on the above subject, recently delivered at the South Kensington Museum, London, by J. Scott Russelk, F. R. S., contain some views on the education of mechanical workmen which are both novel and interesting. 100 ANNUAL OF SCIENTIFIC DISCOVERT. Students in schools were now taught geometry; they were taught the sixteenth, seventeenth, eighteenth, and nineteenth propositions of Euclid; but that description of knowledge was not of the slightest use to his work- men, or to anybody else. They were also taught mechanics and the law of the lever. That was right; but, then, mechanics and the law of the lever were not ordinarily taught in books in such a way as to be of practical use to the British workman. We did not go far enough. But the pupil teach- ers whom he addressed were not to blame. The persons to blame were their teachers. Two years was, perhaps, all the time that could be devoted to education, and six months were often devoted to as many books of Euclid, which were wasted for all practical purposes, unless, indeed, the student intended to become a professor. He would advise them to skip over the beginning, and devote the least possible time to Euclid; in fact, he would advise them to do a very heterodox thing to cut off all the propositions but the useful ones. They might naturally exclaim, " Then how little will be left." Very little, he admitted; but plane trigonometry would be left. Suppose, for instance, a man had but six months in which to learn. Six weeks might, in that case, be given to Euclid, and then trigonometry might be commenced, solid geometry might next follow, and that constituted the whole education of the workman. But that was precisely what he did not get in the present day. He would also teach, in the six months, conic sec- tions, and afterwards the nature of curves, within the first, second, third, and fourth degrees. AVhat he had said about geometry was true as to mathematics. Thirteen and a half yards at three and a half cents was not what was wanted. Of far more importance to the working-man was the comprehension of the laws and relations of numbers, so as to enable him to think in figures about the immediate business before him. The first and most important doc- trine to remember in mathematics was, that shape is not size, or size shape. This might appear to be an axiom, and he thought it was as good as any in Euclid. The doctrine of similar triangles was a fundamental principle enti- tled to the dignity of an axiom; and it was that, without regard to shape and size, any number of triangles might be made all of the same shape, and not of the same size. Mr. Russell having illustrated this principle by draw- ings on the board, continued to say that, with respect to solid geometry, the two great duties in a workman's life were conversion of materials and adap- tation to strength. A mason who used up a wrong stone, or a carpenter who selected a wrong plank or piece of timber, showed that he was ignorant of one of the most useful portions of his art or calling. Now, nothing would teach conversion of materials like solid geometry; it was, in fact, the daily business of the workman. It had been said that every block of marble cut from the quarry contained a beautiful statue, but the art was how to get it out of it. This was very true; but what workmen wanted to know was every shape, and how to get out another shape. The workman who took from a heap a block of stone or piece of timber that cost his master fifty shillings, when a piece could be got answering quite as well which cost twen- ty-five shillings, inflicted a loss upon his employer perhaps equal to a week's wages. Hence the necessity of acquiring a knowledge of solid geometry. But if there were beauty in the quantity of numbers, and in regular geomet- rical figures, there was infinitely more beauty in curves. It was the duty of many mechanics, especially of those engaged in ship-building, to make curved lines. To him it had always been an interesting subject to learn how MECHANICS AND USEFUL ARTS. 101 curves grew. He was aware that he might be told that the higher curve, were never taught; but his answer was, that they might easily be taught, and that they were very easy of comprehension. In order to effect this, somebody who understood the subject would have to be prevailed upon, not to write a book, but to put down in the shortest and plainest language what he knew of curves. This would be a treatise which the workman could understand. The lecturer then explained, with the aid of the board, the various mathematical figures known as conic sections, parabola, ellipses hyperbola, and the movement of the comets. These, he contended, might be learned so as to make the workman master of the principle within six months. He also thought that there ought to be a large quantity of appa- ratus a sort of inventory of education of every conceivable shape and object. In addition to these models, he would have the school-room hung round, not with pictures of animals, but with solid bodies, which could be explained and drawn. He would, in fact, impart any kind of practical rather than book knowledge. If drawings merely were used instead of models, he did not think the student could imbibe so correct a notion of the object to be produced or delineated. There was a mode of studying forms called la theorie d<- d&vdappement, but the plain English meant nothing more than making flat surfaces into round and angular forms, as models now made from sheets of paper, which was a most valuable mode of studying forms. Machinery could now be obtained to do all the unintellectual drudgery of mechan- ism. He was not opposed to machinery, and had no apprehension that it would supersede skilled intellectual handicraft. He would employ machinery to do all the drudgery that degraded the workman into a beast of burden. He would give him higher views of mathematics; he would show him that he was an intellectual, thinking being, with a soul for high and immortal things. IMPROVED NAILS. A French mechanician states that nails formed with two sloping edges may be driven into thin wood without risk of splitting it, provided they are made to cut the wood across the grain. He recommends manufacturers to make nails of this kind in order to save carpenters the trouble and loss of time involved in using a gimlet or brad-awl. A GREAT MACHINE FOR A SIMPLE PURPOSE, TURNING BAGS BY STEAM. "We have recently examined a machine more complicated than a stocking loom for the simple purpose of turning cloth bags (after they have been sewed or woven) the right side out! "Can it be," we asked the inventor, " that there is a demand for machinery for performing so trifling an opera- tion as this?" "O, yes," he said; "it takes as much time to turn a bag as it does to make it, at the present day. In our neighborhood there are two large cotton manufactories devoted exclusively to making cloth for bags. In the country there are probably three hundred bag manufacturers, employing from two to fifty turners each, and one of these machines will do the work of thirty hands. One of the large manufacturers in this city told me that the machine, besides saving in wages, would enable him to effect considerable economy in his rent, 9* 102 ANNUAL OF SCIENTIFIC DISCOVERY. from the small room occupied by the machine in comparison with all the hands he now employs for turning." The machine works in the most accm-ate, rapid, and beautiful manner, but it would be difficult to give any clear idea of its ingenious mechanism without diagrams. Scientific American. IMPROVEMENT IN GAS-BURNERS. A patent has been recently taken out in England for a gas-burner of the following simple construction, designed to prevent the flickering of the light. It consists of a tubular cap of thin cast-iron or other metal, having a wide internal diameter, so as to fit by its open lower end upon or over an existing burner. The top of the burner is in the form of a solid convex end, through which a vertical slit is made to form the actual burner aperture for the gas, and produces a thin, broad, flat flame. When such a tubular cap is fitted upon or over an ordinary burner, the gas is received into the reservoir of the tubular cap, and it thence passes slowly off through the burner slit. The reservoir intervening between the common burner beneath and the burner slit in the top of the cap above, acts as a pressure-regulator, to prevent flick- ering and inordinate forcing of the gas, whilst the broad flame insures the production of a brilliant light. Scientific American. NATURAL PHILOSOPHY. ON PHYSICS AS A BRANCH OF THE SCIENCE OF MOTION. THE following are the chief points of a paper on the above subject, pre- sented to the British Association, I860, by J. S. Gleniiie: The object of the author was not to enter into the full subject, but, by sub- mitting it to discussion, to gain the advantage of criticism. He conceives atoms as mutually determining centres of pressure, that is, more definitely, as centres of lines, the intensity and direction of which are determined by the intensity and direction of the lines from surrounding atoms. Thus, atoms are neither conceived as particles of matter, acted on by extraneous forces of attraction and repulsion, nor as vague centres offeree; and that pressure generally is conceived as measured by M. 0. Motion is not conceived as "a quality of matter, of which no further account can be given," but as the effect in any place of a difference of the polar pressures on a body in that plane. The principle to which the author most constantly has to refer is, that "the motion of a body is in the direction of least resistance; or, motion is the effect of, and proportional to, the difference of polar pressures. From thence, by a train of mixed metaphysical and mathematical conceptions, to deduce that gravity, the law of universal attraction, is the mechanical con- sequence of difference in the masses of a system, mutually connected by their lines of pressures and repelling; and that thus the law of the inverse squares is rather a mathematical than a physical law. ON THE NECESSITY FOR INCESSANT RECORDING, AND FOR SI- MULTANEOUS OBSERVATIONS IN DIFFERENT LOCALITIES, TO INVESTIGATE ATMOSPHERIC ELECTRICITY. The following is an abstract of a paper on the above subject presented to the British Association, Aberdeen, by Professor W. Thompson : The necessity for incessantly recording the electric condition of the atmos- phere was illustrated by reference to observations recently made by the author in the island of Arran, by which it appeared that even under a cloud- less sky, without any sensible wind, the negative electrification of the surface of the earth, always found during severe weather, is constantly varying in degree. He had found it impossible, at any time, to leave the electrometer without losing remarkable features of the phenomenon. Beccaria, Profes- sor of Natural Philosophy in the University of Turin a century ago, used to 104 ANNUAL OF SCIENTIFIC DISCOVERY. retire to Garzcgna when his vacation commenced, and to make incessant observations on atmospheric electricity, night and day, sleeping; in the room with his electrometer, in a lofty position, from which he could watch the sky all round, limited by the Alpine range on one side, and the great plain of Piedmont on the other. Unless relays of observers can be got to follow his example, and to take advantage of the more accurate instruments supplied by advanced electric science, a self-recording apparatus must be applied to provide the data required for obtaining knowledge in this most interesting field of nature. The author pointed out certain simple and easily-executed modifications of working electrometers, which were on the table before him, to render them self-recording. He also explained a new collecting appa- ratus for atmospheric electricity, consisting of an insulated vessel of water, discharging its contents in a fine stream from a pointed tube. This stream carries away electricity as long as any exists on its surface, where it breaks into drops. The immediate object of this arrangement is to maintain the whole insulated conductor, including the portion of the electrometer con- nected with it and the connecting wire, in the condition of no absolute charge ; that is to say, with as much positive electricity on one side of a neutral line as of negative on the other. Hence the position of the discharg- ing nozzle must be such that the point where the stream breaks into drops is in what would be the neutral line of the conductor, if first perfectly dis- charged under temporary cover, and then exposed in its permanent open position, in which it will become inductively electrified by the aerial electro- motive force. If the insulation is maintained in perfection, the dropping will not be called on for any electrical effect, and sudden or slow atmospheric changes will all instantaneously and perfectly induce their corresponding variations in the conductor, and give their appropriate indications to the electrometer. The necessary imperfection of the actual insulation, which tends to bring the neutral line downwards or inwards, or the contrary effects of aerial convection, which, when the insulation is good, generally preponder- ate, and which, in some conditions of the atmosphere, especially during heavy wind and rain, are often very large, are corrected by the tendency of the dropping to maintain the neutral line in the one definite position. The objects to be attained by simultaneous observations in different localities alluded to were: 1. To fix the constant for any observatory, by which its observations are reduced to absolute measure of electro-motive force per foot of air. 2. To investigate the distribution of electricity in the air itself whether on visible clouds or in clear air by a species of electrical trigo- nometry, of which the general principles were slightly indicated. A port- able electrometer, adapted for balloon and mountain observations, with a burning match, regulated by a spring so as to give a cone of fire in the open air, in a definite position with reference to the instrument, was exhibited. It is easily carried, with or without the aid of a shoulder-strap, and can be used by the observer standing up, and simply holding the entire apparatus in his hands, without a stand or rest of any kind. Its indications distinguish positive from negative, and- are reducible to absolute measure on the spot. The author gave the result of a determination which he had made, with the assistance of Mr. Joule, on the Links, a piece of level ground near the sea, beside the city of Aberdeen, 8 A.M. on the preceding day (September 14), under a cloudless sky, and with a light northwest wind blowing, with the insulating stand of the collecting part of the apparatus buried in the ground, and the electrometer removed to a distance of five or six yards, and NATURAL PHILOSOPHT. 105 connected by a fine wire with the collecting conductor. The height of the match was three feet above the ground, and the observer at the electrometer lay on the ground to render the electrical influence of his own body on the match insensible. The result showed a difference of potentials between the earth (negative) and the air (positive) at the match equal to that of one hundred and fifteen elements of Daniel's batteiy, and, therefore, at that time and place, the aerial electro-motive force per foot amounted to that of thirty- eight Daniel's cells. ON THE THEORY AND CONSTRUCTION OF LIGHTNING-RODS. The theory of a thunder-cloud and a conductor ought to be better under- stood in this country than it is, seeing that it lies almost in a nutshell. Lightning obeys one unvarying law, it uniformly follows the best continuous conductor; but no conductor can be considered a good one unless it is con- tinuous. Numerous evidences of this have been afforded by broken or other- wise defective rods. A flash takes the rod and follows it to where the break exists, then finds its next best conductor within the building, immediately opposite the spot where it discovered the break, crashes through the wall, perhaps where the family are sitting, and deals death around it, finding its way into the earth by tortuous channels, the stove-pipe, the gas-pipe, or, in their absence, by shattering the wood-work and plastering. Defective rods of any kind are mere traps to bring lightning into a house, instead of keep- ing it out. They are the most dangerous fixture a man can have about him ; and though numerous crudely written paragraphs are constantly afloat of houses being damaged, though provided with rods, yet it may be assumed as absolutely certain that in every such instance the rod has been miserably out of order, or put up meanly and cheaply by direction of a penurious owner, or by an ignorant and incompetent peddler. The principle of protec- tion developed by Franklin remains sound ; and all that is needed to secure perfect immunity from danger is a strict adherence to what we know it demands as the condition of safety. When the usual term for thunder-storms is coming on, every careful householder should have his lightning rods ex- amined, and, if found defective, put in perfect order. The joints should be seen to be close and tight, for continuity is indispensable to safety. If the winter's storm has bent that part which projects above the roof, it should be taken down and straightened. See, also, that the lower section which goes into the ground has not rusted off, as is often the case. And this thorough examination should be made every year. Thunder-clouds are charged with different degrees of intensity, some heavily, some lightly. Some sweep over the earth at a greater altitude than others. Those which hang low discharge their contents, whether of water or electricity, with the greatest energy. All our thunder-storms, with few exceptions, come up from the northwest. Hence the conductors should be erected at those points of the building with which the cloud will first come in contact. This is necessary, because every thunder-cloud is sur- rounded by an electric atmosphere, which precedes the cloud itself. This may be easily verified by placing the knuckle to the conductor as the cloud ap- proaches. Sparks will frequently be drawn from it while the thunder yet rolls in the distance, showing that the electrical haze has already enveloped the building, and that the rod is silently conducting the fluid into the earth. The rod is already performing its functions with the mere electrical atmos- 106 ANNUAL OF SCIENTIFIC DISCOVERY. phorc, just as it would seek to do if assailed by an explosion from the cloud. But thousands of rods have been put up by the peddlers in direct violation of this rule, even when the prominent points of the building were in tlic proper quarter. The gable-ends of barns most remote from the approaching cloud are selected by them as frequently as the proper end. Persons of the highest pretensions in their business of making conductors are constantly committing this grievous error. It cannot be too speedily and generally corrected. Some five years ago a young woman was picking cherries in a tree which stood near her father's house, in Warren County, New Jersey. A cloud was seen to be approaching, though at a great distance. But it was surrounded and preceded by a highly excited electrical atmosphere. There was no rain, as the cloud was a great way off. Yet persons in the neighbor- hood saw a flash traverse the air in an almost horizontal line, and shatter the tree in which the girl was seated, and she was killed. This was an unusual occurrence; and yet a similar discharge has been seen to leave a cloud and traverse a great distance, until it reached a stream of rarefied air, sent up from a barn but recently filled with new hay. It followed this stream as a choice conductor, struck, and destroyed the barn. This presence of an electrical atmosphere has sometimes exhibited the most remarkable phenomena. The great lightning storm of June, 1848, was especially productive of them. Mr. Cooper's rolling-mill at Trenton, N. J., seemed to be charged in every part with electricity. Though that storm extended over a surface of seven hundred miles, yet no place witnessed a more singular display of its mighty energies than Trenton. The lightning struck the earth there repeatedly. A workman at the rolling-mill attempted to lower the iron-damper, which was connected with iron chains, but he no sooner laid his hand on the latter than he received a shock which prostrated him. A second workman repeated the attempt, and was in turn knocked down, while the third also received a severe shock. A fireman attempted to stir the melted iron in the furnace, but the instant his iron-stirrer touched the fluid metal he received a violent shock. Other similar facts occurred, show- ing that the whole atmosphere was charged with electricity to an extraor- dinary extent, and that chains, bars, furnaces, and even the melted metal, were silently acting as conductors between the cloud and the earth, giving out neither shock nor spark unless touched by the unconscious workman. The masses of metal which surrounded the three hundred hands employed in the mill were so many potent protectors. But the same precautions should be used to guard against the electrical atmosphere which invariably precedes and surrounds a thunder-cloud, as against the cloud itself. The true position in which the rods should be affixed having been ascer- tained as mentioned above, the next important question is as to the quantity of iron to be used. A wire one-quarter inch thick will effectually protect any building, providing there be a point of stiff metal set up on every prominent part, with as many outlets into the ground as there are points in the air, the whole being connected by cross wires extending over the building. Galvan- ized wire is preferable to all others, as it is not liable to oxidation. The greater the quantity of iron, and the more numerous the outlets, the greater the safety. This is in accordance with Franklin's directions, except that the quantity of iron is increased. A large building should have some hundreds of feet of rod, and any building whatever should have not less than two points and two outlets. There is a good reason for this apparent profusion of iron. Explosions of electricity vary in intensity, some being very feeble, NATURAL PHILOSOPHY-. 107 while other? are of awful power. No certain calculation can be made as to whether the coming shock Avill be light or heavy; hence it is prudent to guard against the latter, as in doing so we effectually disarm the former. A light shock will be carried off by a single rod without injury; but the dis- charging power of such a rod being uniform with its receiving power, because of its single outlet, an explosion on its point may occur, charged with so pro- digious a volume of electricity that the capacity of the rod is not great enough to carry it off. Herein lies the great danger of an insufficient conductor. The discharging power being fixed and limited, any excess of electricity will leave the conductor, fly off into the house in search of another, whether it be the stove-pipe or the human body, and do its deadly work. Innumerable cases where such results have followed an excessive discharge on a conduc- tor having a single outlet to the earth are on record. Accounts are often published of injury to buildings, though protected by conductors ; but careful examination into the facts of the case has invariably shown that, though the conductor was free from defect, its capacity was too small to break up and carry off a heavy shock. It follows, then, that the discharging power of a conductor must be equal to its receiving power; that a building should be armed with points on all its prominent projections, because no cal- culations can be made on whicrT prominence the shock may fall; that these receiving points should have numerous discharging points descending to moisture in the earth, and that the whole should be connected by wires in several directions across the roof, so that whichever point may happen to receive the shock will be aided by the entire network of metal in instantly mitigating its intensity by distributing it over a large surface, and passing it off by numerous outlets. The fluid concentrated in the shock had been pre- viously distributed over the surface of an immense body of clouds. How unreasonable it is to expect a single discharging point to pass off the volume of electricity accumulated in so great a body of vapor. It is for these reasons that the cheap conductors are found so often mere traps, bringing the dan- gerous element into a building, instead of leading it away. It is a mistake, as well as a useless expense, to put up glass insulators to prevent the lightning from leaving the rod and passing into the house. No flash will quit a properly-constructed rod, because lightning never avoids a good conducting medium to follow a bad one. Hence, the rod being con- tinuous and the staple not so, iron staples are entirely safe. An explosion will shatter glass ones into fragments, and the sleet and ice of winter will as certainly destro3 r them. As few thunder-clouds pass over without discharg- ing their watery contents, the glass insulators become wet, and while in that condition are as good conductors as the iron staples. An immense amount of humbug has been propagated among the people by ignorant peddlers, engaged in selling rods, on the necessity of glass Insulators. They have introduced and sold them as indispensable to protection, either through entire ignorance of their worthlessness, or to enhance the profit on their wares. So also, with respect to gold or platinum points, costing several dollars each. These serve no other purpose but to prevent oxidation. But the point of a lightning-rod rarely or never oxidates. Its exposure to the air causes it to dry rapidly. If galvanized iron be used, as recommended for the wire, it will stand for centuries uninjured. The great object is to make every prominent part of the building bristle with points, and to supply them with an abundance of outlets to the earth, giving to the whole rod a dis- charging power proportioned to, or even greater than, its receiving power. New York Tribune. 108 ANNUAL OF SCIENTIFIC DISCOVERY. WAY'S NEW ELECTRIC LIGHT. The principle of a new device for obtaining an electric light, originated by Professor Way, of London, is the application of the current of a voltaic bat- tery to a moving column of mercury. The mercury is contained in a crystal globe of the size of an orange, whence it flows through a very minute orifice in the form of a thin metallic thread, not larger than a very small needle, to a little cup below. From this cup it falls into a basin, to be again restored to the globe or reservoir above. During its passage from the globe to the cup it comes into contact with the wires of the battery, and a vivid light is pro- duced, ceasing whenever the contact is interrupted. The continuance of the light is regulated by a piece of clock-work machinery, carrying a revolving disc, the face of which is covered with numerous holes, with pins to fit in as may be required. In front of the disc are two small cylinders, with pistons and arms attached. As the disc revolves, the pins in its face lift the pistons in the cylinders and cut off the connection between the battery and the lighting apparatus, producing flashes of light of any duration that may be required. A nocturnal excursion was lately made from the Isle of Wight, to test the efficiency of this light. The simple machinery was hoisted to the mast- head, and there soon shone out upon the surrounding land and water a light almost unnaturally brilliant. Osborne, the country-seat of the Queen, with its groves, and gardens, and walks, was rendered in every part distinctly visible. When at some distance out, it was found necessary to send a boat to the shore, and a little yawl pursued its way along a track of light, which made it easily seen from both the ship and the land. The success of the experiment was complete, and the large numbers who witnessed it pro- nounced Professor Way's invention far superior to any electric light hitherto introduced. GASSIOT'S IMPROVEMENT IN TEE ELECTRIC LIGHT. It has long been known that, under certain circumstances, the electric discharge from a voltaic battery can be made to traverse short distances across air in the form of an intensely luminous, but, at the same time, intensely hot spark. If this discharge is made to pass through a glass tube, by means of platinum wires sealed into the extremities, the air having previously been exhausted from it by means of an air-pump, the discharge assumes an entirely different aspect. Instead of appearing in the form of disconnected sparks, the electric fluid traverses it like a continuous stream of nebulous light, filling the tube with a beautiful phosphorescent glow, whilst the heat almost disappears ; on this account it was until very recently considered that electricity passed through a vacuum. Recent researches have, however, shown that a vacuum really is a non-conductor to the passage of the electric fluid, and that the phenomenon of conduction apparent in the " vacuum tube" was really due to the great conducting power possessed by a highly rarefied gas. As soon as this was known, it became a matter of great interest to electricians to ascertain the various effects which would be produced by having the tube filled with various sorts of gases, and also what difference was caused by alterations in the size and shape of the vacuum tubes employed. The subject was especially investigated by Mr. Gassiot, the well-known NATURAL PHILOSOPHY. 109 English ph} T sicist, and the result of his researches has been the discovery of a ready and simple means of applying the electric discharge from the induc- tion coil to the purposes of illumination. A carbonic acid vacuum tube (that is, a tube filled with carbonic acid, which is then exhausted from it by means of an air-pump, until there is only the most infinitesimal trace of gas remaining), having an internal diameter of about one-sixteenth of an inch, is wound in the form of a flattened spiral; to the ends of the tube are attached two wider tubes into which platinum wires are sealed; they are inclosed in a wooden case, so as to permit only the spiral to be exposed. When the discharge from a Ruhmkorff's induction apparatus is passed through the vacuum tube, the spiral becomes intensely luminous, exhibiting a brilliant white light. M. Gassiot, who exhibited the instrument in action at a recent meeting of the Royal Society, caused the discharge to pass through two miles of copper wire, showing that it would be applicable to illumination at a distance. The results were brilliant in the extreme; and it was confidently predicted that the new device would shortly constitute one of the most useful and popular fprms of the electric light. ON THE USE OF THE ELECTRIC LIGHT FOR LIGHTHOUSE ILLUMI- NATION. The following is an abstract of a lecture on the above subject by Professor Faraday, recently delivered before the Royal Institution, London : The use of light to guide the mariner as he approaches land, or passes through intricate channels, has, wilh the advance of society and its ever in- creasing interests, caused such a necessity for means more and more perfect, as to tax to the utmost the powers both of the philosopher and the practical man, in the development of the principles concerned, and their efficient application. Formerly the means were simple enough; and if the light of a lantern or torch was not sufficient to point out a position, a fire had to be made in its place. As the system became developed, it soon appeared that power could be obtained, not merely by increasing the light, but by directing the issuing rays ; and this was, in many cases, a more powerful and useful means than enlarging the combustion, leading to the diminution of the volume of the former, with, at the same time, an increase in its intensity. Direction was obtained, either by the use of lenses dependent altogether upon refraction, or of reflectors dependent upon metallic reflection ; and some an- cient specimens of both were shown. In modem times the principle of total reflection has also been employed, which involves the use of glass, and depends both upon refraction and reflection. In all these appliances nmch light is lost. If metal be used for reflection, a certain proportion is ab- sorbed by the face of the metal; if glass be used for refraction, light is lost at ah 1 the surfaces where the ray passes between the air and the glass; and also in some degree by absorption in the body of the glass itself. There is, of course, no power of actually increasing the whole amount of light, by any optical arrangement associated with it. The light which issues forth into space must have a certain amount of divergence. The divergence in the vertical direction must be enough to cover the sea from the horizon to within a certain moderate distance from the shore, so that all ships within that distance may have a view of their lumi- nous guide. If it have less, it may escape observation where it ought to be seen; if it have more, light is thrown away which ought to be directed within 10 110 ANNUAL OF SCIENTIFIC DISCOVERY. the tiscful decree of divergence; or if the horizontal divergence be considcrcrl, it may be necessary so to construct the optical apparatus, that the light within an angle of sixty or forty-five degrees shall be compressed into a beam diverging only fifteen degrees, that it may give in the distance a bright flash having a certain duration instead of a continuous light; or into one diverging only five or six degrees, which, though of far shorter duration, has greatly increased intensity and penetrating power in hazy weather. The amount of divergence depends in a large degree upon the bulk of the source of light, and cannot be made less than a certain amount, with a flame of a given size. If the flame of an argand lamp, seven-eighths of an inch wide and one and a half inches high, be placed in the focus of an ordinary Trinity House parabolic reflector, it will supply a beam having about fifteen degrees divergence. If we wish to increase the effect of brightness, we cannot prop- erly do it by enlarging the lamp flame; for though lamps are made for the dioptric arrangement of Fresnel, which have as many as four wicks, flames three and a half inches wide, and burn like intense furnaces, yet if one be put into the lamp place of the reflector referred to, its effect would chiefly be to give a beam of wider divergence; and if, to correct this, the reflector were made with a greater focal distance, then it must be altogether of a much larger size. The same general result occurs with the dioptric apparatus; and here, where the four-wicked lamps are used, they are placed at times nearly forty inches distant from the lens, occasioning the necessity of a very large, though very fine, glass apparatus. On the other hand, if the light could be compressed, the necessity for such large apparatus would cease, and it might be reduced from the size of a room to the size of a hat; and here it is that we seek in the electric spark, and such like concentrated sources of light, for aid in illumination. It is very true that by adding lamp to lamp, each with its reflector upon one face or direc- 1ion, power can be gained; and in some of the revolving lights ten lamps and reflectors unite to give the required flash. But then not more than three of these faces can be placed in the whole circle; and if a fixed light be required in all directions round the lighthouse, nothing better has been yet estab- lished than the four-wicked Fresnel lamp in the centre of its dioptric and catadioptric apparatus. Now the electric light can be raised up easily to an equality with the oil lamp, and if then substituted for the latter, will give all the effect of the latter; or, by expenditure of money, it can be raised to a five or tenfold power, or more, and will then give five or ten-fold effect. This can be done not merely Avithout increase of the volume of the light, but whilst the light shall have a volume scai-cely the two-thousandth, part of that of the oil flame, Hence the extraordinary assistance we may expect to obtain of diminishing the size of the optical apparatus and perfecting that part of it. Many compressed intense lights have been submitted to the Trinity House; and that corporation has shown its great desire to advance all such objects, and improve the lighting of the coast, by spending, upon various occasions, much money and much time for this end. It is manifest that the use of a lighthouse must be never-failing, its service ever sure; and that the latter cannot be interfered with by the introduction of any plan, or proposition, or apparatus, which has not been developed to the fullest possible extent, as TO the amount of light produced, the expense of such light, the wear and tear of the apparatus employed, the steadiness of the light for sixteen hours, irs liability to extinction, the amount of necessary night care, the number of NATURAL PHILOSOPHY. Ill attendants, the nature of probable accidents, its fitness for secluded places, and other contingent circumstances, which can as well be ascertained out of a lighthouse as in it. The electric spark which has been placed in the South Foreland High Light, by Professor Holmes, to do duty for the six winter months, had to go through all this preparatory education before it could be allowed this practical trial. It is not obtained from frictional electricity, or from voltaic electricity, but from magnetic action. The first spark and even magnetic electricity as a whole was obtained twenty-eight years ago. (Faraday, Philosophical Transactions, 1832, p. 32.) If an iron core be sur- rounded by wire, and then moved in the right direction near the poles of a magnet, a current of electricity passes, or tends to pass, through it. Many powerful magnets are therefore arranged on a wheel, that they may be asso- ciated very near to another wheel, on which are fixed many helices with their cores like that described. Again : A third wheel consists of magnets ar- ranged like the first; next to this is another wheel of the helices, and next to this again a fifth wheel carrying magnets. All the magnet wheels are fixed to one axle, and all the helix wheels are held immovable in their place. The wires of the helices are conjoined and connected with a commutator, which, as the magnet wheels are moved round, gathers the various electric currents produced in the helices, and sends them up through two insulated wires in one common stream of electricity into the lighthouse lantern. So it will be seen that nothing more is required to produce the electricity than to revolve the magnet Avheels. There are two magneto-electric machines at the South Foreland, each being put in motion by a two-horse power steam-engine; and, excepting wear and tear, the whole consumption of material to produce the light is the coke and water required to raise steam for the engines and car- bon points for the lamp in the lantern. The lamp is a delicate arrangement of machinery, holding the two carbons between which the electric light exists, and regulating their adjustment; so that whilst they gradually con- sume away, the place of the light shall not be altered. The electric wires end in the two bars of a small railway, and upon these the lamp stands. When the carbons of a lamp are nearly gone, that lamp is lifted off and another instantly pushed into its place. The machines and lamp have done their duty during the past six months in a real and practical manner. The light has never gone out through any deficiency or cause in the engine and machine house, and when it has become extinguished in the lantern, a single touch of the keeper's hand has set it shining as bright as ever. The light shone up and down the Channel, and across into France, with a power far surpassing that of any other fixed light within sight or anywhere existent. To show the necessity for an intense light in lighthouse illumination, Dr, Faraday reminded his audience of the dark shadow thrown by the steam is- suing from a railway locomotive on a sunshiny day; and, having cast a con- centrated light from the electric lamp upon a screen, he showed how instan- taneously it was darkened by an artificial cloud made of high pressure steam, and which might be taken as an illustration of the effect of the sea fogs and mists so common near the coast. ELECTRIC LIGHT TELEGRAPH. Mr. Caselli purposes to employ the electric light for telegraphic purposes during war, or in situations that do not admit of the usual communication by wire. Signals like those of Morse would be represented by two lengths 112 ANNUAL OF SCIENTIFIC DISCOVERY. of light, one long and the other short, and by celipses of three lengths or durations, lie proposes to obtain the light either 1'rom a Biinscn buttery of fifty elements, or from a magneto-electrical machine, and gives a preference to the latter, as the charcoal points are equally consumed, which is of conse- quence when a lens is employed to concentrate the rays. VELOCITY OF ELECTRICITY. M. M. Guillemin and Burnouf, of France, have recently instituted an ex- tensive series of experiments on the transmission of electricity by telegraphic wires, with a view of discovering some law which governs its transmission. They conclude from their researches that the electric fluid is not propagated like the waves or undulations of light, and that it has not a constant and uniform velocity. They find it necessary to fall back upon the idea of Ohm, expressed in 1827, that electricity is propagated through wires, in virtue of the same kind of laws which govern the propagation of heat in a metallic bar. To determine experimentally which of these two opinions ought to prevail, that is, whether electricity is propagated with a constant and uni- form velocity, or whether it is transmitted like heat, the authors disposed an apparatus, showing the intensity of the electric current in a certain point of a conducting wire, at different instants of its propagation. The first or the second opinion would then be justified, according as the current acquired suddenly in this point its definite intensity, or arrived at this intensity grad- ually. The authors found that the current at the point in question began with a very feeble intensity (the galvanometer marking 50'), which aug- mented gradually, and soon attained a maximum, which it did not surpass, however long the contact of the pile with the conducting wire was continued. This maximum or permanent, state was obtained in 0'024 of a second of time (the galvanometer then marking 19 50'), in four lines of different lengths. The experiments were made during very fine weather, from 10 to 12 o'clock at night, from the 4th to the 6th of October, 1S59, on a telegraph circuit of 104 leagues in length, passing from Nancy to Strasbourg, Malhouse and Vesul, back to Nancy. ANALYSIS OF INDUCTION SPARKS. M. Moncel, of France, affirms, as the result of his experiments, that the induced spark is not homogeneous, but consists of the original discharge, and of a secondary discharge through a luminous atmosphere, which is generated by the heating and ratification of the adjacent air. He also states that the discharge through this luminous atmosphere exhibits the most striking calorific effects ; while the original discharge possesses the proper- ties of frictional electricity. By employing a microscope to examine the induction spark, he satisfied himself that the luminous atmosphere was only a miniature representation of the induction light seen in a vacuum ; con- tinuing his investigations, he succeeded in detecting in the luminous atmos- phere which accompanies the spark when the discharge takes place in common air, the stratifications which are so remarkable in the hydrogen vacuum. In this experiment he caused the discharge to traverse the flame of a wax candle, when the light of the negative pole, instead of being blue, as in the hydrogen vacuum, was a brilliant Avhitc, owing to the presence of carbonaceous particles. When one of the rheophores is plunged into water, NATURAL PHILOSOPHY. 113 and the discharge taken through the fluid, some curious effects take place, modified according to which pole is immersed, but in each case the luminous atmosphere exhibits singular corruscations. When the rheophores are sepa- rated, so that the direct discharge cannot take place, the effects of the luminous atmosphere are still more conspicuous. ELECTRICAL ACTION OF THE TORPEDO. From the results of some experiments recently published by M. Matteucei, we learn that the electro-motive power of the organ of the torpedo exists independently of the immediate action of the nervous system. If a section of the electric organ of the torpedo which has been dead forty -eight hours, or if the torpedo be exposed for the same number of hours to the action of the open air, or left for twenty-four hours in a frigorific mixture, where it may have hardened or become frozen, or if kept during the latter period in water at a temperature from 104 to 122, be made to communicate with a galvanometer, a great deviation will be produced. If the torpedo be killed with the poison curare or woorali, it will present the same electro-motive power as if it had. died naturally. In its operations as a nerve-discharging battery, its electro-motive power is considerably increased under stimulated action. When the nerves of the organs have been several times excited in succession, that power for which the torpedo is so remarkable is greatly increased, and will produce a greater number of discharges than it would in its normal condition. For instance: Let two pieces of equal dimensions, each containing a strong nervous filament, be prepared of one of the organs of a torpedo; let them be placed on a piece of gutta-percha, with the two nerves opposite to each other, and situated perpendicularly to the prisms of a thermo-electric apparatus; on closing the circuit of the galvanometer, a small differential current becomes apparent, but soon disappears. Then if the nerve of a galvanoscopic frog be placed upon each organ, and the circuit be broken under a mercury bath while the nerve of one of the pieces is being irritated with the points of a fine pair of scissors, the frog then in contact with that piece will exhibit violent convulsions. When after this the nerve is left at rest, and the circuit of the galvanometer again closed, a strong deviation, which lasts a long time, is perceived in the direction of the excited organ. The electro-motive power of the organ of a torpedo is not influenced by the nature of any gaseous medium in which it may be left for twenty-four hours. This is proved by comparing, in opposition to each other, two pieces preserved in different gases, such as hydrogen, oxygen, carbonic acid, and atmospheric air more or less rarefied; when it will appear that there is no constant difference between the electro-motive powers of the two pieces. WEAVING BY ELECTRO-MAGNETISM. In the improvement of the old weaving machine, effected by Jacquard, under the encouragement of the first Napoleon, the pattern of the design was pricked on large perforated cards, which went in an endless chain round a roller in the centre of the loom. All the threads of the warp were connected with bars in the upper part of the loom, and these, by a movement of the weaver's treadle, were piished against the perforated cards. Those which faced the pattern holes, and therefore corresponded with them, remained there, and so, when the lever was lowered, held up the threads which ought 10* 114 ANNUAL OF SCIENTIFIC DISCOVERY. to have been raised, and allowed the shuttle to weave in the weft or pattern between. This machine was an immense improvement on the old affair; yet, though always continuing the best, it had its own peculiar drawbacks. Thus, a put- tern for a damask curtain or tablecloth, of a rich or elaborate design, we will say, required from twenty thousand to twenty-five thousand cards. To pro- duce these occupied men from two to four, six, or even eight months, ac- eording to the greater or less intricacy of the design, and cost from six hun- dred to nine hundred dollars. As a matter of course, therefore, designs were made as simple and plain as possible, were not often changed, and never until the trade would no longer take them. M. Bonelli at once sets aside all this by the nse of electricity. The little bobbins or bars which hold up the threads of the warp in the Jacquard loom he makes into electro-magnets in the usual way. The design is painted on a sheet of tinfoil, with the portions not used in the pattern covered with a non- conducting varnish. The pattern passes slowly over a roller under an im- mense number of brass teeth, communicating by fine insulated Avires with the bobbins, the pattern of course being in connection with one pole of the battery, and the bobbins, or magnets, with the other. Thus, as the tinfoil slowly moves round, the parts which are not to be worked, being covered with a non-conducting varnish, transmit no current through the brass teeth to the bobbins. The pattern, or exposed portion of the tinfoil, on the con- trary, does so, and transforms the bobbins into electro-magnets, which attract and hold the bars opposite their points attached to the threads of the warp, and these bars being thus held up for an instant, of course raise the threads of the warp below, and allow the shuttle to weave in a particular pattern. This is merely a very rough and general outline of the old and new plans. The latter, however, is far too important to be thus disposed of in a few words. What we have already said will, nevertheless, assist our readers to comprehend the details of this most valuable improvement. The electric loom, as it is termed, was invented in 18-54, by the Chevalier Bonelli, of Milan, and director of the Sardinian telegraphs. The first machine, con- structed at Turin, was afterwards modified by M. Hipp, at Berne; and though it demonstrated the possibility of weaving by means of electro-magnetism, it nevertheless left much to be desired with respect to the success of its prac- tical application. It was not until 1859 that success in perfecting the ma- chinery, and in rendering it available for either hand or power-loom weaving, was attained. To fully appreciate all the advantages which this application of electricity to the manufacture of woven material must produce, it is neces- sary always to keep in mind the long and costly operations which, as we have said, are now incurred before commencing weaving in one or two colors. Firstly, then, in weaving by the old machine, we must remember the design is drawn on paper divided into a multitude of little sqiiares, the horizontal series representing the weft, or pattern ; the cross, or short series, the warp, or substance of the material woven. Secondly, the design must be "read; " that is, the punches of the stamping machine, which are equal in number to the small squares of the pattern, must be arranged so as to perforate the cards, which, as AVC have shown, form the basis of the present Jacquard system. Each of these operations must be repeated as many times as there are horizontal lines in the design, which merely represents one thread of NATURAL PHILOSOPHY. the weft, as there must be as many cards as there are wefts or cross-threads in a pattern. Lastly, all the cards must be sewn together in the order of their succession. AVe have already shown how in the " Jacquard " these pierced cards act on the pins of the loom, and determine the raising of the threads of the warp or basis of the material beneath. M. Bonelli's looms instantly accomplish all this work we have been describing, with an exacti- tude that could never be obtained from " the cards," which, as our readers will easily understand, \vere almost incapable of producing a very complex pattern. It is by passing the thread of the weft over or under the thread of the warp that the design, either in one or many colors, is produced. The design in M. Bonelli's plan is traced on a sheet of tinfoil, the pattern remain- ing in bright metal, while all the rest is painted over with a non-conducting varnish. The metal pattern thus becomes the conductor of the electricity ; the varnished portions do not. This thin sheet of tinfoil is placed on a roller, which revolves it by very slow degrees, with a uniform movement, iinder a metallic comb. This comb contains teeth equal in number to the pins of a Jacquard loom, from four hundred to six hundred, each of which is most carefully insulated from the next, and each connected by a fine wire with a small electro-magnet or bobbin. A wire from a small Bunsen pile is connected with this comb and electro-magnets, the other wire with the tinfoil design. When by the ordinary movement of the Jacquard loom, effected by the foot of the workman pressing the treadles, the loom moves, the metallic comb lowers itself, and comes in contact with the tinfoil sheet of the design. The teeth of the comb touching on the varnished portions, of course, stop the passage of an electric current to the bars with which they communicate, and which, in fact, therefore remain mere bobbins. Ail those, on the contrary, which touch the metallic parts of the sheet the design, in fact allow the current to pass to the electro-magnets, which instantly become active, and capable of attracting little horizontal bars of iron, which are arranged with their points towards the magnets in a frame common to them all. Those magnets, therefore, which are active, at once attract and retain the bars as the frame, all by a simple movement, in a second, moves a little back and lowers, and thus the threads of the warp below, which are attached to crochet- needles hanging on to the magnetized bars, are raised, and the shuttle with the weft of the pattern-thread passes in between them. There is a little mechanical contrivance employed to give solidity to the arrangement of the bars, a solidity which is necessary, as the magnetized bars have to act upon the needles of the loom, and keep them and their threads suspended. Such are the chief features of this electro-magnetic weaving machine, which, apart from its scientific merits, contains, in addi- tion, some most admirable mechanical contrivances. Such, for instance, is the ingenious means by which the design-sheet moves with a speed variable at will, and either backwards or forwards, and the addition of a little brush to clean the comb. This last, at each motion of the loom, sweeps across all its teeth, to prevent the injurious action of the dust, which, falling upon the surface, would soon interfere with the action of the electric fluid. The loom which we have now described is only applicable to stutfs of two colors ; that is to say, of one color upon one general ground. But a loom capable of weaving stuffs of six, eight, or ten colors, only differs by the addition of a most simple piece of mechanism, thus : Each of the different colors is insulated from the other, and along them, on the pattern, the pole of the bat- 116 ANNUAL OF SCIENTIFIC DISCOVERT. tory slowly passes as the weaver works the machine with his feet, transmit- ting the current to each color in the order in which they occur. Thus, of course, the current is sent through the comb to the electro-mag- nets, which raise the thread of the warp below, where the weaver has his color-slnittli-s arranged in the order in which they are to be used, and throws them in accordingly. So the loom just as easily, and on the same principle, transmits the pattern to a stuff of twelve colors as to that of only two. It is in this that the weaving by electricity displays its superiority over the pre- sent system, according to which, for example, if a material is to be worked in six colors, it is necessary by the Jacquard loom to employ six times more cards than for a similar design of one color. The advantages, therefore, which ought to result from the introduction of the electro-magnetic loom in the manufacture of all our patterned fabrics are sufficiently apparent. A new method, which does away with all the operations necessary to the pre- paration of the cards, must, of course, produce an all-important saving of both time and money upon the present system of manufacture. But there are other and not unimportant advantages, such, for instance, as permitting all manufacturers to try the effect of new patterns without going through the long and costly process of preparing cards. He can ascertain in a few hours the effect of any design, and prepare a series of specimens for the approbation of the trade before commencing upon a single yard of stuff. In short, whatever can be done by printing, lithographing, or engraving, can be thus stamped on tinfoil, and reproduced in colored silks, according to the colors of the original, with all the fidelity of an electrotype. By this means, at a trifling cost, families can have special designs, such as crests and initials, for carpeting, curtains, furniture covers, etc., at a week's notice. In this loom also the workman is enabled, with the greatest facility, to effect a reduction of the design, by means of varying the speed of the cylinder on which the pattern is placed. Without alteration, or without touching the design, it can with equal facility make stuffs more or less strong or more or less light, by changing the number of the threads of the weft, and by regulating, in accordance with that change, the speed of the cylinder on which the pattern revolves. Of course, any required additional effect can be made, or any part omitted from the design, without at all interfering with the workman. As a matter of course, the electrical portions of the invention are capable of application to any loom, and, in fact, occupy, at the top of the machine, no more space than a small writing-desk. It is only the cards and cumbrous accessories of the Jacquard loom which are done away with; its mechanical properties are retained, and the electro-magnets can be applied to any. It is expected that with this machine, in all very large or intricate pat- terns, such as are now occasionally used in silks, a saving of eighty per cent in money, and more than eighty per cent in time, will be gained upon the production of similar designs by the present system. ON THE INFLUENCE OF MAGNETIC FORCE ON THE ELECTRIC DISCHARGE. The following is an abstract of a lecture recently delivered before the Royal Institution, Great Britain, by Professor Tyndall, which was intended to illus- trate the constitution of the electric discharge, and of the action of magnetism upon it : 1. The influence of the transport of particles was first shown by an experi- NATURAL PHILOSOPHY. 117 merit suggested, it was believed, by Sir John Hcrschcl, and performed by Professor Daniell. The carbon terminals of a battery of forty cells of Grove were brought within one eighth of an inch of each other, and the spark from a Leyden jar was sent across this space. This spark bridged with carbon particles the gap which had previously existed in the circuit, and the bril- liant electric light due to the passage of the battery current was immediately displayed. 2. The magnified image of the coal points of an electric lamp was pro- jected upon a white screen, and the distance to which they could be drawn apart without interrupting the current was noted. A button of pure silver was then introduced in place of the positive carbon, a luminous discharge four or five times the length of the former being thus obtained. The silver was first observed to glow, and afterwards to pass into a state of violent ebulli- tion. A narrow dark space was observed to surround one of the poles, cor- responding probably with the dark space observed in the discharge of Ruhm- korff's coil through rarefied media. 3. The action of a magnet upon the splendid stream of green light obtained in the foregoing experiment was exhibited. A small horseshoe magnet of Logemann was caused to approach the light, which was bent hither and thither, according as the poles of the magnet changed their position: the discharge in some cases formed a magnificent green bow, which on the fur- ther approach of the magnet was torn asunder, and the passage of the cur- rent thereby interrupted. It was Davy who first showed the action of a magnet upon the voltaic arc. The transport of matter by the current was further illustrated by a series of deposits on glass obtained by Mr. Gassiot from the continued discharge of an induction coil.* 4. A discharge from RtihmkorfT's .coil was sent through an attenuated medium and the glow which surrounded the negative electrode was referred to. One of the most remarkable effects hitherto observed was that of a magnet upon this negative light. PI ticker had shown that it arranges itself under the influence of the magnet exactly in the direction of the magnetic curves. Iron-filings strewn in space, and withdrawn from the action of grav- ity, would arrange themselves around a magnet exactly in the manner of the negative light. An electric lamp was placed upon its back; a horseshoe magnet was placed horizontally over its lens, and on the magnet a plate of glass: a mirror inclined at an angle of 45 received the beam from the lamp, and projected it upon the screen. Iron-filings were scattered on the glass, and the magnetic curves thus illuminated were magnified, and brought to clear definition upon the screen. The negative light above referred to arranges itself, according to Pliicker, in a similar manner. 5. The rotation of an electric current round the pole of a magnet, dis- covered by Mr. Faraday in the Royal Institution, nearly forty years ago, was next shown; and the rotation of a luminous current from an induction coil in an exhausted receiver, by the same magnet, was also exhibited, and both shown to obey the same laws. 6. Into a circuit of twenty cells a large coil of copper wire was introduced, and when the current was interrupted, a bright spark, due to the passage of the extra current, was obtained. The brightness and loudness of the spark were augmented when a core of soft iron was placed within the coil. The disruption of the current took place between the poles of an electro-magnet; and when the latter was excited, an extraordinary augmentation of thekv.irl- HCSS of the spark was noticed. This effect was first obtained by Page, and 118 ANNUAL OF SCIENTIFIC DISCOVERY. was for a time thought to denote a new property of the electric current. But Rijkc had shown in a paper, the interest of which is by no means less- oned bv the modesty with which it is written, that the effect observed by 1'age is due to the sudden extinction of the primary spark by the magnet; which suddenness concentrates the entire force of the extra current into a moment of time. Speaking figuratively, it was the concentration of what, under ordinary circumstances, is a mere push, into a sudden kick of projec- tile energy. 7. The contact-breaker of an induction coil was removed, and a current from five cells was sent through the primary wire. The terminals of the secondary wire being brought very close to each other, when the primary was broken by the hand, a minute spark passed between the terminals of the secondary. When the disruption of the primary was effected between the poles of an excited electro-magnet, the small spark was greatly augmented in brilliancy. The terminals were next drawn nearly an inch apart. When the primary was broken between the excited magnetic poles, the spark from, the secondary jumped across this interval, whereas it was incompetent to cross one-fourth of the space when the magnet was not excited. This result was also obtained by Rijkc; who rightly showed, that in this case also the augmented energy of the secondary current was due to the augmented speed of extinction of the primary spark between the excited poles. This.experi- mcnt illustrated in a most forcible manner the important influence which the mode of breaking contact may have upon the efficacy of an induction coil. The splendid effects obtained from the discharge of Ruhmkorff's coil through exhausted tubes were next referred to. The presence of the coil had compli- cated the theoretic views of philosophers, with regard to the origin of those effects ; the intermittent action of the contact-breaker, the primary and second- ary currents, and their mutual reactions, producing tertiary and other currents of a higher order, had been more or less invoked by theorists, to account for the effects observed. Mr. Gassiot was the first to urge, with a water battery of three thousand five hundred cells, a voltaic spark across a space of air, before bringing the electrodes into contact; with the self-same battery he had ob- tained discharges through exhausted tubes, which exhibited all the pheno- mena hitherto observed with the induction coil. He thus swept away a host of unnecessary complications which had entered into the speculations of theorists upon this subject. 8. On the present occasion, through the kindness of Mr. Gassiot, the speaker was enabled to illustrate the subject by means of a battery of four hundred of Grove's cells. The tension at the ends of the battery was first shown by an ordinary gold-leaf electroscope ; one end of the battery being insulated, a wire from the other end was connected with the electroscope; the leaves diverged ; on now connecting the other end of the battery with the earth, the tension of the end connected with the electrometer rose, ac- cording to a well-known law, and the divergence was greatly augmented. 9. A large receiver, in which a vacuum had been obtained by filling it with carbonic acid gas, exhausting it, and permitting the residue to be absorbed by caustic potash, was placed equatorially between the poles of the large electro-magnet. The jar was about six inches wide, and the distance be- tween its electrodes was ten inches. The negative electrode consisted of a copper disk, four inches in diameter; the positive one was a brass wire. An accident had recently occurred to this jar. Mr. Faraday, Mr. Gassiot, and the speaker had been observing the discharge of the nitric acid battery NATURAL PHILOSOPHY. 119 through it. Stratified discharges passed when the ends of the batteiy wero connected with the electrodes of the receiver; and on one occasion the dis- charge exhibited an extraordinary effulgence; the positive wire emitted light of dazzling brightness, and finally gave evidence of fusion. On intcr- terrupting the circuit, the positive wire was found to be shortened about half an inch, its metal having been scattered by the discharge over the interior surface of the tube. 10. The receiver in this condition was placed before the audience, in the position mentioned above. When the ends of the four-hundred-cell battery were connected with the wires of the receiver, no discharge passed ; but on touching momentarily with the finger any portion of the wire between the positive electrode of the receiver and the positive pole of the battery, a brilliant discharge instantly passed, and continued as long as the connection with the battery was maintained. This experiment was several times re- peated: the connection with the ends of the battery was not sufficient to produce the discharge, but in all cases the touching of the positive wire caused the discharge to flash through the receiver. Previous to the fusion of the wire above referred to, this discharge usually exhibited fine stratifi- cation : its general character now was that of a steady glow, through which, however, intermittent luminous gushes took place, each of which presented the stratified appearance. 11. On exciting the magnet between whose poles the receiver was placed, the steady glow curved up or down, according to the polarity of the mag- net, and resolved itself into a scries of effulgent transverse bars of light. These appeared to travel from the positive wire along the surface of the jar. The deflected luminous current was finally extinguished by the action of the magnet. 12. When the circuit of the magnet was made and immediately inter- rupted, the appearance of the discharge was extremely singular. At first the strata rushed from the positive electrode along the upper surface of the jar, then stopped, and appeared to return upon their former track, and pass successively with a deliberate motion into the positive electrode. They were perfectly detached from each other; and their successive ingulfments at the positive electrode were so slow as to be capable of being counted aloud with the greatest ease. This deliberate retreat of the strata towards the positive pole was due, no doubt, to the gradual subsidence of the power of the magnet. Artificial means might probably be devised to render the re- cession of the discharge still slower. The rise of power in the magnet was also beautifully indicated by the deportment of the current. After the cur- rent had been once quenched, as long as the magnet remained excited no discharge passed; but on breaking the magnet circuit, the luminous glow reappeared. Not only, then, is there an action of the magnet upon the par- ticles transported by an electric current, but the above experiment indicates that there is an action of the magnet upon the electrodes themselves, which actually prevents the escape of their particles. The influence of the magnet upon the electrode would thus appear to be prior to the passage of the current. 13. The discharge of the battery was finally sent through a tube, whose platinum wires were terminated by two small balls of carbon: a glow was first produced; but on heating a portion of the tube containing a stick of caustic potash, the positive ball sent out a luminous protrusion, which sub- 120 ANNUAL OF SCIENTIFIC DISCOVERY. scquently detached itself from the ball; the tube becoming instantly after- wards filled with the most brilliant strata. There can be no doubt that the superior effulgence of the bands obtained with this tube is due to the character of its electrodes; the bands are the transported matter of these electrodes. May not this be the case with other electrodes? There appears to be no uniform flow in nature; we cannot get cither air or water through an orifice in a uniform stream; the friction nirainst the orifice is overcome by starts, and the jet issues in pulsations. Let a lighted candle be quickly passed through the air; the flame will break itself into a beaded line in virtue of a similar intermittent action, and it may be made to sing, so regular are the pulses produced by its passage. Analogy miii'ht lead us to suppose that the electricity overcomes the resistance at the surface of its electrode in a similar manner, escaping from it in tremors ; the matter which it carries along with it being broken up into strata, as liquid vein is broken into drops. ON THE ORIGIN OF ATMOSPHERIC ELECTRICITY. It is well known that the earth is, relatively to the air, negatively electri- fied. If a bar of polished metal be held horizontally, no electrical phenom- ena are manifested, but when it is turned to a vertical direction at once the lower extremity becomes positively electrified, and the upper negatively. This takes place evidently by induction. So in a thunder-storm. The air at the surface, becoming abnormally heated and moist, comes to be in a state of tottering equilibrium, in which state the slightest disturbance will throw it rolling over and over, and, rising into colder regions, it condenses and falls as rain. The rising column, like the bar before mentioned, becomes at bot- tom charged with positive electricity, and at the top with negative; and the thunder-cloud becomes, in fact, two, one above the other, which Mr. Wise, the aeronaut, has often seen and described. Between these, filled with oppo- site electricities, a gigantic spark passes, which is the forked lightning. Thus the conclusion is that atmospheric electricity is due to induction from, the earth. Prof. Henry. / NEW SECONDARY TILE OF GREAT IWYER. BY M. G. TLANTE. Jacobi proposed recently the use of secondary electric currents for tele- graphic purposes, and Plante" had suggested the substitution of electrodes of lead for those of platinum in these batteries. A more extended study has convinced him of their use. He states that a battery with electrodes of lead has two and a half times the electro-motive force of one with electrodes of platinized platinum, and six times as great as that of one with ordinary plati- num. This great power arises from the powerful affinity which peroxide of lead has for hydrogen, a fact first noticed by De la Rive. The secondary battery which he recommends has the following construction: It con- si-ts of nine elements, presenting a total surface of ten square metres. Each clement is formed of two large lead plates, rolled into a spiral, and separated by coarse cloth, and immersed in water acidulated with one-tenth sulphuric, acid. The kind of current used to excite this battery depends on the manner in which the secondary couples are arranged. If they are arranged so as to give three elements of triple surface, live small Bunsen's cells, the zincs of which are immersed to a depth of seven centimetres, arc sufficient NATURAL PHILOSOPHY. 121 to give, after a few minutes' action, a spark of extraordinary intensity when the current is closed. The apparatus plays, in fact, just the part of a con- denser; for by its means the work performed by a battery, after the lapse of a certain time, may be collected in an instant. An idea of the intensity of the charge will be obtained by remembering that to produce a similar effect it would be necessary to arrange three hundred Bunsen's elements of the ordinary size (thirteen centinietres in height), so as to form four or five elements of three and a half square metres of surface, or three elements of still greater surface. If the secondary battery be arranged for intensity, the principal battery should be formed of a number of elements sufficient to overcome the inverse electro-motive force developed. For nine secondary elements, about fifteen Bunsen's cells should be taken, which might, how- ever, be very small. From the malleability of the metal of which it is formed, this battery is readily constructed ; by taking the plates of lead sufficiently thin, a large surface may be placed in a small space. The nine elements used by Plante are placed in a box thirty-six centimetres square, filled with liquid once for all, and placed in closed jars ; they may also be kept charged in a physical cabinet, and ready to be used whenever it is desired to procure, by means of a weak battery, powerful discharges of dynamic electricity. Comptes Rcndus, March 26th, 1860. EFFECT OF PRESSURE ON ELECTRO-CONDUCTING POWER. M. Elie Wartmann has found experimentally that the electric conductibility of copper wire is sensibly diminished by a pressure of fifty atmospheres, that this diminution increases with the pressure, and disappears when the pressure is relieved. The experiments were carried up to four hundred atmospheres. These results establish a new analogy between heat, light, and electricity. L'1/tstitut. ON THE TRANSMISSION OF ELECTRIC EFFECTS ACROSS WATER WITHOUT THE AID OF TRANSVERSE WIRES. At the Aberdeen meeting of the British Association, 18-39, Mr. Lindsay, of Dundee, stated that he commenced experimenting in 1814 in telegraphing across water, without wires first, and then by means of two uninsulated wires ; and finding the latter method much more powerful, he preferred it, and tele- graphed in that way through several ponds in Dundee. In 1852 he resumed experiments without transverse wires. In 18-33 he made experiments on a larger scale at Portsmouth, and succeeded in crossing more than a quarter of a mile. More recently he had made additional experiments, and succeeded in crossing the Tay where it was three-quarters of a mile broad. His method ' had always been to immerse two plates or sheets of metal on the one side, and connect them by a wire passing through a coil to move a needle, and to have on the other side two sheets similarly connected, and nearly opposite the two former. Experiments had shown that only a fractional part of the electricity generated goes across, and that the quantity that thus goes across can be increassed in four ways: first, by an increase of battery power; second, by increasing the surface of the immersed sheet; third, by increas- ing the coil that moves the receiving needle; and fourth, by increasing the lateral distance. In cases where lateral distance could be got, he recom- 11 122 ANNUAL OF SCIENTIFIC DISCOVERY. mended increasing it, as by that means a smaller battery was requisite. In telegraphs by this method to Ireland or France, abundance of lateral distance* could be got; but for America the lateral distance in Britain was much less than the distance across. In the greater part of his experiments the distance at the side had been double the distance across; but in the experiment across the Tay the lateral distance was the smaller, being only about half a mile, while the distance across was three-quarters of a mile. Of the four elements above mentioned, he thought that if any one were doubled, the quantity of electricity that crossed would also be doubled; and if all the elements were doubled, the quantity transmitted would be eight times as great. In the ex- periment across the Tay the battery-power was of four square feet of zinc; the immersed sheets contained about ninety square feet; the weight of the copper coil was about six pounds; the lateral distance was less than the transverse distance, but if it had been a mile, and the distance across also a mile, the signal would no doubt have been equally distinct. Should the above law (when the lateral distance is equal to the transverse) be found cor- rect, the following table might thus be formed: Zinc for battery. Immersed sheets. Coil. Distance crossed. Square feet. Square feet. Pounds. Miles. 4 90 6 1 8 180 12 8 16 360 24 64 32 720 48 512 64 1440 96 4096 128 2880 192 32,768 But supposing the lateral distance to be only half the transverse, then the distance crossed might be sixteen thousand miles; and if it was only a fourth, then there would be eight thousand miles, and thus a greater distance than the breadth of the Atlantic. Further experiments were, however, necessary to determine the law. On the battery side he had made the electricity pass through a coil of thick wire, and on the receiving side through one of small wire; and when a battery and receiver were on each side, by means of a shifter of communication, the path for sending was through the thick wire, and for receiving through the small. Since this last experiment he had increased the coil, and thought there was power to transmit signals for two miles. According to this calculation, he thought a battery of one hundred and thirty square feet, immersed sheets of three thousand square feet, a coil of two hundred pounds weight, were sufficient to cross the Atlantic, with the lateral distance that could be obtained in Great Britain. In the course of the discussion Sir D. Brewster said that he was a member of the committee entrusted with the experiments alluded to by Lord Rosse during the Great Exhibition. The result was this : they sent messages across the Serpentine in the usual way; the wire was then broken. With a gap of six feet the messages still went, and when the distance was increased to six- teen and twenty feet they still went. Experiments of Mr. Beardmore.^lv. S. Beardmore, a civil-engineer of London, has recently published a pamphlet on the subject of the applicability of terra-voltaism to submarine telegraphs, in which he gives an account of some hopeful experiments made by him between Cromer and Heligoland, through a line three hundred miles in length. He employed a simple terra- voltaic apparatus, such as he seems convinced must ultimately be used for NATURAL PHILOSOPHY. 123 * t long submarine telegraphs, instead of the battery system heretofore in use. The new apparatus consists merely of a couple of earth plates, positive and negative, one at either extremity of the line, no other battery being used. By such means it is anticipated that all necessity for insulation of the wires, or at least dependence on perfect insulation, will be. obviated, the electricity evolved by a single voltaic couple, while connected with the respective ends of the wire, having no tendenc} T to escape to the earth during transit. The chief difficulty i-elates to the question of intensity, as by the single arrangement increase of surface only affords increase of quality, and not of intensity, as by the battery method. Mr. Beardmore thinks that the present sub-Atlantic cable would prove to be not wholly useless, if efforts were made to work it on his terra-voltaic principle. ON THE GREAT AURORAS OF AUGUST AND SEPTEMBER, 1859. Professor Loomis, in a paper on the great auroras of August and Septem- ber, 18-39, read before the American Association for I860, characterized the display as unsurpassed by any on record for magnificence and geographical extent. The disturbance of the magnetic instruments was well-nigh unpre- cedented for violence, and it may be safely asserted that the phenomena ex- tended over the entire circuit of the globe. The aurora of September 2d formed a belt of light encircling the northern hemisphere, extending southward in America to latitude 22, and reaching to an unknown distance on the north; until it pervaded an interval between the elevation of fifty and five hundred miles above the earth's surface. The illumination consisted chiefly of lumi- nous beams or columns everywhere parallel to the direction of a magnetic needle freely suspended. These beams were about five hundred miles in length, and their diameter varied from, five to ten or twenty miles, and were, perhaps, sometimes still greater. IMPROVED GALYANO-PLASTC PROCESS. An improvement in the method of producing copies of busts, statues, groups, and round ornaments, by the galvano-plastic process, has just been made public. The principle of the invention is the use of conductors so arranged as to spread the electrical current over a large surface. The modes of applying it differ according to circumstances. One plan is as follows : A piece of copper, or of charcoal, is made to represent in miniature the form in outline of the object to be reproduced; this miniature conductor is attached to the negative pole, and then introduced into the interior of the mould, which, of course, is in connection with the same pole ; the whole is then plunged together in the bath. The metal is conducted by the various points of this miniature conductor towards all the various hollows which correspond with its prominences. This, however, was but a rude form of the methods adopted. The inventor, M. Lenoir, afterwards substituted for the miniature above described a light frame or mass formed of metallic wire, or of any other conducting material, which he introduced in the same manner into the hollow of the mould; by this means he obtained a large number of conductors, which approached every portion of the interior of the mould, and formed what he calls a mass of nerves for conducting the electricity into the most intricate portions of the hollow mould. These wires also render the decomposition of the solution unusually active, so much so that the 124 ANNUAL OF SCIENTIFIC DISCOVERY. gas liberated rises constantly to the surface in large heads. The deposit, however, is made with perfect regularity and uniformity. PROTECTION OF SILVERED SURFACES- Baron von Liebig has patented certain improvements in protecting: the sil- vered surfaces of mirrors and other articles of glass. This method consists in preparing the silvered surface, by depositing thereon a coating of copper, gold, or other metal, by electro-galvanic action, combined with the use of a neutral solution of the double salt tartrate of the oxide of copper, and soda, potash, or ammonia. DURABILITY OF ELECTROTYPE WORK. Mr. E. Richardson, in a communication to the Builder, London, gives the following information as to the probable durability of electrotype metal, and its thickness. Mr. Richardson states that in 1844, being called upon to fur- nish metal medallions, etc., for the granite testimonial to General Sir Alex- ander Dickson, on Woolwich-common, a very exposed situation, he sug- gested electrotype castings. A consultation of officers on the question fol- lowed, the results being full permission to reproduce the models in electro- type copper, which was ably executed. These castings were at that time of unusual size and thickness, namely, two feet six inches diameter, and fully an eighth of an inch thick of solid metal. This was effected also without sin-inking, and every tool-touch from the clay model was reproduced. These works have been now exposed for fifteen years. They weighed, Mr. Rich- ardson believes, thirty pounds each. No chasing was required. On the other hand, Mr. Richardson has had for years a small brass, about fifteen inches high, produced by the old fire-process, which, cost pounds to chase, obliterating every line of his original model, and weighing nearly a quarter of a hundredweight. NEW APPLICATION OF ELECTRO-METALLURGY. Among the recent applications of electro-metallurgy we may instance the happy idea of Mr. Gaudin of employing it in setting jewels. This is a very delicate and expensive branch of jewelry, and so difficult that the setting of a jewel can seldom be fully relied upon. The inventor first takes a mould in wax of the ornament that is to receive the jewels, then places on it, at the proper points, the jewels, embedded in the wax to a sufficient depth; the wax model, rendered a conductor of electricity, is placed in the gold solu- tion, and the metal deposited upon it. When the deposit is completed, the jewel is found firmly enchased in the metal, from which, if the process has been properly conducted, it will be impossible for the jewel to escape. The saving of time effected by this process is also very considerable. By the or- dinary process a jeweller can scarcely set sixty jewels in a day, but by the new process he can set as many as fifteen hundred to two thousand in a day. LAST OF THE ATLANTIC CABLE. During the past summer, several attempts have been made to elevate and recover the American end of the Transatlantic telegraph ; but in every in- NATURAL PHILOSOPHY. 125 stance in which it was hooked up to the surface it soon broke, and was finally abandoned. The following extracts from the log of the party em- ployed will, however, be read with interest, as the last transaction connected with this gigantic but unfortunate enterprise : On the 12th of June, Captain Kell succeeded in fishing up and buoying the end, after recovering three-quarters of a mile of the cable. On the 14th operations were resumed, and three miles and a half of cable recovered, when a fracture occurred. On the 23d the cable was hooked in ninety fathoms, and parted both ways, the bight and a short piece of cable coming on board. 25th. The cable was hooked again, but parted when within fifteen fathoms of the surface, as it had done on several previous occasions. 27th. Grapnelling was resumed in one hundred and fourteen fathoms; the cable was hooked several times, and with one exception parted before reach- ing the surface. Care was taken to buoy the spot the moment the cable broke, and by grapnelling from a quarter to half a mile east of the buoy we hoped to succeed in raising the bight, and did at last get it on board. On testing the cable towards Ireland, it was found to be broken a very short dis- tance from the vessel, three-quarters of a mile of cable being recovered before it parted again at a weak place. 28th. The wind and sea too high for working. A fresh consultation was held as to the best mode of proceeding, and it was resolved to go further out at once, hoping thereby to avoid the rocky ground and the bad state of the cable. 30th. The cable was hooked three times from the steamer, in one hundred and thirty fathoms of water, but broke before reaching the surface. At last a bight came on board, the cable at this spot being unusually good for about thirty yards; the outer end was found to be broken about two hundred yards off. About two miles of the inner end were recovered, when it parted again at a weak place, where there was nothing but the gutta percha covered wire left; this, however, was just able to bring the cable to the surface, when it snapped before it could be secured by a stopper. Although mud is shown on the charts, there are most unquestionably rocks also, as was too plainly indi- cated by the state of the cable, rock weed and sea animalcules adhering to and surrounding it in many places, showing that it had been suspended clear of the bottom. The cable was invariably hauled in by hand to avoid unneces- sary strain. The recovered cable varied in condition very much, and what is most important is, that even those portions which came out of the black mud were so perished in numerous patches that the outer covering parted on board, during the process of hauling in, and but for the dexterity and cour- age of the men in seizing hold of it beyond the break, Avhere the iron wires stuck out like bunches of highly-sharpened needle points, we should not have known so much of its condition. In a word, it was evidently sometimes em- bedded in mud, sometimes on small stones, sometimes half embedded, and sometimes wholly exposed over rocks, as was apparent from the condition of the outer covering. The iron wires in many places often appeared sound, but, on minute inspection, were found eaten away and rotten; the sewing was also decayed. In some places the iron wires were coated with metallic copper, and much eaten, they having most probably rested upon copper ore, for there are veins of it in Trinity Bay. The gutta percha and copper wire are, however, in as good condition as when laid down. The general ragged, precipitous, and rocky character of the surrounding 11* 12(5 ANNUAL OF SCIENTIFIC DISCOVEUY. land evidently extends below the surface of the water; the nncvomicss of our soundings and condition of the cable indicate this most plainly. We accordingly decided upon leaving the neighborhood of Bull's Island alto- gether, as the cable in its present state at that part of the bay will not repay the cost of recovery. We agreed simultaneously to attempt to raise the cable off Heart's Content, and ascertain its condition there; this being the most promising part of the bay, from the information we have been able to collect. Accordingly, on the 1st of July, we sailed to this locality, and grap- nelled for the cable in smooth water. We finally hooked it, in one hundred and forty-three fathoms water, some four times or more. It sometimes lifted off the ground before parting as much as forty fathoms, sometimes only fifteen; in no instance did it come near the surface of the water. On two occasions the iron strands of the cable left most unmistakable impres- sions on the grapnel, and iron rust, resembling that usually found on the cable, adhered to its claws. The bottom consisted of green mud and light- colored clay, the latter very compact, and in consistency not much unlike the blue clay of London; some parts of the bottom were of stone. Having found it quite impossible to raise the cable, we concluded, after careful consideration, to make a last, but hopeless, trial at the mouth of Trinity Bay, and if unsuccessful to take the steamer and men to St. John's, to avoid further expense. On July 3d, the steamer reached Break Heart Point, a little before 4 A. M. We grapnelled for the cable from about six and a half miles off, in one hundred and sixty-five fathoms water, to within one and a half miles of the point, where the water was still over one hundred fathoms. We did not succeed in finding it ; and had we done so, the Atlantic roll setting into the bay was so heavy, and the current running out so strong, that we could not possibly have raised it to the surface, but only have deter- mined its position. It is quite possible that the cable was hooked Avithout being perceived by us, owing to the depth of water, and to the fact that the cable, especially where laid over stone, is very rotten. At six miles out, the bottom consisted of clay covered by a thin stratum of mud. At about four and a half or five miles off, the bottom appeared to consist of stones, and this continued to within one and a half miles of the. "point," where the water was very deep. Those portions of the recovered cable that were wrapped with tarred yarn were sound, the tar and hcrnp having preserved the iron wires bright and free from rust. This will be further reported on when the pieces of recovered cable have been more closely examined. ON TIIE PRESENT CONDITION OF SUBMARINE TELEGRAPHING. The unfortunate failure of the Atlantic Telegraph, with its long series of mistakes and miscalculations, has exercised, and still to a certain extent continues to exercise, a depressing influence upon all important schemes for submarine telegraphic communication. We can scarcely say that confidence in the working practicability of any Atlantic telegraph whatever, submerged along the old deep-sea route, has yet been established, while, regarding such a scheme merely in the light of an investment, a commercial speculation by which money is to be made, we need not remark how, at the present time, even the best inaugurated enterprise of the kind would soon have the grief of seeing its shares at half discount, unless the most rigid and practised caution was exercised both in the choice of route and choice of cable. In NATURAL PHILOSOPHY. 127 the meantime, during the stagnation that has engulfed all such projected schemes since the Atlantic cable was designed and lost, a great reform in the method of constructing submarine ropes has been going steadily forward. The old self-destructive principle of ponderous iron coils for deep-sea wires has been so generally abandoned, that a proposition for now reverting to their use across a sea of any length or depth would not be entertained for a moment by telegraphic engineers. To be sure, this change, which of course was, and still is, fiercely opposed by some of the wire ropcmakers, has not been brought about till the credulity and patience of shareholders were at an end, and until the bottom of the Mediterranean and other seas had been fruitlessly adorned with three or four of those leviathan coils, enduring monuments of our commercial enterprise, and of our mechanical ignorance also. Since that period only four years ago, though marking an age in the infant science of telegraphy opinions have undergone a most impor- tant change, and both contractors and engineers now often lean so strongly to very light cables, that the idea, like all good ideas, is in danger of being led into extremes, and we may see as much public money lost in trying to submerge cobwebs as was ever dragged down "fathoms deep," even by those expensive wire covered cables, big enough and heavy enough to moor an island. The results of this great alteration in the weight and strength of cables are likely soon to be practically tested on the most extensive scale, by the proportionate success or non-success of some cables which are now being manufactured in England. One is about the very lightest cable of its kind that has ever been made at all, always excepting the gutta-percha covered copper wire which was stretched aci'oss'the Black Sea to Balaklava. The other is to be a well proportioned " composite " cable, heavy and very massive, perhaps far too much so in some parts; in others, where it is proposed to be sunk some three miles down, it is, if not quite a light rope, still, with regard to lightness, an important example in the right direction. The first mentioned extremely light cable, which will weigh less than three hundredweight per mile in water, is about being constructed at the Electric Cable Company's works, Milwall. The heavier, and we must also say the more expensively proportioned, rope is in progress of manufacture at Glass & Elliot's for the English government, and will, it is hoped, unite England with Gibraltar. In this cable all questions of cost have been con- sidered at the treasury as entirely subordinate to procuring the very best workmanship and material, the highest conditions of mechanical and electrical excellence which it is possible to secure by money, toil, or inge- nuity. The direct route from England to Gibraltar would, for the most part, lie through what in telegraphic works would be called deep water, the route from Brest to Finisterre, and so on round the coast of Portugal, at a comparatively short distance from land, averaging on the whole either one thousand or more than one thousand fathoms. But in this cable (as should have been the case with every one that has ever been made) the contract with Glass & Elliot is not only for its manufacture on a certain plan, but for submerging it successfully. The depth of water in which it will ultimately be laid will therefore, doubtless, rest in a gi-eat measure with the contractors; subject, of course, to certain conditions of the government, that it shall be sunk in water deep enough to keep it out of the reach of any enemy, either to raise or to break. The latter consideration is, of course, one of the last importance; since only in war time will attempts be made to injure it, and 128 ANNUAL OF SCIENTIFIC DISCOVERT. in war time, above all others, its services would be absolutely indispensable to the country. Before the form, weight, strength, and outer covering of each portion of the cable were resolved on, the Board of Trade took the utmost pains, by consulting our chief electricians, to ascertain the kinds best suited for the purpose and for long endurance under water. Researches into these matters have led to the adoption of a cable of different thicknesses, weights, and strengths, according as the depth of the water under which it will be laid increases; the whole forming one continued submarine rope, which, if not perfect in its mechanical arrangement, is nevertheless one which holds out high prospects of ultimate success. The core or conductor is, of course, of the same thickness and formation throughout from end to end, being formed of seven No. 18 copper wires, in all about one-eighth of an inch diameter the thickest conductor that has ever yet been made. The copper strands of this, in accordance with the advice of the electricians, have been very care- fully selected and tested for conducting power, as even the purest copper wire, from some unknown cause, has been found to vary in electrical con- ducting power as much as forty per cent. Its power of conducting heat also diminishes or increases in the same proportion with its electrical sensitive- ness. Yet, though the conductor with its insulating medium of gutta-percha is alike in diameter throughout, the manner in which this core is protected, or, we had better say, the thickness to which the outer covering is laid on, differs considerably. Thus, each of the two shore ends is made to rest in from 100 to 200 fathoms, and these for thirty knots each way are very massive, at the rate in weight of seven tons to the mile. The next length at each end is also of thirty knots, and will rest in from 200 to 400 fathoms water, and is for this depth a very massive cable, weighing about five tons to the mile. By the substitution of a finer gauge of wire at each two or three miles or so, this gradually tapers down to meet the first deep-sea length, which will be laid in from 500 to 800, or, possibly, even 1,000 fathoms. The length of this portion of the cable is 940 nautical miles, its weight in air two tons per mile, in water about thirty-four hundredweight. The deepest deep-sea portion across the centre of the Bay of Biscay extends over about 280 knots, though 300 knots are being manufactured to meet contin- gencies in submerging. Here the depth averages about 2,500 fathoms, equal to the very deepest parts of the cable plateau of the North Atlantic. To overcome the difficulties of this vast depth of water, the cable is strengthened by the introduction of steel wire in its outer covering, and reduced to weigh in air only twenty-six hundredweight; in water as low as thirteen. The weight of the Atlantic cable in air was one ton, and in water about fifteen or sixteen hundredweight, per mile. The different weights of the different parts of the cable are, of course, entirely due to the thickness of the outer spiral wires with which it is covered. The conductor, with its threefold insulation of gutta-percha, is all served round alike with yarns of tarred hemp closely bound in, and over which come the outer wires of various gauges: No. 1 gauge, the thickest known, being as thick as a cedar pencil, and so on up to No. 45 gauge, as fine as cotton. The two heaviest shore ends, then, of thirty miles each, are covered with twelve No. 3 gauge wires, which brings its weight up to seven tons a mile, and its breaking strain from twenty-five to thirty tons. The second land ends are enclosed in twelve No. 5 gauge wires, of five tons to the mile, and equal to about fifteen tons' strain. NATURAL PHILOSOPHY. 129 The first deep-sea length, of about nine hundred and fifty miles, for from five to eight hundred fathoms, is covered, like the Atlantic cable, with eighteen No. 11 gauge solid iron wires, weighing two tons the mile in air, thirty-three hundredweight in water, and equal to a strain of nearly eight tons. The deepest sea part is enclosed in twelve steel wires of No. 14 gauge, each wire being spun round and enclosed in a separate strand of hemp, in order, if possible, to take off that dangerous springiness and tendency to kink which makes all steel-wire rope, even when coiled, so lively, and so much resembling a cargo of live eels. The cable, the chief points of which we have thus described, is necessarily a most expensive one; for, as we have already stated, the government have contracted that all parts of the material and workmanship should be of the finest possible kind. Nevertheless, in spite of all the care that has been taken to secure a good rope, and the improvement which, with regard to strength with a certain amount of lightness, the deep-sea portion of this cable undoubtedly displays, it is still, we are sorry to say, constructed on the old self-destructive principle of spiral iron wires round a soft core, one of the most faulty mechanical arrangements that could have been attempted. There is not a single engi- neer of eminence who does not condemn the principle of laying on the out- side wires spirally, instead of longitudinally, in a line with the strain they have to resist. Why the old arrangement is persisted in at the present day it is difficult to imagine, unless it is due to the fact that most of the wire- rope manufacturers have their machines constructed for laying on the wires spirally, and do not care to make others which will render the completion of their work slower, more difficult, and less profitable. Four years ago, when the plan of construction of the Atlantic cable was resolved on, we most strongly deprecated this arrangement-, and the event has so clearly justified what we then pointed out would be the consequences, that we may be excused for quoting the opinion on the present occasion: " Whenever a cable is constructed with spiral wires round a soft core, any severe strain in paying it out must, by stretching the outside wires, either attenuate or break the insulation of the copper conductor. This is a simple fact, which those least conversant with mechanics can easily understand. We do not mean to say that the Atlantic cable cannot succeed, but the chances are very much against it; and it is certain that before it has been down twelve months it will, like most others similarly constructed, be per- fectly useless. If it does answer even temporarily, it will not be due to the plan on which it is made, but in spite of it." We shall, on another occasion, inform our readers of the chief principles on. which the light cable before mentioned is being constructed, and the prospects which cables of that description hold out of being successful when laid. All that we have at present to add with regard to the Gibraltar cable is, that the contractors undertake to submerge it at their own risk and expense; and to insure proper fulfilment of this portion of their task, the government very wisely retain five per cent of the price of the whole cable (which is nearly 300,000) in their own hands, and further compel Messrs. Glass and Elliot to give security to the amount of 20,000 that the rope shall be suc- cessfully laid. It is proposed to submerge it in two equal portions one from Gibraltar to Cape Finisterre, and one from Finisterre to (we hope) the southwest coast of Ireland. It is anticipated that the whole rope will be laid early in 1801. London Times. 130 ANNUAL OF SCIENTIFIC DISCOVERY. IMPROVEMENTS IX TELEGRAPHIC APPARATUS. Several improvements in the operation of the Morse telegraph have re- cently been completed in England. One by the brothers Disney marks the characters with ink, instead of simple indentation in the paper. This is a relief to the eyes of the operator, and an additional guaranty of accuracy. This is accomplished by making immovable the instrument for tracing, which, is a simple desk turning upon itself; the lever, moved by electricity, has no other function than to press the paper against the desk at divers intervals and for different lengths of time. By a clockwork movement this little desk rubs constantly against an clastic roller saturated with a fat ink, which long preserves its fluidity, so that it suffices to put a few drops of it every two or three days on the surface of the roller. This improvement has been adopted on the lines in France and Belgium. Mr. Wheatstone, of England, has also invented a convenient process for increasing the speed of transmission by the Morse instrument, similar to a process for the same purpose connected with the Bain instrument. A prepared paper is punched with holes corres- ponding to the Morse characters, and the message thus prepared is placed on a moving metallic band, and is made to take the place of aii operator and transmit itself. L. Bradley, of New York, has patented an improvement in telegraphing by sound, by which he dispenses with the local batteries of the House system. The magnet and armature are placed in the main circuit, and by a simple combination of sounding-board and overstrung wires the indistinct tick is expanded to a clear, sharp, and perfectly intelligible knock, which the ope- rator can follow with perfect ease and certainty. Each knock is loud and abrupt, and there is not the slightest liability of running them together, however rapid the manipulations of the operator. MAGNETISM AND THE MOOX. At the American Association, 18GO, Professor Bache presented a paper on the attempt, from observations at Girard College, to determine the effect of the moon upon the daily movements of the magnetic needle. The observa- tions and calculations of European magnetic observers have shown that such an effect is produced. The Philadelphia observations were divided into three groups, and the curves of each group were found to agree with each other, and with the results of General Sabine and others. Fourteen minutes after the moon is on the meridian, the needle is eighteen-hundredths of a minute westerly of its position, and six minutes after the moon passes the lower meridian, twenty-three hundredths of a minute west; while about moon-rise and moon-set the needle is nearly as much east of its position. There is also a slight single movement between two successive culminations of the moon, just as there is a daily, as well as a semi-daily, lunar tide in the ocean. Further examinations show a greater effect of the moon in summer than in winter. Moreover, it appears that the effect is probably greater at new moon than at full, and greater when the moon is north of the equator than when south. The effect when the moon is near the earth is greater than when she is at a greater distance. But it must be remembered that all these effects are exceedingly small. NATURAL PHILOSOPHY. 131 ON FIXING MAGNETIC PHANTOMS. The name "phantom" was given by M. de Haltlatto the figures which are obtained when iron-filings are thrown upon a sheet of paper or a pane of glass placed over a magnet. This physicist fixed these images by producing them upon a sheet of paper coated with starch or prepared with gelatine. This process certainly enables us to obtain the general form of the phan- toms; but all physicists can see that it suppresses the details. I therefore pro- pose another method, which is very simple, and succeeds perfectly. The paper upon which the phantoms are to be fixed is " waxed" paper. A sheet of this is placed over the poles of the magnet in question, and kept in a hori- zontal position by means of a screen placed between the paper and the mag- net. Then, proceeding in the usual manner, when the image is fully devel- oped, a hot brick is held above it, or the warm lid of a crucible, which is preferable, because it is lighter and easily managed with the tongs. They must not touch the paper, but only be brought within the distance necessary to fuse the wax. As soon as this happens, which is easily perceived by the glistening appearance produced, the brick is withdrawn. Meanwhile the current does not cease its activity, nor the filings lose their arrangement, in which position the whole solidifies so well that the fixed image does not at all differ from the phantom of the magnet in activity. Permanence is thus given to the sort of molecular arrangement which the filings take when ex- posed to magnetic influence. Instruction can hardly fail to be derived from the use of these means, by aid of which it will be possible to study the fig- ures more advantageously, which are, in some sense, the visible expression of the force animating bodies endowed with polarity developed by mag- netism. Professor J. Nickles, Silliman's Journal. ELECTRIC AND CALORIFIC CONDUCTION OF METALS. Messrs. Calvert and Johnson, after mimerous experiments, have arrived at the conclusion that the electric and calorific conduction powers of conduct- ing heat and electricity are proportional to each other in alloys as well as in simple metals; and that these powers are exhibited by the alloys of cop- per and zinc in a degree which differs little from that of zinc, whatever amount of copper they may contain. The rapidity with which the conduction of copper is reduced is very remarkable. Thus pure copper conducts electricity with a facility represented by the figures 73.6, and heat with one represented by 79.3; but when eight parts of copper are alloyed with one part of zinc, the conductibility for electricity is reduced to 27.3, and for heat to 25.5; that of zinc alone being for the former 28.1, and for the latter 27.3. The con- ductibility of alloys of tin and bismuth is nearly the mean of that of the component metals. ON THE CONSERVATION OF FORCE. Professor Faraday, in a recently published volume, entitled " Experimen- tal Researches in Chemistry and Physics," adds to his former expressed opinions, in relation to the conservation of force, 1 the following additional remarks : 1 See Annual of Scientific Discovery for 1858, pp. 177-189. Io2 ANNUAL OF SCIENTIFIC DISCOVERY. Since the first publication of certain opinions respecting gravitation, etc., I have come to the knowledge of various observations upon them, some ii> I verse, others favorable: these have given me no reason to change my own mode of viewing the subject; but some of them make me think that I have not stated the matter with sufficient precision. The word " force" is under- stood by many to mean simply " the tendency of a body to pass from one place to another," which is equivalent, I suppose, to the phrase "mechanical force." Those who so restrain its meaning must have found my argument very obscure. What I mean by the word " force," is the cause of a physical action; the source or sources of all possible changes amongst the particles or materials of the universe. It seems to me that the idea of the conservation of force is absolutely in- dependent of any notion we may form of the nature of force or its varieties, and is as sure, and may be as firmly held in the mind, as if we, instead of being very ignorant, understood perfectly every point about the cause of force and the varied effects it can produce. There may be perfectly distinct and separate causes of what are called chemical actions, or electrical actions, or gravitating actions, constituting so many forces; but if the " conservation of force" is a good and true principle, each of these forces must be subject to it: none can vary in its absolute amount; each must be definite at all times, whether for a particle, or for all the particles in the universe; and the sum also of the three forces must be equally unchangeable. Or, there may be but one cause for these three sets of actions, and in place of three forces we may really have but one, convertible in its manifestations; then the pro- portions between one set of actions and another, as the chemical and the elec- trical, may become very variable, so as to be utterly inconsistent with the idea of the conservation of two separate forces, the electrical and the chemical, but perfectly consistent with the conservation of a force being the com- mon cause of two or more sets of action. It is perfectly true that we cannot always trace a force by its actions, though we admit its conservation. Oxygen and hydrogen may remain mixed for years without showing any signs of chemical activity; they may be made at any given instant to exhibit active results, and then assume a new state, in which again they appear as passive bodies. Now, though we cannot clearly explain what the chemical force is doing, that is to say, what are its effects during the three periods before, at, and after the active combi- nation, and only by very vague assumption can approach to a feeble concep- tion of its respective states, yet we do not suppose the creation of a new portion of force for the active moment of time, or the less believe that the forces belonging to the oxygen and hydrogen exist unchanged in their amount at all these periods, though varying in their results. A part may at the active moment be thrown off as mechanical force, a part as radiant force, a part disposed of we know not how; but believing, by the principle of con- servation, that it is not increased or destroyed, our thoughts are directed to search out what, at all and every period, it is doing, and how it is to be recog- nized and measured. A problem, founded on the physical truth of nature, is stated, and, being stated, is on the way to its solution. Those who admit the possibility of the common origin of all physical force, and also acknowledge the principle of conservation, apply that princi- ple to the sum total of the force. Though the amount of mechanical force (using habitual language for convenience' sake) may remain unchanged and definite iu its character lor a long time, yet when, as in the collision of NATURAL PHILOSOPHY. 133 two equal inelastic bodies, it appears to be lost, they find it in the form of heat; and whether they admit that heat to be a continual mechanical action, as is most probable, or assume some other idea, as that of electricity, or action of a heat-fluid, still they hold to the principle of conservation, by ad- mitting that the sum of force, that is, of the " cause of action," is the same whatever character the effects assume. With them the convertibility of heat, electricity, magnetism, chemical action, and motion, is a familiar thought; neither can I perceive any reason why they should be led to exclude, a priori, the cause of gravitation from association with the cause of these other phe- nomena respectiA'ely. All that they are limited by in their various investi- gations, whatever directions they may take, is the necessity of making no assumption directly contradictory of the conservation of force applied to the sum of all the forces concerned, and to endeavor to discover the different directions in which the various parts of the total force have been exerted. Those who admit separate forces inter-unchangeable, have to show that each of these forces is separately subject to the principle of conservation. If gravitation be such a separate force, and yet its power in the action of two particles be supposed to be diminished fourfold, by doubling the distance, surely some new action, having true gravitation character, and that alone, ought to appear; for how else can the totality of the force remain unchanged? To define the force " as a simple attractive force exerted between any two or all the particles of matter, with a strength varying inversely as the square of the distance," is not to answer the question; nor does it indicate, or even assume, what are the other complementary results which occur, or allow the supposition that such are necessary : it is simply, as it appears to me, to deny the conservation of force. As to the gravitating force, I do not" presume to say that I have the least idea of what occurs in two particles when their power of mutually approach- ing each other is changed by their being placed at different distances; but I have a strong conviction, through the influence on my mind of the doctrine of conservation, that there is a change; and that the phenomena resulting from the change will probably appear some day as the result of careful research. If it be said that "'twere to consider too curiously to consider so," then I must dissent : to refrain to consider would be to ignore the prin- ciple of the conservation of force, and to stop the inquiry which it suggests; whereas, to admit the proper logical force of Vhe principle in our hypoihescs and considerations, and to permit its guidance in a cautious yet courageous course of investigation, may give us power to enlarge the generalises wo already possess in respect of heat, mo' ion, electricity, magnetism, etc., to associate gravity with them, and, perhaps, enable us to know whether the essential force of gravitation (and other attractions) is internal or external, as respects the attracted bodies. Returning once more to the definition of the gravitating power as " a sim- ple attractive force exerted between any two or all the panicles or masses of master at every sensible distance, bnt with a strength varying inversely as the square of the distance," I ought, perhaps, to suppose there are many who accept this as a true and sufficient description of the force, and who, there- fore, in relation to it, deny the principle of conservation. If both are ac- cepted, and are thought to be consistent with each other, it cannot be difficult to add words which shall make "varying strength" and " conservation" a-iree together. It cannot be said that the definition merely applies to the effects of gravitation as far as we know them. So understood, it would form 12 134 ANNUAL OF SCIENTIFIC DISCOVERY. no barrier to progress; for that particles at different distances are urged, to- wards each other with a power varying inversely as the square of the dis- tance is a truth; but the definition has not that meaning; and what I object to is the pretence of knowledge which the definition sets up when it assumes to describe, not the partial effects of the force, but the nature of the force as a whole. THE CORRELATION AND HOMOGENESIS OF PHYSICAL FORCES. The following article, written by L'Abbe Moigno, was recently published in the London Photographic Neics: All the forces of nature motion, heat, light, electricity, magnetism, chemical affinity have intimate relations or correlations with each other. These forces engender each other; so that, one being given, AVC can, by put- ting it into action, produce all the others. This generation or homogenesis of the various forces by each other takes place in definite proportions, or according to the law of fixed equivalents; so that the quantity of any one of these forces expended in the act of generating another force is always represented by a corresponding quantity of the force engendered. Thus, for example, if, to create a mechanical force, we expend, without loss, the quantity of heat necessary to raise a kilogramme of water one degree of heat, the mechanical force produced will be capable of raising, in a second of time, 427 kilogrammes to the height of a meter; and reciprocally, if, to produce one degree of heat, we expend the force capable of raising a meter in height, in one second, a weight of 427 kilogrammes, the quantity of heat engendered will be that necessary to communicate, and will suffice to com- municate to a liter of water one degree of temperature. M. de Beaumont's machine admirably demonstrates this fundamental principle, which will receive its full development when science shall have become able to define and accurately determine the mechanical, thermal, photogenic, electric, mag- netic, and synergic equivalents as clearly and accurately as it has arrived at determining the chemical equivalents of various simple and compound substances. But this is not all. In making another step in advance, we have estab- lished, as a certain proposition, that the generation or homogenesis of the various forces of nature is accomplished by a real transformation of one into another; so that, for example, heat, under given conditions, is trans- formed into a motive power, into light, electricity, magnetism, and chemical affinity; or, rather, becomes motive power, light, electricity, magnetism, and chemical affinity. The beautiful experiment of Faraday, completed and fully developed by Foucault, of a cube submitted to rapid motion becoming hot when this motion suddenly stopped, is the sufficient and certain demon- stration of the transformation of the quantity of motion into the quantity of heat a transformation regulated by the principle of equivalents. At length we arrive at the theory or metaphysical reason of these intimate relations of the homogenesis, of these mutual generations or transmissions, always obeying the laws of equivalents. Our profound conviction is, that Mr. Grove and M. Scguin arc perfectly correct when they assert that in nature there are only two things, matter and motion; matter under two forms, and submitted to the law of universal attraction; motion once im- pressed on matter, which cannot augment either in. its quantity or in the sum of its active forces, which may be successively transformed and modified. NATURAL PHILOSOPHY. 135 When a ray of light falls upon- a daguerreotype plate, forming part of a galvanic circuit, which includes a galvanometer and Breguet's metallic ther- mometer, there is instantaneously and simultaneously produced chemical affinity on the surface of the plate, an electric current in the galvanometer, an elevation of temperature in the thermometer, motion in the two needles of the galvanometer and thermometer, etc. As a concrete and striking example of homogenesis, we may instance what we will term the human machine, that masterpiece of creative power. It is sustained solely, first by alimentary provision, composed of carbon, hydrogen, nitrogen, and assimi- lative mineral principles, then by atmospheric air introduced by respiration. The vital phenomenon, par excellence, is the combustion of carbon and hydrogen by the oxygen of the atmosphere a combustion which, it ap- pears to us, is summed up in a first disengagement, in a first motion, in a first circulation. Now, observe to what this first motion gives birth: a very intense heat, which maintains our whole body, even in winter, at a temper- ature of ninety-eight degrees Fahrenheit; an electric or nervous current, of which M. Helmholtz has established the existence and measured the velocity; the circulation of the blood in the entire system of arteries and veins; a mechanical force sufficient to transport the entire body which, upon an average, weighs 100 pounds, with a velocity of several yards per second; the muscular force exercised by the various organs, which make of an active man one of the strongest animals in creation; chemical affinity, under a thousand different forms, with the very complex series of combinations and decompositions, assimilations and secretions, etc. : evidently, this is not only the correlation of physical forces, it is also their homogenesis, their mutual transformation, their identity in cause and also in nature, etc. NEW COSMICAL FORCE. Jacobi, of St. Petersburg, well known to the scientific world for his fine researches on light and magnetism, has recently thrown out some remark- able ideas on the necessity of introducing into calculations of the planetary system a new force, besides gravitation, namely, induction. The numerous practical applications of the remarkable force, electro-magnetism, he says, have rather pushed out of sight the vast importance of the discovery in a purely scientific point of view, and observes that he has no scruple in placing it by the side of gravitation as a force in celestial mechanics Here are a few of the most intelligible links in his chain of reasoning: All bodies are magnetic to a greater or less degree; the earth is a vast magnet, and it is doubtless the same with other planets and their satellites, and even with the sun himself. Now it is a general law, and also a fact proved by every- day experience, that when two bodies, both permeated by magnetic currents, approach or recede from each other, their approach or their recession gene- rates contrary currents of induction. And it is these currents of induction, with their consecutive and perturbative attractions or repulsions, that he proposes to introduce into the explanation of the phenomena of celestial mechanics. INFLUENCE OF LIGHT IN GRAVITATION. The following is an abstract of an essay on the above subject, by Dr. Wm. S. Green, of Muscogee County, Georgia : 1. It is argued that gravitation is an action of contiguous atoms of matter, 130 ANNUAL OF SCIENTIFIC DISCOVERY. impressible by liizht. 2. That the velocity of motion of these atoms toward each other is a measure of the force of gravity. 3. That the velocity of the00 = 1.000 " 24 00 00 Mars, %/.12535 = .707 " 33 54 28 Jupiter, . 7 7232 = 2.546 " 9 23 00 Saturn, 6 \/ib3.4S990 = 2.169 " 11 07 00 Uranus, \A.4994Q = 1.270 " 18 45 00 Neptune, G ^2^2liTl = 1.147 " 20 56 32 GROWTH OF A CRYSTAL. Mr. Xevil Story Maskelyne, in a paper read by him to the Royal Institution, " On the Insight hitherto obtained into the nature of the Crystal Molecule by the instrumentality of Light," in conclusion, says: In every case the growth of a crystal is an inexplicable thing, so long as we endeavor to trace its cause to powers residing in, and confined to, the 12* ANNUAL OF SCIENTIFIC DISCOVERT. molecule-. A cry-tal, like a plant, H developed in a medium; and as the plant ouo the -pi-rial peculiarities of its individual form, notwithstanding the seeminirlv perfect freedom of its growth, to special circumstances in the -oil, the air, the weather, during that growth; and its general similarity to other plants of its kind, to the organic laws that control the conditions of its species; so must the crystal be considered as the result of many cooperating influences, including those of the foreign constituents of the mother liquid, those of temperature and other physical conditions, and involving the prin- ciple that the molecules, whether those deposited, or those about to become so, affect or are affected by and that to considerable distances the whole tne mean velocity being about 1,50-3 feet per second; and therefore each particle makes 8,077,200,000 collisions per second.. 4. The laws of the diffusion of gases, as established by Professor Graham, Jr., are deduced from this theory, and the absolute rate of diffusion through an opening can be calculated. The author intends to apply his mathematical methods to the explanation on this hypothesis of the propagation of sound, and expects some light on the mysterious question of the absolute number of such particles in a given mass. COLOR-BLIXDNESS. If there is one infirmity or defect of those five senses with which we are mo.st of us blest which more than any other attracts sympathy and claims compassionate consideration, it is blindness, an inability to know what is beautiful in form or in color, to appreciate light, or to recognize and compre- hend the varying features of our fellow-men, a perpetual darkness in the midst of a world of light, a total exclusion from the readiest, pleasantest, and most available means of acquiring ideas. And yet who would suppose that there exists, and is tolerably common, a partial blindness, which has hardly been described as a defect for more than half a century, and of which it may be said, even now, that most of those who suffer from it are not only themselves ignorant of the fact, but those about them can hardly be induced to believe it. The unhappy victims of this par- tial blindness (which is real and physical, not moral) are at great pains in learning what to them are minute distinctions of tint, although tp the rest of the world they are differences of color of the most marked kind, and, after all, they only obtain the credit of unusual stupidity or careless inattention, in reward for their exertions and in sympathy for their visual defect. We allude to a peculiarity of vision which first attracted notice in the case of the celebrated propoundcr of the atomic theory in chemistry, the late Dr. Dalton, of Manchester, Avho, on endeavoring to find some object to compare in color with his scarlet robe of doctor of laws, when at Cambridge, could hit on nothing which better agreed with it than the foliage of the adjacent trees, and who, to match his drab coat, for our learned doctor was of the Society of Friends, might possibly have selected crimson continuations, as the quietest and nearest match the pattern-book of his tailor exhibited. An explanation of this curious defect will be worth listening to, the more so as one of our most eminent philosophers, Sir John Herschel, has recently made a few remarks on the subject, directing attention at the same time to other little known but not unimportant phenomena of color, which bear upon and help to explain it. It is known that white light consists of the admixture of colored rays in certain proportions, and that the beautiful prismatic colors seen in the rain- bow are produced by the different degree in which the various rays of color are bent when passing from one transparent substance into another of different density. Thus, when a small group of color-rays, forming a single pencil or beam of white sunlight, passes into and through the atmosphere during a partial shower, and falls on a drop of rain, it is first bent aside on entering the drop, then reflected from the inside surface at the back of the drop, and ultimately emerges 4n an opposite direction to its original one. During these changes, however, although all the color-rays forming the 140 ANNUAL OF SCIENTIFIC DISCOVERY. white pencil have been bent, cadi ha.s been bent at a different angle, the ml most, and the blue least. When, therefore, they come out of the drop, tin- ifl rays are quite separated from the blue, and when the beam reaches ir> destination, the various colors enter the eye separately, forming a line of variouslv colored light, the upper part red and the lower part blue, instead t>i a mere point of white light, as the ray would have appeared if seen before it entered the drop. The eye naturally refers each part of the ray to the place from whence it appears to come, and thus, with a number of drops falling and the sun not obscured, a rainbow is seen, which represents part of a number of concentric circular lines of color, the outermost of which is red, the innermost violet, and the intermediate ones we respectively name orange, yellow, green, blue, and indigo. It has also been found, by careful experiment, that these are not all pure colors, most of them being mixtures of some few that are really primitive and pure, and necessarily belong to solar light. It is these, mixed in due proportion, which make up ordinary white light, which is the only kind seen when the sun's rays have not undergone this sort of decomposition, or sepa- ration into elements. The actual primitive colors are generally supposed to be red, yellow, and blue, and much theoretical as well as practical discussion has arisen as to how these require to be mixed, what proportion they bear to each other in their power of impressing the human eye, and many other matters, for which we must refer to Mr. Field, Mr. Owen Jones, and others, who have studied the subject and applied it. In a general way it is found convenient to remember, or rather to assume, that three parts of red, five parts of yellow, and eight parts of blue, form together white, and, therefore, that the pencil of white light contains three rays of red, five of yellow, and eight of blue. To produce the other prismatic colors, we must mix red with a little yellow to form orange; yellow with some blue to form green; much blue with a little red to form indigo, and a little blue with some red to form violet. In performing experiments on color it is convenient, instead of a drop of water, to substitute a prism of glass in decomposing the rays of light. We may thus produce at will a convenient image, called a prismatic spectrum, which, when thrown on a wall, is a broad band of colored lights, having all the tints of the rainbow in the same order. Looking at this image, the red is at the top and the violet at the bottom, and it may be asked, How does the red get amongst the blue to form violet, if the red rays are bent up to the top of the spectrum? The answer is, that a quantity of white light not decomposed, and a part of all the color-rays, reach all parts of the spectrum, however carefully it is sheltered, but that so many more red rays get to the top, so many more of the yellow to the middle, and so many more blue to where that color appears most brilliant, that these are seen nearly pure, whilst where the red and yellow or yellow and blue mix they produce distinct kinds of color, and where the blue at the bottom is faint, and some of those red rays fall that do not reach the red part of the spectrum, the violet is produced. In point of fact, therefore, all the colors of the spectrum, as seen, are mixtures of pure colors with white ILht, while all but red are mixtures of other pure colors with some red and some yellow, as well as white. Primitive and pure colors, therefore, are not obtained in the spectrum, and a question has arisen as to which really de- serve to be called pure; Dr. Young upholding green against yellow, and even regarding violet as primitive, and blue a mixed color. A consideration of NATURAL PHILOSOPHY. 141 the results of this theory would lead us further than is necessary for the purpose we have now in view. We also find philosophers now-a-days calmly discussing a question which most people considered settled very long ago, namely, whether blue and yellow together really make green. It is of no use for the artist to lift up his eyes with astonishment at any one being so insane as to question so generally admitted a statement. In vain does he point to his pictures, in which his greens have been actually so pro- duced. The strict photologist at once puts him down, by informing him that he knows little or nothing of the real state of the case : his (the artist's) col- ors are negative, or hues of more or less complete darkness ; whereas in nature the color question is to be decided by positive colors, or hues in which all the light used is of one kind. The meaning of this will be best understood by an example: When a ray of white light falls on a green leaf, part of the ray is absorbed and part reflected, and the object is therefore only seen with the part that is reflected. That which is absorbed consists of some of each of the color-rays, and the resulting reflected light is nothing more than a mixture of what remains after this partial absorption. The green we see consists of the original white light deprived of a portion of its rays. It is not a pure and absolute green, but only a residual group of colored rays, and thus in so far the green color is negative, or consists of rays not absorbed. It is therefore partial darkness, and not absolute light. If, however, on the other hand, a ray of white light is passed through a transparent medium (e. y., some chemical sal;) which has the property of entirely absorbing all but one or more of the color-rays, and no part of the remainder, then all the light that passes through this medium is of the one color, or a mixture of the several colors that pass; and if such" light is thrown on a white ground, the reflected color will be positive, and not negative, and is far purer as well as brighter than the color obtained in the other way. It has been found by actual experiment that when positive blue, thus obtained, is thrown on positive yellow, the resulting reflected color bears no resemblance to gi-een. Sir John Herschel considers that whether green is a primitive color in other words, whether we really have three or four primitive colors remains yet an open question. It was necessary to explain these matters about color before directly referring to the subject of this paper, namely, blindness to certain color-rays. It should also be clearly understood that the persons subject to this peculiar condition of vision have not, necessarily, any mechanical or optical defect in the eye, as an optical instrument, which may be strong or weak, long-sighted or short-sighted, quite independently of it. Color-blindness does not in any way interfere with the ordinary requirements of vision, nor is there the smallest reason to imagine that it can get worse by neglect, or admit of any improvement by education or treatment. Assuming that persons of ordinary vision see three simple colors, red, yellow, and blue, and that all the rest of the colors are mixtures of these with each other and with white light, let us try to picture to ourselves what must be the visual condition of a person who is unable to recognize certain rays; and as it appears that there is but one kind of color-blindness known, we will assume that the person is unable to recognize those rays of white light which consist of pure red and nothing else. In other words, let us invest igate the sensations of a person blind so far only as pure red is concerned. 1 | L > ANM AL OF SCIKNTIFIC DISCOVKKY. All visible objects ei her reflect th; 1 same kind of li^ht as that which falls on them. ;il>-.r1.iii- I"""' and reflecting the rest, or else they absorb more of i,,iiie color-rays than others, and reflecl only a negative tint, made up of a mixture <>f all the color-rays not absorbed. To a color-blind person, the mixed li^ht, as it proceeds from the sun, is probably white, as seen by those havinir perfect vision; for, as we have explained already, positive blue and yellow (the color-rays when red is excluded) do not make green, and the absence of the red ray is likely to produce only a slight darkening effect. So far, then, there is no difference. But how must it be with regard to color? Hearing in mind what has been said above, it is evident that in withdrawing the red rays from the spectrum, we affect all the colors. The orange is no longer red and yellow, but darkened yellow; the yellow is purer, the green is quite distinct, the bine purer, and the indigo and violet no longer red and blue, but blue mingled with more or less of darkness, the violet being the darkest, as containing least blue in proportion to red, while the red part itself, though not seen as a color, is not absolutely black, inasmuch as its part of the spectrum is faintly colored with the few mixed rays of blue and yellow an. 1 white that escape from their proper place. The red then ought to be seen as a gray neutral tint, the orange a dingy yellow, the indigo a dirty indigo, and the violet a sickly, disagreeable tint of pale blue, darkened con- siderably with black and gray. Next, let us take the case of an intelligent person affected with color-blind- ness, but who is not yet aware of the fact. He has been taught from child- hood that certain shades, some darker and some brighter, but all of neutral tint, and not really presenting to him color at all, are to be called by various names, scarlet, crimson, pale red, dark red, bright red, dark green, dark purple, brown, and others. With all these lie can only associate an idea of gray; nor can he possibly know that any one else sees more than he does. Having been taught the names they are called by, he remembers the names, with more or less accuracy, and thus passes muster. There is a real differ- ence of tint, because each of these colors consists of more or less blue, yellow, and white, mixed with the red; and our friend is enabled to recog- nize and name them, more or less correctly, according to his aeuteness of perception and accuracy of memory. If we desire to experiment on such a person, we must ask no names what- ever, but simply place before him a number of similar objects differently colored. Taking, for example, skeins of colored wools, let us select a com- plete series of shades of tint, from red, through yellow and green to violet, and request him to arrange them as Avell as he is able, placing the darkest shades first, and putting those tints together that are most like each other. It is curious then to watch the progress of the arrangement. In a case lately tried by the writer of this article, the color-blind person first threw a-idc at once a particular shade of pale green as undoubted white, and then several dark blues, dark reds, dark greens, and browns, were put together a~ black. The yellows and pure blues were placed correctly, as far as name was concerned, by arranging several shades in order of brightness, but the order was very different from that which another person would have The greens were grouped, some with yellows, and some with blues. I h.- colors in this experiment were all negative and impure; but we may ) obtain something like the same result with positive color, transmitted .1 of polarized light through plates of mica. In a case of this kind ascribed by Sir J. Ilerschel, the only colors seen were blue and yellow, NATURAL PHILOSOPHY. 143 while pale pinks and greens were regarded as cloudy white, fine pink as very pale blue, and crimson as blue; white red, ruddy pink, and brick red were all yellows, and fine pink blue, with much yellow. Dark shades of red, blue, or brown were considered as merely dark, no color being recog- nized. The account of Dr. Dalton's own peculiarity of vision, by himself, offers considerable interest. He says, speaking of flowers : " With respect to colors that were white, yellow, or green, I readily assented to the appropriate term; blue, purple, pink, and crimson appeared rather less distinguishable, being, according to my idea, all referable to blue. I have often seriously asked a person whether a flower was blue or pink, but was generally con- sidered to be in jest." He goes on further to say, as the result of his experience: "1st. In the solar spectrum three colors appear, yellow, blue, and purple. The two former make a contrast; the two latter seem to differ more in degree than in kind. 2d. Pink appears by daylight to be sky-blue a little faded; by candle-light it assumes an orange or yellowish appearance, which forms a strong contrast to blue. 3d. Crimson appears muddy blue by day, and crimson woollen yarn is much the same as dark blue. 4th. lied and scarlet have a more vivid and flaming appearance by candle-light than by daylight" (owing, probably, to the quantity of yellow light thrown upon, them). As anecdotes concerning this curious defect of color-vision, we may quote also the following: "All crimsons appear to me (Dr. Dalton) to be chiefly of dark blue, but many of them have a strong tinge of dark brown. I have seen specimens of crimson claret and mud which were very nearly alike. Crimson has a gra-ve appearance, being the reverse of every showy or splendid color." Again: "The color of a florid complexion appears to me that of a dull, opaque, blackish blue upon a white ground. Dilute black ink upon white paper gives a color much resembling that of a florid com- plexion. It has no resemblance to the color of blood." We have a detailed account of the case of a young Swiss who did not perceive any great differ- ence between the color of the leaf and that of the ripe fruit of the cherry, and who confounded the color of a sea-green paper with the scarlet of a riband placed close to it. The flower of the rose seemed to him greenish blue, and the ash-gray color of quicklime light green. On a very careful comparison of polarized light by the same individual, the blue, white, and yellow were seen correctly, but the purple, lilac, and brown were confounded with red and blue. There was in this case a remarkable difference noticed according to the nature and quantity of light employed; and as the lad seemed a remarkably favorable example of the defect, the following curious experiment was tried. A human head was painted, and shown to the color- blind person, the hair and eyebrows being white, the flesh brownish, the lips and cheeks green. When asked what he thought of this head, the reply was, that it appeared natural, but that the hair was covered with a nearly white cap, and the carnation of the cheeks was that of a person heated by a long walk. There is an interesting account in the Philosophical Transactions for 1859 (p. 32-5), which well illustrates the ideas entertained by persons in this con- dition with regard to their own state. The author, Mr. W. Pole, a well- known civil engineer, thus described his case : " I was about eight years old, when the mistaking of a piece of red cloth for a green leaf betrayed the existence of some peculiarity in my ideas of color; and as I grew older Ill ANN! AI. OF SCIKXTIF1C DISCOVERY. continue,! errors of a similar kind led my friends to suspect that my eyesight .left cti\e; '"'t l myself ronld not comprehend this, insisting that I saw rs clearly enough, and only mistook their names. "I was articled to a civil engineer, and had to go through many years' practice in making drawings of the kind connected with this profession. The>e arc frequently colored, and I recollect often being obliged to ask, in copying a drawing, what colors I ought to use; but these difficulties left no permanent impression, and up to a mature age I had no suspicion that my vision was different from that of other people. I frequently made mistakes, and noticed many circumstances in regard to colors which temporarily per- plexed me. I recollect, in particular, having wondered why the beautiful rose light of sunset on the Alps, which threw my friends into raptures, -eemed all a delusion to me. I still, however, adhered to my first opinion, that I was only at fault in regard to the names of colors, and not as to the, idea of them; and this opinion was strengthened by observing that the persons who were attempting to point out my mistakes often disputed among themselves as to what certain hues of color ought to be called." Mr. Pole adds that he was nearly thirty years of age when a glaring blunder obliged him to investigate his case closely, and led to the conclusion that he was really color-blind. All color-blind persons do not seem to make exactly the same mistakes, or see colors in the same way; and there are, no doubt, man} 7 minor defects in appreciating, remembering, or comparing colors which are sufficiently common, and which may be supcradded to the true defect, that of the optic being insensible to the stimulus of pure red light. It has been asserted by Dr. Wilson, the author of an elaborate work on the subject, that as large a proportion as one person in every eighteen is color-blind in some marked degree, and that one in every fifty-five confounds red with green. Certainly the number is large, for even* inquiry brings out several cases; but, as Sir John Herschel remarks, were the average anything like this, it seems incon- ceivable that the existence of the defect should not be one of vulgar noto- riety, or that it should strike almost all uneducated persons, when told of it, as something approaching to absurdity. He also remarks, that if one soldier out of every fifty-five were unable to distinguish a scarlet coat from green grass, the result would involve grave inconveniences, that must have attracted notice. Perhaps the fact that a difference of tint is recognixed, although the eye of the color-blind person docs not appreciate any differ- ence of color, when red, green, and other colors are compared together, and that every one is educated to call certain things by certain names, whether he understands the true meaning of the name or not, may help to explain both the slowness of the defective sight to discover its own peculiarity, and the unwillingness of the person of ordinary vision to admit that his neigh- bor really does not see as red what he agrees to call red. There is, however, another consideration that this curious subject leads to. It is known that out of every 10,000 rays issuing from the sun, and pene- trating spare at the calculated rate of 200,000 miles in each second of time, about one-tmh parr is altogether lost and absorbed in passing through the atmosphere, and never reaches the outer envelop of the human eye. It is iiown that of the rays that proceed from the sun, some produce light, some heat, and some a peculiar kind of chemical action to which the mar- s of photography an> due. Of these, only the light rays are appreciated specially by Hie eye, aliliough liie others are certainly quite as important in NATURAL PHILOSOPHY. 145 preserving life and carrying on the business of the world. Who can tell whether, in addition to the rays of colored light that together form a beam of white light, four-fifths of which only pass through the atmosphere, there may not have emanated from the sun other rays altogether absorbed and lost; or whether, in entering the human eye, or being received on the retina at the back of the eye, or nuvdc sensible by the optic nerve, there may not Lave been losses and absorptions sufficient to shut out from us, who enjoy what we call perfect vision, some other sources of information? How, in a word, do we who see clearly only three or four colors, and their various combinations, together with their combined white light, how do we know that to beings otherwise organized, the heat or chemical rays, or others we are not aware of, may not give distinct optical impressions? We may meet one person whose sense of hearing is sufficiently acute to enable him to hear plainly the shrill night-cry of the bat, often totally inaudible, while his friend and daily companion cannot perhaps distinguish the noise of the grasshopper or the croaking of frogs, and yet neither of these differs suf- ficiently from the generality of mankind to attract attention, and both may pass through life without finding out their differences in organization, or knowing that the sense of hearing of either is peculiar. So undoubtedly it is with light. There may be some endowed with visual powers extraordi- narily acute, seeing clearly what is generally altogether invisible; and this may have reference to light generally, or to any of the various parts of which a complete sunbeam is composed. Such persons may habitually see what few others ever see, and yet be altogether unaware of their powers, as the rest of the world would be of their own deficiency. The case of the color-blind person is the converse. He sees, it is true, no green in the fields, or on the trees; no shade of pink mantling in the coun- tenance, no brilliant scarlet in the geranium flower; but still he talks of these things as if he saw them, and J\e believes he does see them, until by a long process of investigation he finds out that the idea he receives from them is very different from that received by his fellows. He often, however, lives on for years, and many have certainly lived out their lives, without guessing at their deficiency. These results of physical defects of certain kinds remaining totally un- known, either to the subject of them or his friends, even when all are edu- cated and intej^gent, are certainly very curious; but it will readily be seen that they are inevitable in the present development of our faculties. In almost everything, whether moral or intellectual, we measure our fellows by our own standard. He whose faculties are powerful, and whose intellect is clear, looks over the cloud that hovers over lower natures, and wonders why they, too, will not see truth and right as he sees them. Those, on the other hand, who dwell below, among the mists of error and the trammels of pre- judice, will not believe that their neighbor, intellectually loftier, sees clearly over the fog and malaria of their daily atmosphere. In taking leave of the question of color-blindness, it should be mentioned that hitherto no case has been recorded in which this defect extends to any other ray than the red. There seems no reason for this, and possibly, if they were looked for, cases might be found in which the insensibility of the optic nerve had reference to the blue instead of the red ray, the least, instead of the most, refrangible part of the beam of light. It would also be well worth the trial if those who have any reason to suppose that they enjoy a superiority of vision would determine by actual experiment the extent of their unusual 13 146 ANNUAL OF SCIENTIFIC DISCOVERY. power?, and learn whether they refer to an optical appreciation of the chemi- or heal rays, or show any modification of the solar spectrum by enlarge- ment or otherwise. Lastly, it would be well, when children show an unusual difficulty in de- scribing colors, to try, by some such experiments as those here related, whether any detect of color-blindness exists or not. It would clearly be undesirable that such children as have this detect should waste time in learning accom- plishments or professions which they must always be unable to practise. They, their parents, and teachers may thus be saved some of that disappointment which is always experienced when presumed tastes and talents are cultivated or forced contrary to the natural powers of the individual. It must clearly be hopeless to endeavor to obtain good taste in colors, when most of the colors themselves are not seen at all, or are so recognized as to present appearances altogether different from those seen by the rest of the world. THE CHAMELEON'S CHANGE OF COLOR. In IS\H, the celebrated Dutch anatomist,' Vrolik, ascertained the fact of the influence exercised by light on the color of these animals ; and he observed also that there was a constant succession, or oscillation, of colors. Four years later, his countryman, Tan der Hooven, executed the plan of repro- ducing in five different plates the changes of color he observed. These show that the fundamental color of the animal persists under all the variations which may take place in parts. He observes that the median line, from the chin downwards, is always of one yellow tint. In his opinion the changes of color are due to a pigment underneath the skin. This idea was taken up by Milne-Edwards, who had two chameleons with different shades of color: the one presenting violet-spots on its flanks ; the other, green spots of varying shade. He observed that the change of color was quite independent of the animal's swelling himself out or not. On removing a strip of skin from the dead animal, and placing it under a microscope, he observed that the darkest color was beneath the tubercles, and that in these spots the yellow color was masked, but not replaced; it still existed, although the violet spots beneath it rendered it invisible. Two pigments therefore are possessed by the chameleon: one, the yellow pigment, being distributed over the surface; the other, the violet pigment, being distributed underneath tie former, and only becoming visible under certain circumstances, such as the stimulus of light. Milne-Edwards found that, on stimulating the yellow spots with alcohol or acids, they became violet ; on stimulating the violet spots they became yellow. And thus, after many centuries of easy fable and reiterated assumptions, the more arduous but more fruitful methods of exact science gained the key to the whole mystery. But only the key. Milne-Edwards had explained the and black hues, but had not explained the others. That was reserved for Prof. Bruecke, of Vienna. He has succeeded to the satisfaction of men of cience; but as it would require more technical knowledge to understand his explanation than can be expected of the ordinary reader, and would lead ns _:h beyond our limits, we will merely add", that his observations show the chameleon has his own colors, and does not borrow them from sur- rounding objects ; if he sometimes shows more of one than of another, it is that, like a ne-ro maiden blushing, the emotions of his soul are eloquent on his surface, but simply that the rays of li-ht act upon his skin. After NATURAL PHILOSOPHY. 147 which explanation, it is hoped that we shall hear no more scandals about this much abused Saurian. CHROMEIDOSCOPE. Under this name a new form of kaleidoscope has recently been brought out in England. The objects viewed, instead of being bits of colored glass, etc., are patches of floss silk of various colors, arranged on a spindle, capa- ble of being drawn in and out, and rotated, so as to make endless changes. The effect is very pretty, and, as any figure can be reproduced and kept sta- tionary, the instrument is likely to be of use to designers for manufactured goods, as well as forming a pleasing optical toy. THE DEBUSSCOPE. This name has been given to a recent French invention, which consists of two silvered plates, highly polished and of great reflective power, placed together in a frame-work of cardboard or wood, at an angle of seventy degrees. On being placed before a small picture, a design of any kind, no matter how rough, or whether good or bad, the debusscope will reflect the portion immediately under the eye, on all sides, forming the most beautiful designs ; and, by being slowly moved over the picture, will form new designs to any extent. The instrument gives the design in such a manner that it can be made stationary at pleasure, until copied. It is, therefore, an inex- haustible treasure to draughtsmen and others. Setting aside the utility of the debusscope altogether, it can be made the means of gratification in the drawing-room, and, doubtless, will soon assume its proper place along with the microscope and stereoscope, as a source of amusement. LOSS OF LIGHT BY GLASS SHADES. A correspondent (W. King) of the London Journal of Gas-lighting gives the following table, made up from a series of experiments, of the amount of light lost by various shades : Description of shade. Loss of light Clear glass, .... . 10.67 per cent. Ground glass (entire surface ground), . 29.48 Smooth opal, . . . 52.83 Ground opal, 55.85 Ground opal, ornamented with painted \ figures, the figures intervening between I 73.98 the burner and the photometer screen, ) As the large amount of light lost by the use of a clear glass shade excited some surprise, a sheet of common window glass was placed between the burner and the photometer screen, when it was found that 9.34 per cent of the light was intercepted, thus confirming the result obtained by the employment of a shade of clear glass. The shades were selected from a large number, and great pains taken to obtain an average specimen of each kind. The result of a series of comparative experiments on the same subject 148 ANNUAL OF SCIENTIFIC DISCOVERY. lias boon also communicated to Silliman's Journal, November, 1800, by Y. H. Stoirr, Esq., of Boston. Instead of lamp shades, however, flat sheets of jrlass (ordinary window-panes), six by eight inches, were fitted to a rack of blackened wire, which was fastened to a photometer bar (one hundred inrlK-s long), at a distance of three feet from the gas-light. The illuminat- ing power of the gas used was equal to sixteen candles, consuming, by cal- culation, one hundred and twenty grains of spermaceti per hour. The results obtained were as follows : I " -.1 TV i Description of glass. Thick English plate, Crystal plate, ... English crown, " Double English," window-glass, "Double German,"! " Single German," 1 Double German, ground, 2 Single German, ground, 2 Berkshire (Mass.), grouud,2 . Berkshire enamelled, i. e., ground \ only upon portions of its sur- /- T 5" face, small figure, \ " Orange-colored " window-glass, "Purple" " " " "Ruby" " " " "Green" " " " A porcelain transparency (Tyrolese Hunter), Thickness of glass. i of an inch, 3 tt 1C Loss of light. 6.15 per cent. 8.61 " 13.08 " 9.39 13.00 4.27 62.34 65.75 62.74 51.23 1C & 34.48 A As used for 85.11 o church win- rV dows, etc. rV 81.97 97.68 " The term ' loss of light/ " says Mr. Storer, " does not at first seem to be strictly appropriate, for a very considerable portion of the light not trans- mitted by a glass shade might be reflected against the walls of the apart- ment in which the lamp is burning, and thus aid in the general illumination of the room. The meaning of the expression is, however, perfectly evident; and there can be no doubt that the numbers given express as accurately as the circumstances of the case admit the actual diminution in the amount of light falling, for example, upon the pages of a book held near its source, which would be occasioned by the interposition of the shades enumerated in the tables." In commenting upon this subject, the editor of Silliman's Journal further remarks : 1 Among the Boston dealers, the term German is applied to glasses of Belgian manufacture. t The enormous resistance to the passage of light which is offered by ground glass is certainly worthy the attention of those using it for windows, etc. The discrepancy between Mr. King's results and my own, as regards ground glass, may perhaps be owing to the fact that the window glass used by myself was more coarsely ground than the lamp shades employed by him. NATURAL PHILOSOPHY". 149 We cannot doubt that the great loss of light proved by the experiments above given, is to be, in part at least, accounted for by the conversion of a portion of the light into heat, an effect perfectly in harmony with the the- ory of transverse vibrations as applied to explain the phenomena of polari- zation of heat. On this theory, heat and light are different effects produced by one and the same cause, and they differ physically only in the rapidity and amplitude of their vibrations. The screen through which the vibrations of light are propagated serves to diminish, first the rapidity of the vibrations requisite to produce the most infrangible rays, and in proportion as the trans- parency of the screen is diminished by any cause, inherent or superficial, this arrest becomes more and more complete. As the more rapid ethereal vibrations have probably the least amplitude, we infer from analogy in sound- waves, that as waves of least intensity have the greatest amplitude, so with the luininiferous ether the extreme red has but little brilliancy. Hence the loss of light from polished screens is small compared with that observed in screens of opaline or roughened glass. It would be instructive to examine the spectrum obtained from a pencil of rays under each of the cases given, by means of a sulphide of carbon prism. The subjett of absorption of light by screens has long since been carefully examined by Bouguer. By a photometric method essentially like Rum- ford's, Bouguer measured the loss of light in the beam of a candle compared with a flambeau, and also with the light of full-moon, in passing through sixteen thicknesses of common window-glass having a united thickness of 21 '43 millimetres = -85 inch. The mean loss of light shown by these trials was as 247 : 1, or over ninety-nine per cent of the whole quantity. Six plates of the purest mirror plate glass, having a united thickness of 15*128 millimetres, diminished the light in the ratio of 10 to 3, occasioning a loss of about seventy per cent of diffuse daylight. A mass of very pure glass, about three inches thick, diminished the light only about half the latter amount, owing to its being a single mass, and not cut up into many planes. He also measured the absorbing power of sea- water for light, and found, as the results of experiments made in France, and of observations also in the torrid zone, that at the depth of three hundred and eleven French feet the light of the sun would be equal only to that of the full moon, and at the depth of six hundred aad seventy-nine feet would wholly disappear. He estimates the transparency of the air as four thousand five hundred and seventy-five times greater than that of sea-water; and from the properties of a logarithmic curve (which he calls yraduhicique), whose functions he had determined experimentally, he seeks to fix the outer limits of the atmosphere. OX A PROBABLE MEANS OF RENDERING VISIBLE THE CIRCULATION IN THE EYE. The following article is communicated to Silliman's Journal by Professor Ogden W. Rood, of the Troy (N. Y.) University: Some time ago, while looking at a bright sky through three plates of cobalt-glass, I saw with astonishment that the field of view was filled with, and traversed in all directions by, small bodies resembling animalcules. They were seen on the blue field as yellowish spots, and always appeared elongated in the direction of their motion, which was, as a general thing, tolerably uniform. The same result was obtained by experimenting upon the eyes of a number of persons. Convex lenses of various foci, from three 13* 150 ANNUAL OF SCIENTIFIC DISCOVERT. inches to one-half inch, were now held before the eyes, so as to give tlie Mm- liirlit various decrees of convergence and divergence, without in the K-a.-t altering the appearance of the moving bodies; this seemed to indicate that their locality was in the retina or in its immediate neighborhood. A position near the axis of vision was selected, and observed, when it was found that these bodies in traversing this spot always pursued the same di- rection and path, disappearing at the same point; other positions near the axis gave like results. This would seem to preclude the possibility of the moving bodies being animalcules swimming in the humor of the eye; the most probable remain- ing supposition is, that they are blood corpuscles circulating in the retina or in its immediate neighborhood. The apparent diameter of these bodies when seen projected on a window six feet distant may be about ^ of an inch, which corresponds to about Tg^y^ of an inch on the retina. The average diameter of the blood globules is ^Vo of an mcn > but taking into account the fact that the shadows of the moving bodies are not well defined, the correspondence may be considered pretty satisfactory. The question now arises as to the manner in which the blue glass renders the circulation visible; for these moving shadows cannot be seen with dis- tinctness through red, orange, yellow, green, nor even purple, media; they are, on the other hand, well shown by a certain thickness of a solution of the cupro-sulphate of ammonia. Yellow solutions, when combined with the blue glass or blue solutions, render the circulation invisible, and it does not reappear till the yellow solution has been made so dilute as barely to preserve a yellow tint, and to transmit the spectrum almost unaltered. This shows that the indigo and violet rays are principally concerned in the pro- duction of this appearance; but that it cannot be attributed to fluorescent properties in the blood discs is indicated by the fact that the circulation can be seen through a considerable thickness of crown glass, through an infusion of red sanders Avood mixed with ammonia, as well as through a solution of the bisulphate of quinine. The only explanation that has occurred to me as being probable is the following: the blood discs are yellow, and consequently opaque, to a great extent, to the indigo and violet rays ; they would, therefore, in passing before the retina, cast shadows on it; now, the retina being already strongly im- pressed with blue light, that portion of it which was momentarily protected from the action of this light would experience the complementary sensa- tion, or would see, instead of a moving shadow, a yellowish moving streak. This explains, also, why the appearance is not seen with any distinctness in red, orange, yellow, or green light, for yellow media are, to a great extent, transparent to all their rays, and therefore fail to cast shadows. These observations, if new, may be of some interest to those engaged in the study of the physiology of the eye. ON OUR INABILITY FROM THE RETINAL IMPRESSION ALONE TO DETERMINE WHICH RETINA IS IMPRESSED. BY PROFESSOR WIL- LIAM B. ROGERS. ^ Although on first view it might be supposed that an impression made in H-I- eye must necessarily be accompanied by a mental reference to the par- ticular organ impressed, it will be seen from the following simple experi- NATURAL PHILOSOPHY. 151 ments that the impression of itself is not essentially suggestive of the special retinal surface on which it is received. Exp. 1. Let a short tube of black pasteboard, one-fifth of an inch in diam- eter, be fixed in a hole in the centre of a large sheet of the same material. Hold the sheet a few inches before the face of a second person, and between him and a bright window, moving it to and fro until the bright circular aper- ture of the tube is brought directly in front of one of the eyes, suppose the left eye; and let him fix his attention upon the sky or cloud to which the tube is directed. He will feel as if the impression or image of the hole belongs equally to both eyes, and will be unable to determine w r hich of them really receives the light. Exp. 2. Similar