nnnnnnmnnmiii inmi tiii i n i n i tn n in i iiiiiiiiiiiiiiiiiiii PUBLISHERS' ADVERTISEMENT. THE ANNUAL OF SCIENTIFIC DISCOVERY: OR, YEAR-BOOK OF FACTS IN SCIENCE AND ART, EXHIBITING THE MOST IMPORTANT DISCOVERIES AND IMPROVEMENTS IN MECHANICS, USEFUL ARTS, NATURAL PHILOSOPHY, CHEMISTRY, AS- TRONOMY, METEOROLOGY, ZOOLOGY, BOTANY, MINERALOGY, GE- OLOGY, GEOGRAPHY, ANTIQUITIES, &C. TOGETHER WITH A LIST OF RECENT SCIENTIFIC PUBLICATIONS ; A CLASSI- FIED LIST OF PATENTS ; OBITUARIES OF EMINENT SCIENTIFIC MF.N ; AN INDEX OF IMPORTANT PAPERS IN SCIENTIFIC JOURNALS, REPORTS, y the new process the liquid lead descends through an upright circular pipe, arranged over a reservoir of water, and near the bottom t is a fan wheel, which produces a constant current of air that meets the lead in its descent, and while it tends to decrease the rapidity of its fall in some degree, it also imparts to it a sufficient degree of cold to solidify the shot effectually, before they reach the reservoir, whence they are transported to the drying table, by means of an endless band of buckets, or elevators. New York Path Finder. CHAIN PIPES FOR TELEGRAPHS UNDER WATER. MR. WHISHAW presented some links of a full-sized pipe for inclos- ing the wires of electric telegraphs under water. The pipe was formed of links connected together by sockets, each link varying, ac- cording to circumstances, from 18 inches to 24 inches in length, and from 1 inch to 2^ inches internal diameter, according to the number of wires to be inclosed. These pipes, being of wrought-iron, are ex- ceedingly strong, and are required . merely as a protection to the wires, which are previously insulated by means of gutta percha. Pipes of somewhat similar construction are laid under the Rhine and other rivers in Prussia, where the underground system of telegraphs is adopted by the Prussian government (already to the extent of 1,200 miles), although many of the railway companies suspend the wires between posts, as practised in England, America, France, &c. 'Proceedings of the British Association. MECHANICS AND USEFUL ARTS. 49 * STONE-CUTTING MACHINE. A HIGHLY useful and important machine for the cutting and dress- ing of stone has been invented and patented by Mr. Charles Wilson, a mechanic of Springfield, Mass. It is remarkable for the simplicity, as well as the rapidity, of its operation, while the surface it produces on the stone is far more true and smooth than that where the chisel is used, so much so, that it would not pay to employ machinery in making the final finish, it being so easily rubbed down by hand. The wear of the cutters is much less in cost than that of chisels, and the stone is left perfectly sound, not being the least " stunned," as the phrase goes. The following is a brief description of the ma- chine : "From eight to twelve circular plates of steel, seven inches in di- ameter, and as thick as a common circular saw of that size, are placed alternately with iron washers one fourth of an inch thick and half an inch less in diameter than the plates. These washers and plates, be- ing firmly fastened together, form a compact cylinder or broad wheel, termed the 'cutter,' presenting to any surface over which it is rolled numerous steel edges, one fourth of an inch apart and one fourth of an inch deep. Two of these cylinders, being each supplied with an axis, are set to revolve in an ' iron head,' which is made to pass briskly back and forth across the stone as the latter is slowly moved along by a process like that used in saw-mills. The cylinders, taking only such motion as is given them by being rolled over the stone, the same motion as that of a carriage-wheel on a road, crumble the surface of the stone on their way to a powder, with a power which no granite can withstand, taking away a very little each time, but com- ing very often, and effectually doing the work. The cylinders are set in the head at an inclination of about 25 degrees from a horizontal line, about the same angle as that of the chisel when struck by the mallet, and so as to cut away the stone by a bevelled edge." In a recent exhibition of the working of this machine, a block of red sandstone, from the valley of the Connecticut, was placed on the " bed," and submitted to the action of the chisels. In eight minutes its surface, 4 feet long by 1 broad, equal to 6 superficial feet, was dressed smoother and more even than the common chisel could have done the work, and this with a moderate speed of the machinery. An engine of two or three horse power is sufficient to drive one machine. NEW BRICK-MAKING MACHINE. THIS machine, the invention of an Englishman, consists of an iron cylinder, which receives the clay at the top, and passes it through a number of knives, which are fixed to a centre-shaft, which act as tem- per^rs of the clay, and press it into a curiously-shaped screw. This in turn gives pressure to a chain of moulds, which passes up an inclined plane and delivers the finished bricks on a table. The entire motive- power is communicated by the upright shaft in the cylinder. By the application of an engine of three horse-power, the machine will make 5 50 ANNUAL OF SCIENTIFIC DISCOVERY. % 20,000 bricks in 10 hours; but it may also be worked by any other motive-power, and it can be moved from place to place. It is suited for making common and fire brick and tiles. MACHINE FOR TAKING THE YEAS AND NAYS. A COMMITTEE of Congress last year had, for some time, models of two or three machines for taking the yeas and nays, under examina- tion, and they finally reported in favor of one which is the invention of Mr. F. H. Smith, of Baltimore. It consists of a metallic case, two feet long and one broad, which is designed to be placed on the clerk's table. This case is composed of an upper and a" lower steel plate, through which small pistons of steel, equal in number to twice the whole number of members in the House of Representatives, play per- pendicularly ; they are divided into equal sets, one being intended for the yeas, and the other for the nays. Between the two plates, and above the pistons, when not in operation, a roll of the House, special- ly adapted for the machine, is easily inserted, with the words yea and nay printed on the right and left of each name. This roll, when in- serted between the plates, is readily adjusted by a gage, so that when one of the pistons is put in operation it ascends through the paper and cuts out the " yea" or " nay," as the case may be. The pistons are connected with the members' desks by means of wires passing under a false floor, where they are connected with two ivory keys, on which are engraved the votes corresponding to the pistons with which the wires are joined. The keys work by depression, like those of a piano. By the insertion of an additional plate in the case, the machine can be so controlled that no member can move his keys before or after the time allowed for voting. The roll must, for the purposes of the ma- chine, be printed in the order of the seats, and not alphabetically, as usual. The objection to this and all machines of the kind, however, is, that there is no way of detecting any derangement in the machine- ry, and a member may suppose that he is voting, when in reality the pistons do not work. SEWING-MACHINE. THERE is now in New York city a new sewing-machine in daily ope- ration, which, as far as it has been tried, has entirely answered the purpose intended. It has not, however, it is believed, been used ex- cept upon coarse material, and where the seam to be sewed is nearly straight. It is thus described in the New York Tribune: "On turning a crank with one hand, the machine sews seams of any length and any desired curve. The stitches are perfectly even and tight, and may be taken of any length. The work to be sewed is fastened in a sliding frame and gaged so that the needle shall strike the point of commencing the seam. The eye of the needle is near the point, and as it pierces the material the thread is carried through and caught by a hook, which holds it till the second stitch is made. It then drops the first, taking up the second and bringing it through it. MECHANICS AND USEFUL ARTS. 51 so that each stitch is looped upon the one behind it, the whole forming an interlinked chain. At the factory there are several machines, most of them employed in making salt-bags. About 15,000 are manufac- tured daily for the salt-works in this State. One machine will make from 800 to 1,000 bags per day." NEW MACHINE FOR SPINNING WOOL. Two citizens of Gardner, Me., claim that they have made an inven- tion which is destined to eifejct a revolution in wool-spinning. It is well known, by those who are acquainted with this kind of manufac- ture, that wool cannot, like cotton, be drawn out and then twisted, but that it must be done by the same operation. "The present method of performing the work is by means of "jacks," which take the \vool or roping that has previously been prepared by the cards, and spin it into thread for warp or filling. The "jacks" occupy a large space, and re- quire a great amount of labor and care to work them. But this new machine wholly dispenses with the "jacks," and the thread is both drawn out and twisted by the operation of this " revolving draft and wool-spinner." One of these machines occupies a space of only 4 feet 6 inches by 3 feet, and contains 20 spindles. It is claimed, that it will do the work of 50 spindles on a "jack" w r hich occupies a space of 10 feet by 7. In other words, 50 spindles of the "jack-" occupy 78 square feet, while the spinner occupies 13^. There is, besides this saving of space, a great saving of labor, as more work is per- formed with less manual assistance, and also a saving of power. IMPROVED MACHINERY FOR SPINNING YARN. MR. GEORGE H. DODGE, of Attleborough, Mass., has invented a valuable improvement in machinery for spinning winding-yarn, being a combination of the self-acting mule and throstle, and having many advantages over the common method of spinning, and equally appli- cable for filling and warp. In the room usually occupied for 1,000 mule-spindles i.500 may be placed, which will do the work of 3,000 spindles. It occupies the usual space required for warp-spinning, but will, it is said, spin 50 per cent, more yarn to the spindle than the best ring-bobbin spindle in use, and with a saving of two-fifths of the power. It is estimated to spin 100 per cent, more yarn than the flyer spindle, and with one half the power compared to the quantity. The spindle is more durable than the common one in use, being ta- pered to the top, and there being no bobbins or check-pins used, ic maintains its balance at any speed required. It is not liable to get out of order, and is much more convenient to piece up the ends when broken than the bobbin-frame. Messrs. Dodge & Sons have their entire mill upon this method of spinning, and say, that, from twenty- nine years' practical experience with other spinning, they believe it to be the best in use, and know that it is worthy the attention of manufacturers. They are daily producing more yarn from 2,320 spindles than they 52 ANNUAL OF SCIENTIFIC DISCOVERY. were able to do from about 4,600 spindles of the old plan commonly used, and have averaged the product of the above 2,320 spindles for nineteen successive weeks, without making any allowance for stop- pages, or hindrance from other causes, and have spun 61,287ilbs. yarn, No. 30, seven skeins to the spindle, per day. Hunt's Mer- chants Magazine. THE INVENTOR OF THE POWER LOOM. MR. ANDREW KINLOCH, the first man who ever weaved at a power- loom, died lately in Manchester, at the age of 90 years. In 1793, he set up the first power-loom in Glasgow, the propelling power being his own hand, and, after an outlay of $500, produced 90 yards of cloth. Shortly afterwards he removed to Milton Printfield, where forty looms were erected under his direction. In 1800, he went to England, setting up looms in various places in Lancashire, and more than once was in great danger of his life from the hand-loom weav- ers, who were jealous of his new invention. The power-loom re- mains as it was when he first invented it, with the exception of a few slight improvements. IMPROVEMENTS IN THE MANUFACTURE OF CARPETS. SEVERAL new improvements in the manufacture of carpets have been introduced into the English factories. One by Mr. Whytock, of Edinburgh, consists in employing printed warp in such a manner that all the wool is brought to the surface ; and the substance of such carpeting, in place of consisting largely of wool, as heretofore, de- pends on a less costly, but stronger material. By this invention the simplest loom only is required ; and the designer is in no way re- stricted as to variety of color. Any design of the artist may be executed, however many colors may be required, increased num- bers of colors not enhancing the cost. The peculiarity of this pro- cess consists in printing the separate yarns of which a warp is to be composed ; and this is done in such a manner that each yarn having had its colors applied thereto, and the proper number brought to- gether, side by side, to constitute a warp, the desired pattern is pro- duced. Each yarn is wound on a cylinder of large diameter, having 1 a graduated scale thereon, so that children (who apply the colors), having pattern-papers before them, have only to notice what colors are on the successive divisions of the pattern-papers, and to apply the colors, in succession, by passing color-rollers across the surface of yarn wound on the cylinder, thus making simple marks of color on the yarn, at intervals, which being according to the designs on the papers, -when the several yarns constituting a warp come together, the pattern is produced ; and the warp being woven into a fabric, with raised pile by the use of wires, the most beautiful and varied results are obtained." Another improvement lately introduced consists in printing Brus- sels carpets by a process similar to block-printing, using rollers, how- MECHANICS AND USEFUL ARTS. 53 ever, in place of blocks. Several specimens have been exhibited, which give considerable promise. The difficulty of printing Brussels carpets consists in getting the color to penetrate into the pile with- out spreading. This is only to be accomplished by repeated impres- sions; hence the difficulty of using blocks or rollers, so that they shall keep register with different colors, and at the same time repeat accurately several times on the same surfaces. This difficulty, it is believed, has been overcome by the above invention. Abridged from the Proceedings of the Royal Institution. THE CARPET MANUFACTURE IN AMERICA. THE most extensive manufactories in the United States are at Thom- sonville, Conn. They use 10,000,000lbs. of wool, and 10,000lbs. of flax-yarn per annum. They manufacture three-ply, Brussels, and Ax- minster carpetings of the richest patterns, the weaving at present being mostly done on hand-looms ; they are, however, about introducing power-looms into the factory, for weaving rugs and Axminster car- pets. The wool for Axminster carpeting is first woven into a web, and afterwards cut in strips, forming what is called chenille card; this is done upon a machine invented by Messrs. Davidson and Parks, of Springfield, Vt., which is the first and only one of the kind in the United States. The machine has over 200 cutters, or knives, which are attached to a cylinder, making some 300 revolutions, and cutting two full yards of the web per minute into strips, which being passed over a grooved cylinder, heated by having hot irons inserted within it, is prepared for weaving. Besides this large carpet-establishment, there is in this village a factory, 100 by 43 feet in dimensions, and five stories high, for the manufacture of knit shirts, drawers, and fancy ginghams. This establishment has about 30 sets of wool-cards, and 25 or 30 gingham looms. Scientific American. LOOM FOR WEAVING CARPETS. MR. JAMES M'KENZIE, of Schenectady, N. Y., has made some im- provements on the carpet-loom, which are claimed to be important. They consist, 1st, in a new mode of arranging and operating the shuttle-boxes ; 2d, in a new match-motion, or way, graduating the let-off speed of the warp-beam, and the take-up speed of the cloth- beam ; 3d, in a new stop-motion. The shuttle-boxes are of \ NEW PAINT. MR. W. LONGMAID, of London, has lately taken out a patent for a new way of treating the oxides of iron and obtaining products from them, for making paints. The mode of operation, which certainly has the merit of being novel, is as follows. The oxide of iron is re- duced to a powder, and then resin or tar is mixed with it in the pro- portion of 10 or 15 per cent., the larger quantity being preferable. The resin or tar, if used dry, should be pulverized, but when used in a semi-fluid state, it is mixed directly with the oxide and dried after- wards. The materials, being mixed, are put into retorts of cast-iron, which are about five feet long, and the only opening is closed with a cover. The retorts are then placed vertically in a furnace with the cover downwards to allow the escape of the gaseous matters evolved, and are allowed to remain at a fixed temperature for two hours after the gases have ceased to escape. After this they' are suffered to cool gradually, and the product obtained is a dark-colored matter, which when used as a pigment with oil forms a paint. If the escap- ing gases are preserved, they produce a volatile oil and an inflammable gas. SUBSTITUTE FOR FRESCOS. A METHOD of wall-painting has been invented at Berlin by a M. Fuchs, which promises to supersede the difficult al fresco process. It is stated to be much more durable and better adapted to the changes of a northern climate than the Italian method. An experiment was made a year ago to test the power of the colors to resist a very destructive agent, the result of which has just been ascertained. In {September of last year a portrait on stone was painted according to the new process by Kaulbach, and given for trial to the director of the Royal Museum. It has ever since been deposited in the chimney, exposed to a twelvemonth's smoke, and when recently taken out it was covered by a thick coating of soot that was removed with difficulty, but the painting beneath was found uninjured, with the colors clear and briefht. o MECHANICS AND USEFUL ARTS. 95 IVORY AS AX ARTICLE OF MANUFACTURE. Ax English gentleman stated some interesting facts concerning ivory in a recent lecture at Sheffield. There are several sorts of ivory, differing from each other in composition, durability, external ap- pearance, and value. The principal sources from which ivory is derived are the western coast of Africa and Hindostan. Camaroo ivory is considered the best, on account of its color and transparency. In some of the best tusks the transparency can be discovered even on the outside. The manufacturers have a process by which they make poor ivory transparent, but it lasts only for a short time. A third kind of ivory called the Egyptian, has lately been introduced, which is considerably lower in price than the Indian, but in working there is much waste. By an analysis, the African ivory shows a proportion of animal to earthy matter of 101 to 100; the Indian, 76 to 100; and the Egyptian, 70 to 100. The value of ivory consumed in Sheffield, where it is much used in making handles for cutlery, is about $140,000, and nearly 500 persons are employed in working it up. To make up the weight of 180 tons consumed in that place, there must be about 45,000 tusks, whose average weight is 9 pounds each, though some weigh from 60 to 100 pounds. According to this the number of ele- phants killed every year is 22,500 ; but allowing that some tusks are cast and some animals die, it may be fairly estimated that 18,000 are killed every year merely for the ivory, which is contrary to the usual belief that the ivory used comes from the tusks cast by living ele- phants. These estimates, it will be seen, are for Sheffield merely. TO RESTORE DECAYED IVORY. MR. LAYARD, in his explorations among the ruins of Nineveh, dis- covered some splendid works of art" carved in ivory, which he forward- ed to England. When they arrived there, it was* discovered that the ivory was crumbling to pieces very rapidly. Professor Owen was consulted to know if there was any means of preventing the entire loss of these specimens of ancient art, and he came to the conclusion that the decay was owing to the loss of the albumen in the ivory, and therefore recommended that the articles be boiled in a solution of albumen. The experiment was tried with complete success, and the ivory has been rendered as firm and solid as when it was first en- tombed. HOLLOW BRICKS. COMPRESSED bricks, with a longitudinal perforation, have been brought into use in England, in the construction of edifices. The plan, however, is not of recent origin, having been known to the an- cients, and applied in the construction of some of the early Christian churches in Italy. These bricks, being considerably lighter than the solid ones, may be used with advantage and economy in the construc- tion of arches, and the partition-walls of dwelling-houses and other 90 ANNUAL OF SCIENTIFIC DISCOVERY. buildings. They have also the recommendation of combining dryness with facility of ventilation. London Ailienccum. AMERICAN QUEENSWARE. THE manufacture of Queensware, like that of glass, is rapidly ad- vancing in this country. There are at Liverpool, Ohio, seven dif- ferent establishments, giving active exercise to a large amount of cap- ital, and employing upwards of 180 workmen. They turn out more than $70,000 worth of the ware annually, and the Pittsburg Gazette says : " The ware which is of two colors, either of a light yellow or of a dark mahogany hue, is as strong and well glazed as any we have ever seen, while the patterns are, in many instances, very chaste and graceful. This branch of our manufactures has sprung up within the past few years, and has already driven the English yellow ware from our market. It is sold in vast quantities in New York, Philadelphia, and the other Eastern cities, as well as in Pittsburg, Cincinnati, Louis- ville, St. Louis, New Orleans, and the rest of the Western towns." At Zanesville, Ohio, there are also large factories. CALCINED GRANITE AS A MATERIAL FOR FICTILE PURPOSES. ^ MR. ARCHIBALD M'DONALD has lately been engaged at the Seyton Pottery, Aberdeen, in making some experiments upon calcined gran- ite as a substitute for clay in the manufacture of pipes and other earth- en-ware articles. He states in a note to us, that the material stands a strong fire and is not affected by transitions from heat and cold. The native color of the stone can be nearly retained in the formation of busts, statues, vases, urns, and general pottery, as also in chimney- pieces, spouts, &c. In such articles as are intended to withstand the effects of great heat, where an extract only of stone is used, the color cannot be kept so well, as, for example, in retorts and crucibles; but any preparation of the material, when once properly finished, may be heated to whiteness without injury. The experiments have been car- ried on under great disadvantages, but have thus far all been satisfac- tory. Practical Mechanic's (Scotch) Journal. THE EFFECT OF STEAM UPON TIMBER. M. VIOLITTER has lately presented to the French Academy a very able communication on the desiccation of different kinds of wood by steam. He ascertained that steam raised to 482 degrees Fah- renheit was capable of taking up a considerable quantity of water, and, acting upon this knowledge, he submitted different kinds of oak, elm, pine, and walnut, in pieces about 8 inches long and half an inch square, to a current of steam at 7% pounds' pressure to the square inch, which was afterwards raised to 482 degrees. The wood was thus exposed for two hours. It was weighed before it was exposed to the steam, and afterwards placed in closely stopped bottles until it became cool, MECHANICS AND USEFUL ARTS. 97 when it was again weighed, and showed a considerable loss of weight, which increased with the increase in the temperature of the steam. For elm and oak the decrease was one half, fur ash and walnut two fifths, and for pine one third. The woods also underwent a change of color as the heat was rising from 392 to 482 degrees ; the walnut became very dark, exhibiting a kind of tar formed in the w r ood by the process, which was found to have a preserving effect on the wood. It was ascertained that wood thus treated became stronger, having an increase in the power of resisting fracture. The maximum heat for producing the greatest power of resisting fracture was, for elm from 302 to 347 degrees; for oak, walnut, and pine, from 257 to 302. The oak was increased in strength five ninths, walnut one half, pine two fifths, and elm over one fifth. By this process of steaming, the fibres of the wood are drawn closer together, and maple and pine treated with steam at a temperature of 482 degrees were rendered far more valuable for musical instruments than by any other process heretofore known. These, however, are but preliminary experiments, which it is expected will lead to very important results. DISSOLVING BONES BY STEAM. A STATEMENT has lately been made to the Highland Agricultural Society of Scotland in relation to pulverizing bones by steam, and it was asserted that bones of any size could be reduced to a soft mass in the following manner. All the machinery necessary is a small boiler with a steaming-vessel connected with it capable of bearing a pressure of twenty-five or thirty pounds to the square inch. The vessel being filled with bones and subjected to the action of steam above the level of the boiler (as they will not dissolve if covered w 7 ith water), at twenty-five pounds' pressure, for a few hours, they will become quite dissolved, thus saving all the expense of grinding and the sulphuric acid commonly used, which amounts to double the price of the rough bones. By this new process the bones are so much softened that they can be crushed by the hand. Dr. Anderson, the chemist, thinks the steaming process cheaper than the old one, and Prof. Traill considers it preferable, because all the animal matter, a portion of which is commonly lost, and the gelatine are saved. Albany Cultivator. CINCINNATI LARD AND OIL MANUFACTURE. WE learn from the Cincinnati papers that there are upwards of thirty large establishments in that city employed in the manufacture of lard-oil, which is accomplished by divesting the lard of one of its constituent parts, stearine. The largest of these, whose operations are probably more extensive than any other in the United States, has manufactured heretofore into lard, oil, and stearine 140,000lbs. month- ly, all the year round, and the great increase of hogs for the pres- ent season will probably enlarge that business this year 50 per cent. It is calculated that 1 l,000,000lbs. of lard will be run into lard-oil this year, two-sevenths of which aggregate will make stearine, the residue 9 98 ANNUAL OF SCIENTIFIC DISCOVERY. oil, say about 24,000 barrels of 42 gallons each. Much the larger share of this is of inferior lard, made of mast-fed and still-fed hogs, the material, to a great extent, coming from a distance ; hence the poor quality of Western lard-oil. Lard-oil, besides being sold for what it actually is, is also used for adulterating sperm-oil, and in France serves to materially reduce the cost of olive-oil, the skill of the French chemists enabling them to incorporate from 60 to 70 per cent, of lard-oil with that of the olive. There is also an establish- ment in that city which, besides putting up hams, &c., is extensive- ly engaged in extracting the grease from the rest of the hog, and will probably this year operate in this way on 30,000 hogs. It has seven large circular tanks, six of capacity to hold each 15,000lbs., and one 6,000lbs. These receive the entire carcase, with the exception of the hams, and the mass is subjected to steam-process, under a pres- sure of 70lbs. to the square inch, the effect of which operation is to reduce the whole to one consistency, and every bone to powder. The fat is drawn off by cocks, and the residuum, a mere earthy sub- stance, is taken away for manure. Besides the hogs which reach this factory in entire carcases, the great mass of heads, ribs, back- bones, tail-pieces, feet, and other trimmings of the hogs cut up at the different pork-houses, are subjected to the same process, in order to extract every particle of grease. This concern alone is expected to turn out this season 3,600,000lbs. of lard, five sixths of which is No. 1. Six hundred hogs daily pass through these tanks one day with another. The stearine expressed from the lard is used to make candles by being subjected to hydraulic pressure, by which three eighths of it is discharged as an impure oleine ; this last is employed in the manufac- ture of soap ; 3,000,000lbs. of stearine have been made in one year into candles and soap in these factories, and they can make 6-OOOlbs. of candles per average day throughout the year. Hunfs Merchants' Magazine. ELASTIC MOULDS. THE art of making elastic moulds, for copying statuary, designs, &c., has lately been introduced into the Sheffield (England,) School of Design. It possesses great advantages over the old plan, as the moulds may be made at small cost and with great rapidity. That which would oc- cupy five or six days in the modelling, may be furnished by this pro- cess in half that number of hours. By* the facility thus afforded, beautiful forms may be multiplied so cheaply as to be brought within the reach of all. The principal material used for the elastic moulds is glue or gelatine. The best fish-glue will answer as well as gela- tine, and is much cheaper. The material is dissolved, like glue, in a vessel placed over the fire, in a pot of hot water, stirring it during the process. To each pound of the gelatine it is necessary to add three quarters of a pint of water, and half an ounce of beeswax. It is ready for use when about the thickness of syrup. The model must be oiled carefully with sweet oil, and the composition must be poured upon it while warm, but not boiling. Having set, it may be taken off the model. When the model is small, it, should be placed in MECHANICS AND USEFUL ARTS. 99 a case, which gives facility for shaking the mould well when the plas- ter is poured, so as to drive it well into the crevices. The plaster should be fine ; and, in order that it may harden and set quickly, about half an ounce of alum should be added to each pint of water used in mixing it. Before using the mould, it should be carefully oiled. Great care is required in mixing the plaster and watching it when in the mould, for if it be allowed to remain long enough to heat, the mould is destroyed. Sheffield (England} Independent. ^ DISTILLATION OF SALT WATER. MANY machines have been invented for the purpose of distilling fresh water from salt water, but hitherto there has always been some objection to each and all of these contrivances. But the British gov- ernment seem to have satisfied themselves that a Mr. Grant has invented something which will answer the purpose, for they have lately pro- vided several of their vessels of war with his machine. He calls it " The Distilling and Cooking Galley." By some improvements made since the first invention, the quantity of fresh water obtained by the distillation of salt water during the time it is necessary to keep the galley-fires lighted for the purpose of cooking will, on the average, supply every person on board the vessel with one gallon of distilled water every day. This water is preferred to that usually supplied to ships for drinking and culinary purposes; and, as it passes imme- diately from the condenser to the water-tanks, it enters the latter at the temperature of the sea. In a few hours the simple motion of the ship, without any chemical means, completely aerates the water, and removes the vapid flavor which characterizes distilled water. Experi- ments are in progress with a view of imparting at the moment of dis- tillation the oxygen of which the water is deprived in the process, and thus giving to it the briskness of spring water. This is proposed to be effected by passing a current of electricity through the particles of water by means of a very simple, self-acting apparatus. Abridged from the London Times. FENCE FOR FIELDS LIABLE TO BE OVERFLOWED. THIS simple invention is patented by Wm. Miller, of Pennsylvania. Two posts should be taken, about 7 inches square, and 5 feet long, and sunk 3 feet in the ground. A triangular mortise, 2 inches deep, 4 high, and 5 wide, must be cut in the side of the posts 3 or 4 inches from the ground, and a shallow notch in the form of a V must also be cut in the top of the posts, and rails, corres} onding in form with this notch, are laid on them. The lower rail i., fitted into the mortise by making the ends round, like gudgeons, which are to be inserted in the inorti-f. cadi gudgeon being about 2-1- inches in diameter, and of any length. The boards being tla-n nailed on the side of the rails against which the water flows, whenever the flood strikes them, the round gudgeons will slide up the sloping sides of the mortise, and the upper rails will rise out of the notches, so that the entire pannel will fall flat upon the ground, being secured by the gudgeons. After the flood has 100 MECHANICS AND USEFUL ARTS. subsided, it is only necessary to lift up the fallen panels, and the fence will be as firm as when first erected. Albany Cultivator. WAGONS AND CARTS. A FARMER in England, named Edward B. Liddington, has produced a prize-essay on the comparative merits of wagons and carts, which should arrest the attention of our farmers; for if he is right, they in general are wrong. After five years' experience with wagons, and nearly the same with one-horse carts, on a farm of one hun- dred and seventy acres of arable and eighty acres of pasture land, he came to the conclusion that the carts were of the greatest advantage. As our farmers all use wagons, let them pay some attention to his statement. He says, " I have no light ploughed land, nor have I more than twenty or thirty acres of very heavy land. I will, there- fore, relate my actual experience. In the employment of wagons and the old broad-wheeled dung-carts, I required one wagon, one cart, and three horses, to every fifty acres of arable land. I also kept a light cart for general purposes. Now that I am employing carts, I find that I get through my work much more easily with two horses and two carts to fifty acres." In the calculation of items, his saving was nearly four dollars on the cultivation of one acre, in the year. Again he says, it is admitted that one horse attached to a given weight will move it more easily than two horses attached to double that weight. This arises, not only from the advantage gained by having all the power of draught close to the work, but also all the power applied at the same moment, which is almost impossible where two or more horses, having differ- ent wills and steps, are attached to the weights; and for the same reason, one horse will travel more quickly. When a cart is filled, there is no delay in attaching the trace-horses, during which operation one horse would be two hundred yards on the road. I know this might be done more quickly by having men ready to change the horses, as in the practice of opposition coaches ; but I am speaking of the matter-of-fact working of the system. Then, again, when the load is deposited, the one horse turns in much less time than the two or three. These facts are too self-evident to admit of their contradiction ; indeed, I believe the economy of carting ma- nure with one-horse carts is generally allowed, but the employment of them in harvesting is much objected to. In this respect, however, I find them equally expeditious and economical. My actual experience is, that three carts, with the harvest frames attached, will convey as much hay or corn in the straw as two wagons, and that they are bound with the ropes in the same time ; therefore no time is lost in the binding. They are easier to pitch into than wagons, and not more difficult to unload ; and all the advantages are gained of speed in travelling. My attention was first drawn seriously to the subject, from hiring a man to draw some stones for draining. He came with a horse only fourteen hands high, and a small cart, when the work he accom- plished so surprised me, that I at once decided to try two fight carts, MECHANICS AND USEFUL ARTS. 101 which, after succeeding- well in all other operations, I employed in the harvest-field, and being fully satisfied with them in this capacity, I soon discarded every wagon from the farm. New York Farmer and Mechanic. LONDON COAL EXCHANGE. THE desiccated floor of the London Coal Exchange consists of up- wards of 4,000 pieces of wood, of various kinds and qualities. The great feature of the affair is, that the whole of these pieces were, only a few months since, either in the tree in the growing state, or cut from wet logs, and were prepared for use in the course of a few days, by a new method of seasoning. The names of the woods thus introduced are black ebony, black oak, common and red English oak, wainscot, white holly, mahogany, American elm, red and white wal- nut (French and English), and mulberry. It is mentioned as a proof of the rapidity of this mode of seasoning, that the black oak is part of an old tree which was discovered and removed from the bed of the Tyne River about the latter end of last year. The mulberry- wood, introduced as the blade of the dagger in the city shield, is no less than a piece of a tree which was planted by Peter the Great, when working in this country as a shipwright. The patentees state that no one piece of the 4.000 occupied more than ten or twelve days in seasoning. London Builder. FIRE-AXXIIIILATOR. A NUMBER of experiments have been made at the London Gas Works, with " Phillips' s Fire-Annihilator." These were preceded by an explanation from Mr. Phillips of the manner in which he was led to the discovery, and of the principles upon which its success de- pends. He stated that, while watching a volcanic eruption in the Mediterranean, he observed that the huge column of water which was discharged from the crater did not extinguish the flame which accom- panied it, while the smoke of a brushwood fire swept by the wind put out another brushwood fire near it. He then introduced the " fire- annihilator," which at once extinguished very large fires fed by the most combustible materials. The extraordinary speed, ease, and cer- tainty with which the invention acted, excited the surprise and admi- ration of many scientific gentlemen who were present, and there can be little doubt that the " fire-annihilator " is a very valuable addition to the discoveries of the age. In construction and application, it has the great advantage of being extremely simple, and it is quite porta- ble, and capable of being placed where it would be most accessible when needed. The gases which it evolves, and which are found so efficacious in extinguishing flames, are produced from a compound of charcoal, nitre, and gypsum, which is ignited by breaking a bot- tle containing sulphuric acid. The acid drops upon chlorate of potass and sugar, and instantly a large body of vapor is evolved with great force from a tube connected with the metal chamber in which the whole materials are inclosed. Tins vapour extinguishes the flames with a rapidity which is truly marvellous. London Athenaum, Sept, Q* 102 ANNUAL OF SCIENTIFIC DISCOVERY. VALUABLE DISCOVERY IN THE MANUFACTURE OF INDIA-RUBBER. A GREAT part of the usefulness of India-rubber depends upon the process known as " vulcanizing," whereby textures of which it forms a part are exempted from the action of heat and cold. This process has hitherto been performed by the mixture of sulphur and lead, or of sulphur alone, with the rubber. A discovery just made in England, by a Mr. Burke, will put an end to the contests between patentees of various processes in this country, by introducing a new process, which is simpler and cheaper than the old ones, and dispens- ing with the use of sulphur, as it does, avoids the UHpleasant smell caused by that substance. Though patented in England, this new process has already been employed in this country, so that it cannot now be monopolized here. The discovery may be succinctly described as follows. We con- dense from the language of the inventor. Mix 15 parts of golden sulphuret of antimony with 100 parts of India-rubber, and when thoroughly " masticated," as known to man- ufacturers, the articles are to be made up, and then submitted to heat in a boiler under pressure at a temperature varying from 260 to 280 Fahrenheit. A manufacturer of this city has shown us specimens made by mix- ing a much larger portion of golden sulphuret of antimony with the same quantity of rubber named above. The product is exceedingly elastic, tough, and beautiful in appearance, while it is perfectly free from the smell of sulphur. At the same time it has no appearance of bloom, which is a point of the first importance. The heating of compounds of rubber in a boiler under pressure was first introduced from England into the United States some three years ago. Since then, the manufacture of rubber goods has more than doubled in amount. This new discovery, by which antimony takes the place of sulphur, will extend still further this branch of American industry, than which none has received more attention from scientific men. The same inventor describes a new kind of cloth in these words : " The second part of my invention refers to the manufacture of water-proof cloths or garments known as single textures, and consists in removing the shiny or polished appearance of the surface thereof, which is very generally objected to from its resemblance to common oiled or painted cloths. In order to effect this improvement, I mix with caoutchouc, either prepared as above or not, from ten to fifteen per cent, of ground silk, cotton, or wool (after the manner of flock), and dissolve it in a suitable menstruum, or I mix the flock with the caout- chouc when dissolved. With this solution I coat the surface of the cloth, which has previously been prepared with the water-proof com- position in the ordinary manner of such manufacture, and thereby impart to the water-proof surface an appearance greatly resembling woollen cloth. This cloth may be afterwards put through the heating process, and another cloth or fabric cemented thereto as a lining, if required." New York Tribune. NATURAL PHILOSOPHY THE ELECTRIC LIGHT. MUCH has been said and written upon the application of the power- ful light produced by artificial electricity to the purposes of illumina- tion. Many varieties of apparatus have been invented, to all of which there has hitherto been some great objection. Perhaps the greatest difficulty to be surmounted has been that of rendering the light steady and permanent by mechanical means, so that it shall not require any attendant. This difficulty, at least, seems to have been obviated by the invention we are about to describe. The light is called "Stake's Patent Electric Light," after its in- ventor. It is produced from a galvanic battery of moderate size, em- bracing in its construction and elements several features, which are claimed to be improvements, the object of which is to render the battery constant, continuous, and regular in its action, and economical in its cost. By means of solid copper wires the electric fluid is conveyed to the lamp, which may be placed on a table or suspended from the ceiling. In this lamp are two cylinders of carbon, which are used as electrodes, that is to say, the current of electricity is passed from one to the other as they stand end to end, their ends being separated from one twentieth to one half an inch, according to the power of the cur- rent applied ; and these cylinders are moved by a clock-work arrange- ment, in proportion as they are consumed, at a speed which is regu- lated by the currents. To render the light continuous, it is necessary that these two pieces of carbon should first be brought into actual con- tact, so that the current may pass and then be separated to a short distance. This is accomplished, and here is the grand feature of the invention, by the current itself, without manual aid. As the carbon gradually wears away, at the rate of about an inch in t\vo hours, the same regulated distance between the two electrodes is preserved by like means. The apparatus for effecting this self-regulation is an electro-magnetic instrument, placed directly under the plate of the lamp, through which the current of electricity is caused to pass. The principle of this instrument is very ingenious, in some degree resem- 104 ANNUAL OF SCIENTIFIC DISCOVERY. bling a galvanometer ; the galvanic current, passing through a coil of wire, magnetizes a bar of soft iron, which is passed through the coil ; and in proportion as the current is strong or feeble, the magnetized bar rises or falls. When the current is in excess, it actuates an escapement, and the two electrodes are drawn to the required distance apart; and when the current passing is less than the regulated quanti- ty, the motion is reversed, and the electrodes are drawn nearer to- gether. Thus the light is rendered steady and constant, while no more of the fluid is allowed to pass than is developed in light, effecting a great economy of battery-power. To prevent injurious vibrations or sud- den movements of the iron bar, it is provided with a rack, wheel- work, and fly. Another improvement consists in giving the upper electrode the form of a circular disk made to revolve slowly in con- tact with a fixed scraper, which keeps the edges clean and i'ree from the particles of carbon projected upon it from the lower electrode. The carbon is prepared by forming a powder of charcoal into paste with melted brown sugar, pressing it into iron moulds, and baking it in the moulds at a red heat, and afterwards in a crucible at a white heat. There have been several public exhibitions of this light, all of which have been successful. In one case it was exhibited in the large rooms in Hanover Square, London. The rooms were, as usual, lighted with chandeliers of wax candles, with a considerable number of oil- lamps ; the total amount of light being considered to be equal to 200 or 300 wax candles. On the lecture-table was the light apparatus, covered with a tall glass shade. All things being made ready, the galvanic circuit was completed, and in a few seconds the whole apart- ment was filled with such a blaze of diffusive light, as caused the now dimly burning candies and lamps to assume the muddy and lack- lustre aspect they bear in ordinary sunlight. Every object in this large room was brilliantly illuminated, and as an assistant turned the light on and off at pleasure, the transition was as violent as from broad clay to evening twilight. The paintings on the ceiling were finely displayed ; and, what was very remarkable, the tone of the colors was precisely similar to that which they are seen to possess in daylight. All the delicate intershadings of the yellows, grays, flesh-tints, and even of greens and blues, were brilliantly defined, and in all respects conveyed the daylight impression to the eye. The light was about equal to that of 700 or 800 standard wax candles, yet a lady's bonnet might have covered the entire apparatus; and the actual source of light did not occupy an area of more than an inch in every direction, if so much. The rays were then concentrated by a powerful lens, and directed upon some pictures, which were placed for the pur- pose on the side of the room, and the colors could be as clearly seen as by the light of the sun. By means of a glass prism, a spectacle yet more beautiful was shown : this was the display of the prismatic spectrum, the entire number of the rays being present, and in brilliancy not to be distin- guished from the same as shown by the decomposition of the true NATURAL PHILOSOPHY. 105 solar light. Perhaps one of the most striking displays of the charac- ter of the electric light followed. The electrodes were immersed in a globe of water, and still the light continued gleaming forth in all its brilliancy. Those who are familiar with the oxyhydrogen light, and the peculiarly white and somewhat intense light of the camphine lamp, might have felt doubtful of the result of a contrast with these ; but the "electric effulgence outshone both to a remarkable degree. It was stated at the time, that a volume of light equal to that of ^ 10,000 wax candles could be evolved by the apparatus from a square inch of actual illuminating surface. It was said that a light of from one candle to 100,000 might be obtained, and sustained, by this new system ; and with regard to the cost of production, the light equal to 100 wax candles was obtainable at the rate of a penny an hour, or about, as it is stated by the inventor, one twelfth part of the cost of gas for the same period, and producing the same degree of illumina- tion. The character of the electric light presents several remarkably in- teresting features, most of which belong to no other artificial light whatever, and assimilate it to that of the sun itself. The heat evolved is vastly disproportionate to the light produced, as may be conceived from the fact, that the lamp, when pouring forth a volume of light equal to 800 candles, did not emit more heat than that of one Argand lamp equal to six or seven candles. The light has been displayed, not only in air and under water, but also in alcohol, ether, sulphuret of carbon, and in atmospheres of carbonic acid, nitrogen, and hydro- gen. The apparatus constructed, for domestic use gives a light equal to from eight to forty candles. There is another point which appears to be important in consider- ing the applicability of this beautiful light to the illumination of streets or great areas, and that is its diffusibiiity. The ordinary modes of illumination are incapable of giving luminosity to the solid and aqueous particles in the atmosphere for any considerable extent, but the electric light effects this admirably, for even if a person places himself in the shadow under a wall, he can easily see to read ; so that the argument brought up by some, that, in attempting to light large spaces with a single light, much of the area must be thrown in- to the shade, is of no weight. But there is one chemical peculiarity about this light which de- mands a brief notice. It is found to possess those chemical powers of decomposition, which have been regarded as peculiar properties of the solar light, and which are known under the name of actinism. Preparations of silver, which turn black when exposed to the sun's light, blacken also before the electric light ; and the chemical union of mixed gases, hydrogen and chlorine, has been effected by placing a jar containing them hi the light of the electric lamp. APPARATUS TO PRESERVE THE ELECTRIC LIGHT CONSTANT. Ax the sitting of the Paris Academy of Sciences on the 15th of Jan- uary, M. L. Foucault reminded the Academy that five years ago 106 ANNUAL OF SCIENTIFIC DISCOVERY. he had exhibited an apparatus, in which the electric light was used to obtain upon a screen a magnified image comparable with that given by the solar microscope itself. But in this instrument there was a great inconvenience arising from the necessity of continually watching and adjusting the charcoal points. This apparatus he lias since modified so as not only to keep the poles at the same distance apart by a spon- taneous action, but also to keep the radiant point immovable. These results he obtains by the following arrangements. The two points are pressed together by springs, but cannot move in that direction without setting in motion a train of wheels, the last of which is controlled by an escapement. The current of the apparatus passes around an electro-magnet, the energy of which of course depends upon the in- tensity of the current ; this electro-magnet acts upon a piece of soft iron, which is pressed in the opposite direction by a spring. Upon this soft iron is mounted the detent which checks the train of wheels before mentioned, and the direction of the movement is such, that, when the current becomes stronger, it presses upon the wheel-work, and when it becomes weaker, releases it. And, -as the current be- comes stronger or weaker according as the poles approximate to or recede from each other, it will be seen that the poles become free to approach each other as soon as their distance apart increases, but that they can never come in contact, because the increasing strength of the magnetism developed by their approach presents an insurmountable obstacle, which removes itself as soon as the interpolar distance has again increased. The approach of the charcoal points is therefore in- termittent, but the periods of rest and movement succeed each other so rapidly as to be equivalent to a continuous progression. M. Foucault requested the appointment of a committee to investi- gate the originality of his invention, as it happens to be very similar to that invented by Mr. Staite. The committee was appointed, and reported " that the means invented by M. Foucault originated with him, and were independent of those invented by Mr. Staite for the same purpose." At a later meeting it appeared that M. Gaigneau, on the 14th of January, 1848, had taken out a patent in London, in the name of Mr. W. Petrie, for an apparatus which fulfilled the same conditions in the same manner; but there was also in the same patent a method of producing an intermittent light for light-houses, in which the period of intermittence could be regulated beforehand. It would thus appear that, within a few months of each other, Messrs. Foucault, Staite, and Petrie, each without the knowledge of the others, contrived methods for producing a constant electric light, which were almost exactly similar. EXPERIMENTS WITH THE LIGHT OF THE VOLTAIC ARC. AFTER giving the description of his apparatus mentioned above, M. Foucault continued : " We thus obtain by means of my instru- ment arcs of all kinds, which are persistent, and which can by the aid of lenses be thrown upon a screen, so that their physical appear- ance can be contemplated, or upon a linear diagram, so that they can NATURAL PHILOSOPHY. 10*7 be analyzed by the prism. A commutator is also used to invert the direction of the current, for the purpose of better exhibiting that part of the action due to the positive and negative poles. This study, the end of which cannot yet be seen, has already given me the following results. " The arc from charcoal points furnishes by the prismatic analysis the most curious and brilliant appearance. Its spectrum is crossed along its whole extent by a multitude of irregularly-grouped lumi- nous lines ; but among these a double line is remarked situated on the boundary between the yellow and the orange. As this double ray recalled by its form and position the line D of the solar spectrum, I was desirous of examining whether it corresponded to it, and for want of instruments to measure the angles I had recourse to a pecu- liar process. I projected upon the arc itself an image of the sun formed by a converging lens, which permitted me to observe at once the solar and the electric spectra superposed, and in this way I ascer- tained that the double bright line of the arc coincides exactly with the double black line of the solar light. This process of investigation furnished me with the means of several unexpected observations. In the first place, it proved to me the extreme transparence of the arc, which but faintly shadowed the light of the sun. It showed me that this arc placed in the path of a beam of solar light absorbed the ray D, so that this line of the solar spectrum is considerably strengthened when the two spectra are laid exactly over each other. When, how- ever, they overlap, the line D appears blacker than usual in the solar light, and comes out more brilliant in the electric spectrum, so that we can easily judge of their perfect coincidence. Thus the arc offers to us a medium, which itself emits the rays D, but at the same time absorbs them when they come from another source. To make the experiment still more decisive, I threw upon the arc the reflected image of one of the incandescent points of charcoal, which, like all bodies in ignition, gives no lines, and under these circumstances the line D appeared as in the solar light. Passing, then, to the examination of the arcs furnished by other matters, I have almost always found the line D positive and at its place, and I have ascertained that it coincides exactly with the ^brilliant line from the flame of a candle. When the poles employed are of metals which give the ray D but feebly, such as iron and copper, it can always be revived with ex- traordinary intensity by touching them with potassa, soda, or by one o? the salts formed by lime, or by one of these bases. Before conclud- ing any thing from'the almost constant presence of the line D, it will without doubt be necessary to ascertain whether its appearance does not indicate the existence of the same substance mixed with all arc- conductors. Nevertheless, this phenomenon already appears to us a pressing invitation to the study of the spectra of the stars, for if this same line should be discovered, stellar astronomy will be able to make the discovery available. " I also endeavoured to make these different arcs coincide, and I was again astonished by the appearance of unexpected phenomena. During the coincidences of these various spectra I saw the electric 108 ANNUAL OF SCIENTIFIC DISCOVERY. lines stand out upon the comparatively uniform ground of the solar spectrum, so that it might be seen that, notwithstanding their appar- ently accidental grouping, they all possessed the tint of color corre- sponding to their refrangibility. But what is peculiar in this experi- ment is, that among these electric lines some possess an intensity enor- mously superior to that of the corresponding solar ray. Especially in the arc from silver there is a green ray, so to speak, inextensible by the prisms, and of a dazzling color. It is a true source of simple , light, and as it is insulated, and as the arc from silver is transparent, tranquil, and durable, there is nothing to prevent this ray from being made the source of a green light as intense as may be wanted, and from being utilized for the demonstration of phenomena heretofore in- dicated by theory alone. Other very intense rays have also their fixed places in different parts of these spectra and even at their ex- tremities, and there is great probability of discovering isolated lines, the rays corresponding to which cannot be seen in the solar light." L'lnstilut, Feb. 7. POLARIZATION OF GALVANIC LIGHT. PROFESSOR C. G. PAGE, of the Patent-Office, has communicated to Sittiman's Journal, No. 21, a paper on this subject. "Having seen it stated, upon the authority of Arago, that the light of the galvanic arc, like that from incandescent gas, was not polarizable, I have been induced to repeat the experiment, with a view of testing, for my own satisfaction, a principle so important in a theoretical point of view. The experiment was briefly performed, and only with reference to the simple fact itself. The battery employed was a Grove's, of fifty pairs platinum plates, four inches square, and double surface of zinc. By means of a Nicols prism, and one reflection from a plate of mica, the light from the arc between the charcoal points w r as distinctly polarized. Its property in this respect was much more decided when the arc was first formed than when it had continued for a few seconds. It may be observed, that when the electrodes are first with- drawn the arc is very intense, arid does not rise in the arched form immediately, but as soon as the charcoal points have become intense- ly heated, the arc becomes elongated and rises, from the upward cur- rent of air, and the upper portion of the arc is then feeble in intensity. This upper portion did not appear at all polarizable upon a single re- flection, but upon two reflections was decidedly so." VOLTAIC IGNITION. THE following is an abstract of a paper recently read before the Royal Institution (England), on " Voltaic Ignition," by Mr. Grove, well known for- his researches on electricity and galvanism. Mr. Grove introduced the subject by asserting that the only true philo- sophical idea of heat W 7 as that which regards it as a repulsive power, that with the single exception of water, and other bodies which assume a crystalline form when about to freeze (a condition which he NATURAL PHILOSOPHY. 109 ascribed to a polar state which these substances then take), all matter expands by heat. This expansion of matter, so caused, can be com- municated to neighboring bodies. In the case of heat produced by intense chemical action, he ascribed the effect to the physical force of a species of molecular friction on the particles acted on. This chem- ical force is capable of transfer by the voltaic battery, and the calorific force moves with it. It has been proved, by experiment on -a com- pound wire of silver and platinum, that, in proportion to the increase of conducting power, ignition is diminished. Mr. Grove here re- ferred to recent researches of his own, to prove that this calorific force was affected by external causes. The same current was sent through two coils of fine platinum wire, one of which was surrounded by an atmosphere of air, the other by an atmosphere of hydrogen, when it was found that the wire in air became white-hot, while that in hydro- gen was not heated. This phenomenon he ascribed either to the mo- bility of the particles of the hydrogen, or to the vibrations moving away from the vibrating surface, or to the state of the surface itself, hydrogen being, as to radiating power, to air, as the color black is to white. That this cooling does not depend on rarefaction, is proved by the intense heat and light produced in vacua. Mr. Grove then called the attention of the Institution to a remarkable experiment lately performed by him, with a battery of 500 cells ; of the two platinum poles, the positive was placed under water, the negative held over it, when a cone of flame issued from the surface of the water towards the negative pole, on the extremity of which a small globule was formed, which fell off as soon as the current was suspended. These facts may serve to explain more clearly the phenomena of the voltaic arc. Mr. Grove exhibited paper on which the strong disruptive effect of the electric battery had dispersed metallic wires, and he showed that these explosions had always occurred in a line transverse to that of the current. He inferred that when ignition commenced in the wire, its molecules assumed a transverse polar direction. When platinum is ignited under circumstances which admit of the effects being accurately noticed, it contracts, swells, and breaks, and a lead wire, similarly acted on, becomes divided by a series of transverse facets. In conclusion, Mr. Grove adverted to recent endeavors to obtain voltaic light for practical purposes. He stated that recent cal- culations led him to believe that for some purposes, such as the illu- mination of light-houses, especially where an intermittent light was wanted, and of the interior of large buildings, it might possibly be adopted at no very remote period. The light of 1,440 candles might be obtained at about four shillings per hour; but this concentrated light is not applicable for streets. The whole subject, however, is beset by many mechanical difficulties. London Athenaeum, March. THE VELOCITY OF ELECTRICAL WAVES. IT is well known that for the past two or three years the electric telegraph has been employed for the purpose of" ascertaining the longitude of various places in this country, which has thus been done 10 110 ANNUAL OF SCIENTIFIC DISCOVERY. much more accurately than it could be by any other method. But in determining the longitude, it becomes a matter of importance to ascer- tain whether the current does really pass over the wires in a time im- measurably small, as has been commonly stated. The longitude, it is well known, is determined by the difference in the time of the transit of any star at the two places, and as soon as it is observed at one place, the observer, by touching a key, records the fact at the other, by means of an astronomical clock ; bnt if any measurable time is consumed in the passage of the current which causes this record, it must be taken into the account. This subject first attracted the at- tention of Mr. Walker, of Washington, while ascertaining the longi- tudes of Cambridge and Philadelphia, and he then became convinced that the time required by the galvanic stream is by no means immeas- urably small, but can be determined, and amounts, between Cam- bridge and Philadelphia, to nearly one twentieth of a second, being, therefore, very much greater than would have been expected from analogy, after Wheatstone's measurement of the velocity of propaga- tion for friction-electricity. Mr. Walker deduces this value from all the comparisons which were made between the three stations, Cam- bridge, Philadelphia, and New York, and thus finds from 18 equations of condition, that the galvanic current would traverse 18,700 miles in a second. This value is determined to within about 1,000 miles, or / 8 . This beautiful result is, in its scientific relations, the more interest- ing from the fact that the galvanic current here traverses different mediums, the conducting wire (iron), three batteries, and the earth, a total length of 1,050 miles. It is particularly striking that the velocity of the galvanic current is so much less than that of fric- tion-electricity, according to Wheatstone's observations. Having formed this opinion, Mr. Walker, of course, felt anxious to verify it, and for this purpose has been engaged in some experiments between Washington and Cincinnati, which are described by Professor Mitchell, in a recent letter. He says, "The principle employed is very simple, and may be easily understood by those not familiar with the subject. Suppose it possible to start two clocks to beating at the same absolute moment of time in Washington and Cincinnati, and that these beats are both recorded at each station. The Cincinnati clock- beat recorded in Cincinnati by a current of electricity having no distance to go is done instantly, while the Washington clock-beat, being re- corded by a current corning from Washington (in case this current should require, say, one tenth of a second of time to pass from Wash- ington to Cincinnati), will fall behind the Cincinnati clock-beat, on the record, by that time, or by one tenth of a second. The reverse is true on the record in Washington. There it is manifest that the Washington clock-beat precedes the Cincinnati clock-beat, in case there be wave-time, and a comparison of the two records (in case no modifying circumstances come in) would show the wave-time, should any exist." In a recent article in the Astronomical Journal, Professor Mitchell gives a detailed account of some of his experiments with reference to NATURAL PHILOSOPHY. Ill this question, and shows that " the velocity deduced along the wires, in case the circuit is 607 miles long, is 28,524 miles per second." He adds, "I place great confidence in these results, as every care was taken to eliminate all possible sources of error." THE PROPAGATION OF ELECTRICITY IN GASEOUS BODIES. IN a paper read before the French Academy, at its sitting on April 16th, M. Matteucci, after noticing some of his former experiments, says, " Since my first experiments, I have found that the law given by Coulomb, for the loss of electricity in moist air, does not hold en- tirely true for dry gases, and that in experimenting on these, the results cannot be compared together, unless the experiments are made at the same or nearly the same, temperature. It is known that Cou- lomb found that the loss of electricity in the same conditions of the atmosphere is proportionate to its intensity, so that the relation be- tween them is constant. The dhTerence between my results and those of Coulomb is, that the number which represents the relation between the electric force lost in a minute and the mean force, is much smaller than that given by Coulomb, and that it varies with the distance at which the electric balls are kept ; and for each experiment made at a given distance between them, the fraction which gives the relation mentioned above increases as the electric charge diminishes. So that in air, in hydrogen gas, or in carbonic acid, when dry, the loss of electricity is not proportioned to its intensity, as Coulomb asserted." He concludes by saying, " We must admit that the gaseous mole- cules are attracted by the electrified bodies, and remain attached to these bodies, attracting other gaseous molecules around them, so as to propagate electricity as in solid bodies." THE CONDUCTING- POWER OF LTQUTDS WITH REFERENCE TO ELECTRICITY. THE conducting power of liquids varies with the temperature, but in a proportion inverse to that in metallic wires, that is, it increases with the rise of temperature. The fact has long been known, but hitherto measurements were wanting. Edmund Becquerel concludes from his experiments on this subject, which, however, are not very numerous, that the increase of the conducting power proceeds propor- tionally to that of the temperature. This assumption must, how- ever, be regarded as a rude approximation to the truth. From a more detailed, though still unfinished investigation of Hankel, we learn that the conduction-resistance of liquids is very sensibly diminished by warming, but that this diminution is not proportional to the change of tempi- rat ure, but is greater for a given difference of temperature the nearer this approaches to zero. The various liquids appear to corre- spond tolerably in these variations, and only differ from one another in this, that those solutions which contain a larger quantity of salts suffer greater variation in their conducting power for the same differences of temperature. It is singular, that the conductivity of a concentrated 112 ANNUAL OF SCIENTIFIC DISCOVERY. solution of sulphate of zinc, as well as of concentrated sulphuric acid, is increased by a moderate addition of water, but again reduced by greater dilution. Liebig's Annual Report. The researches of Professor Horsford, on the conducting power of liquids, made contemporaneously with those of Becquerel, and publish- ed some years since, have furnished many important facts on this interesting subject. Editors. CONDUCTING POWER OF FLAME. IT has been long known that flame possesses a property subversive of electricity, but with respect to the cause of this behaviour, the labors of distinguished investigators, for upwards of one hundred years, have only established thus much, that flame possesses a very strong conducting power for electricity, which can neither be explain- ed merely by the rise of temperature of the air, nor by any conduct- ing property of the aqueous vapor, contained in the hot air of the flame, nor by a current of air, or a removal of electricity by the vola- tile particles that rise from the flame ; for not one of these influences, by itself, evinces the conducting power in so high a degree as flame. However, Volta made use of the flame of a lamp to draw electricity from the air and collect it in his condenser. A few years since, Riess observed that the action of flame extends over much greater distances than docs the upward current of hot air, or than this could make the air conductive ; and that this current does not move at all. From this he concluded that the flame acts not only by direct com- munication, but also by induction (influence), and hence he endeavour- ed to reduce the effect of flame to that of points. He started from the consideration, that the current of hot gas ascending from the flame, and conducting the electricity, was repeatedly cut into and di- vided by the cold air, (which does not conduct electricity) streaming upon and penetrating it, so that there are formed points and threads, as it were, of the conducting gas, which become more and more at- tenuated, and are gradually dispersed through the air, under the influ- ence of the colder surrounding medium. These serrations and points now exert their powerful influence in inducing electricity in all direc- tions, and to considerable distances, producing by these means the effects of good conductors. The action of points is also exhibited by substances that do not burn with flame, but merely smoulder, as tinder, slow-match, &c. Riess, however, proves that in this case, when they cannot be caused by the ascent of incandescent gases, they originate in the combustion of the surface of the body itself. These views involved Riess in a long scientific dispute, in which he has increased the probability of his explanation. Liebig's Annual Report. USE OF GUTTA-PERCHA IN ELECTRICAL INSULATION. DR. FARADAY, in a letter to Mr. R. Phillips, one of the editors of the Philosophical Magazine, states that he has lately found gutta- NATURAL 1'HILOSOPHY. 113 percha very useful in electrical experiments. Its use depends upon the high insulating- power which it possesses under ordinary condi- tions, and the manner in \vhich it keeps this power in states of the atmosphere which make the surface of glass a good conductor. All gutta-percha is not, however, equally good, as it comes from the manufacturer's hands ; but it does not seem difficult to bring it into the best state. A good piece of gutta-percha will insulate as well as an equal piece of shell-lac, whether it be in the form of a sheet, or rod, or filament; but being tough and flexible when cold, as well as soft when hot, it will serve better than shell-lac in many cases where the brittleness of the latter is an inconvenience. Thus it makes very good handles for carriers of electricity in experi- ments on induction, not being liable to fracture ; in the form of a thin band, or string, it makes an excellent insulating suspender ; a piece of it in sheet makes a most convenient insulating basis for any thing placed on it. It forms excellent insulating plugs for the stems of gold-leaf electrometers when they pass through sheltering tubes, and larger plugs supply good insulating feet for extemporary electrical ar- rangements. Cylinders of it, half an inch or more in diameter, have great stiffness, and form excellent insulating pillars. In these, and in many other ways, its power as an insulator may be useful. Because of its o-ood insulation, it is also an excellent substance for ^j * the excitement of negative electricity. It is hardly possible to take one of the soles sold by the shoemaker out of paper, or into the hand, without exciting it to such a degree as to open the leaves of an elec- trometer, one or more inches ; or if it be unelectrified, the slightest pas- sage over the hand or face, the clothes, or almost any other substance, gives it an electric state. Some of the gutta-percha is sold in very thin sheets, resembling in general appearance oiled silk ; and if a strip of this be drawn through the fingers, it is so electric as to adhere to the hand or attract pieces of paper. The appearance is such as to suggest the making a thicker sheet of the substance into a plate elec- trical machine, for the production of negative electricity. Then, as to inductive action through the substance, a sheet of it is soon converted into an excellent electrophorus ; or it may be coated and used in place of a Ley den jar ; or in many of the other forms of apparatus dependent on inductive action. With respect to that gutta-percha which is not in good electrical condition (and which has constituted about one-half of that which, being obtained at the shops, has passed through Dr. Faraday's hands), it has either discharged an electrometer, as a piece of wood or paper would do, or it has made it collapse greatly by touching, yet has on its removal been followed by a full opening of the leaves again. The latter effect Dr. Faraday has traced and referred to a conducting por- tion within the mass, covered by a thin external non-conducting coat. When a piece which insulates well is cut, the surface exposed has a resinous lustre, and a compact character that is very distinctive ; whilst that which conducts has not the same degree of lustre, appears less translucent, and has more the aspect of a turbid solution solidified. Both moist steam-heat and water-baths are believed to be used in its 114 ANNUAL OF SCIENTIFIC DISCOVERY. preparation for commerce, and the difference of specimens depends probably upon the manner in which these are applied, and followed by the after-process of rolling between hot cylinders. However if a portion of that which conducts be warmed in a current of warm air, as over the glass of a low gas-flame, and be stretched, doubled up, and kneaded for some time between the tingers, as if with the inten- tion of dissipating the moisture within, it becomes as good an insu- lator as the best. Dr. Faraday soaked a good piece in water for an hour, and on tak- ing it out, wiping it, and exposing it to the air for a minute or two, found it insulated as well as ever. Another piece was soaked for four days, and then wiped and tried : at first it was found lowered in insu- lating power, but after twelve hours' exposure to the air, under com- mon circumstances, it was as good as ever. A week's exposure in a warm-air cupboard of a piece that did not insulate, made it much better. A film on the outside became non-conducting; but if two fresh surfaces were exposed by cutting, and these were brought into contact with the electrometer and the finger, the inside portion was still found to conduct. If the gutta-percha, in either the good or the bad condition (as to elec- trical service), be submitted to a gradually increasing temperature, at about 350 or 380, it gives off a considerable portion of water; being then cooled, the substance which remains has the general properties of gutta-percha, and insulates well. The original gum is probably complicated, being a mixture of several things; and whether the water has existed in the substance as a hydrate, or is the result of a deeper change of one part or another of the gum, Dr. Faraday is not prepared to say. ELECTRICITY OF THE HUMAN FRAME. AT a meeting of the Paris Academy of Sciences. May 21st, M. de Humboldt sent an extract of a letter, in which M. Emile du Boys- Reyniond describes summarily an experiment, which consists in causing the deviation of the needle of a galvanometer by the effect of muscular action. He takes a very sensitive galvanometer, and fixes at its extremities two slips of perfectly homogeneous platina these two slips he plunges into two vessels filled with salt water, and introduces into them two corresponding fingers of his two hands. At the first immersion of the fingers a more or less decided devi- ation of the needle is always produced, the direction of which fol- lows no law, and which is probably due, at least in part, to some heterogeneousness of the skin of the fingers. When there is a wound on one of the fingers the deviation is stronger, and is always directed in such a way as to show that the wounded finger behaves as the zinc of a zinc-copper couple, supposed to be between the vessels, in place of the body. Of course this is not the kind of action we are concerned with now ; on the contrary, in order to observe the effects announced, we must wait either until the needle has returned to the zero of the scale, or until it has taken a steady position under the con- NATURAL PHILOSOPHY. 115 trol of the remainder of a current, that cannot be overcome. When this moment has come, he strains all the muscles of one arm, so as to establish an equilibrium between the flexors and extensors of all the joints of the arm. At once the needle moves, and the direction of the movement is such as to indicate in the stiffened arm, an inverse cur- rent, according to the notation of Nobili ; that is, a current directed from the hand to the shoulder. When the experiment is made with the galvanometer by M. Reymond himself, the deflection amounts to 30. He obtains, however, movements in the needle of far greater extent by contracting alternately the muscles, first of one arm and then of the other, in time with the oscillations of the needle. On bracing simultaneously the muscles of both arms, very small devi- ations are observable, sometimes in one direction, and sometimes in another ; and these minute deflections are evidently caused by the difference between the contractile force of the two limbs. Hence it arises, that when the experiment is repeated many times successively, the results diminish gradually in amount. The amount of deviation depends upon the amount of the development and the exercise of the muscles. The habitual superiority of the right hand over the left, in this experiment, is to be interpreted by the preponderance of the amount of deflection produced by the tension of the ri^ht arm. M. j de Humboldt says, " The fact of the experiment affecting a mag- netic needle by the alternate tension of the muscles of the two arms, an effect due to volition, is established beyond the shadow of a doubt. Notwithstanding my advanced years and the little strength that I have in my arms, the deflections of* the needle were very con- siderable." To facilitate the experiment, it is advisable to plunge the forefingers into the water, and to support the palms of the hands, to enable one to brace up well the muscles of the arm, which it is purposed to bring into play. Since the announcement of these experiments, many persons have tried similar ones, and only in a single case that of M. Becquerel have we seen any failure noticed. ANIMAL ELECTRICITY. MR. ALFRED SMEE, an English surgeon, and the inventor of the battery which bears his name, announces some important discoveries in animal electricity. By a test which he calls electro-voltaic, he has discovered that the terminations of the sensor nerves are positive poles of a voltaic circuit, while the muscular substance is the negative pole. The sensor nerves are the telegraphs which carry the sensa- tion to the brain, and the motor nerves cany back the volition to the muscles. The brain he infers to consist of five distinct voltaic circles, which, upon theoretical grounds, he believes to be sufficient to account for all the mental phenomena. He has succeeded in mak- ing artificial electric fish, and artificial muscular substance. Should these researches be fully confirmed by other investigators, they must be regarded as affording the most important physiological discovery of the age. 116 ANNUAL OF SCIENTIFIC DISCOVERY. FURTHER RESEARCHES ON ELECTRO-PHYSIOLOGY. WE translate from the Comptes Rendus the substance of a paper by M. Matteucci, on electro-physiology. He commences by recapitulating the four principal points from which he started, and which, in some de- gree, form a summary of his former labors. " 1. In each cell of the electric organ of fishes, the two electricities become separated under the influ- ence of the nervous activity propagated from the brain towards the ex- tremities of the nerves. A relation exists between the direction and the intensity of the nervous current, and the position and the quantity of the two electricities developed in the cell. 2. It has been shown by experiment that the greatest analogy exists between the discharge of electric fishes and muscular contraction! There is no circumstance which modifies one of these phenomena, that does not equally act upon the other. 3. The contraction of a muscle develops in a nerve which is in contact with it the cause by which the nerve excites contractions in the nerves throughout which it ramifies. Analogy leads us to consider this phenomenon a proof of an electric discharge developed by muscular contraction, though this has not been decided by experiment. 4. The electric current modifies the excitability of the nerve according to its direction : when propagated in the direction of. the ramification of the nerve, it destroys its excitability ; but when propagated in a contrary direction, it augments it. I shall now confine myself to communicating a result which I regard as fundamental to the theory of electro-physio- logical phenomena. By a *simple experiment, I have shown that an electric current which traverses a muscular mass in the direction of its fibres, develops in these filaments a nervous current, which direction varies according to that of an electric current, relatively to the ramifica- tion of the nerve. This is the reaction of electricity upon the nervous force. In discovering a new and very intimate analogy between the electric discharges of fishes and muscular contraction, I have shown that the nervous current develops the two electricities in a determinate direction, according to its own direction. In a muscular mass, the two electric states, diffused through the elements of its fibres, produce a current, whose direction varying with that of the electric current is es- tablished, like the direction of the discharge in the torpedo fish, by that of the nervous current which excites it. This foundation of the electro- physiological phenomena I have taken great pains to establish. What- ever may be the nature of the nervous force, it is a fact that this force is propagated in the nerves, sometimes from the brain to the extremities, and sometimes in a contrary direction. It is probable, that when the muscles are contracted by our will, a nervous current is propagated in the direction of the ramification of the nerve ; but on the other hand, the nervous current follows an opposite direction when sensation is ex- perienced by the stimulation of the extremities of the nerve. " I have shown n my former researches, by experiments, the great difference between the nervous and the muscular substance, as re- gards the conduction of the electric current. These experiments I NATURAL PHILOSOPHY. 117 cannot repeat, but will confine myself to one, which may be applied to the case in point. This experiment consists in introducing the nerve of a sensitive galvanoscopic frog into the interior of a muscular mass, cut in the direction of its fibres. On passing a tolerably strong electric current through this mass, contractions lire never excited in the prepared frog. It is then proved that, when a muscular mass is trav- ersed by an electric current, the nervous filaments diffused through the mass do not produce any sensible part of this current, so that the effects obtained can be due only to the direct action of the electric current upon the muscular fibre, and to the indirect action or the influence of the electric current upon the nervous force. The follow- ing are these effects. If, in a living rabbit, dog, or frog, we expose the muscles of the legs, and pass an electric current from a pile of thirty or forty elements through the muscles, applying one of the poles to the upper and the other to the lower part of the leg, if the posi- tive pole is placed above and the negative one below, so that the electric current traverses the muscular substance in the direction of the ramification of the nerves, a very powerful contraction is pro- duced, not only in the muscles of the leg, but also in those of the foot. " These results can be explained in but one way. The very power- ful contraction excited by the electric current proves the existence of a nervous current passing from the extremities towards the centre, and developed under the influence of an electric current which trav- erses the muscular mass in the contrary direction to that of the ramification of the nerve. These conclusions have an important con- nection with the law of electric discharges in fishes, which arise from the production of a nervous current by the stimulation of the nerve, which is distributed in the organ. But in the experiments described, a nervous current is produced by the electric discharge passing through the muscle. In the discharge of the torpedo, therefore, the electric states are produced by the animal, while in the experiment the nervous current is produced by the influence of the electric current" CURIOUS ELECTRICAL PHENOMENON. WE learn from a letter from a gentleman connected with the Bay- State Mills, at Lawrence, Mass., some facts with reference to a new and curious application of electricity which has been introduced into those mills. The electricity is generated by the motion of the ma- chinery, and is employed for lighting up the gas-burners. It exists in large quantities in the card-rooms, where there are many belts rim- niiig on iron pulleys, and, in the cold dry atmosphere of winter, often produces serious damage to the quality of the carding. The manner in which it was discovered that this electricity could be applied to ' li^lilinir up," is somewhat curious. When the gas was first let into the pipes in the mills, one of the overseers discovered fire jetting out from one of the pipes near a belt, and on examination it was ascertained tiiat a small stream of gas was escaping. It was surmised that it had been ignited by the electricity, and to prove it. an expert- 118 ANNUAL OF SCIENTIFIC DISCOVERY. ment was tried. Near a large belt in the carding-room was a gas- burner, and on a bench between them there was placed a small quan- tity of wool, which is a non-conductor of electricity. If a person stood upon this wool, reaching one hand within two or three inches of the belt, and touching the gas-burner with one finger of the other, the escaping gas was at once ignited with an explosion like that of a per- cussion cap, the body of the operator thus being made the medium for conducting the electricity. The writer adds," We shall be able to make a great saving of expense in the woollen manufacture as soon as we can discover an effective method of conducting the electricity away from the cards, as we shall then be able to dispense entirely with the use of oil on the wool, which will save at least $30,000 per annum, when the mills are in full operation." Editors. ON THE PRODUCTION OF LIGHTNING BY RAIN. WE find, in Brewster's Magazine for Sept., a paper communicated by W. R. Birt, on the production of lightning by rain. The authors atten- tion was attracted to this subject by a question put in the report of the Committee on Physics of the Royal Society, who say, " There is one point to which we wish that some attention might be paid : it is the sudden gush of rain which is almost sure to succeed a violent detonation immediately overhead. Is this rain a cause or consequence of the electric discharge 1 We are not aware that the former view has ever been maintained or even suggested. Yet it is very defensible. In the sudden ^ o / agglomeration of many minute and feebly electrified globules into one rain-drop, the quantity of the electricity is increased in a greater propor- tion than the surface over which (according to the laws of electric distri- bution) it is spread. Its tension, therefore, is increased, and may attain the point when it is capable of separating from the drop to seek the sur- face of the cloud, or of the newly formed descending body of rain, which, under such circumstances, and with respect to electricity of such a tension, may be regarded as a conducting medium. Arrived at this surface, the tension, for the same reason, becomes enormous, and a flash escapes." As we have said, Mr. Birt was induced by this paragraph to commence some observations on the fall of rain during thunderstorms, and his first opportunity was on July 25th, when, during a thunderstorm, a sudden gush of heavy rain occurred, which, within two seconds, was succeeded by a vivid flash of light- ning, and the thunder of course followed this. On the 26th, he had several opportunities of noticing, as there were a number of showers during the day, and on every occasion he is quite certain that the sudden gush of rain preceded the electric discharge. The storm of the 26th was a very severe one, and several houses were struck in the immediate vicinity of the writer's residence at Bethnal Green. He is of the opinion that, as is suggested in the passage quoted above, an agglomeration of the smaller drops took place, increasing the electric tension to such an enormous extent, that a flash escaped in the imme- diate neighbourhood of the houses struck, and thus entered them. NATURAL PHILOSOPHY. ] 19 This country affords much better opportunities than Great Britain for observing the phenomena connected with thunderstorms, on ac- count of their greater frequency and severity, and it is therefore to be desired that some of our scientific men should commence a series of observations with a view of ascertaining whether rain is really the cause of lightning. CONNECTION OF THE AURORA BOREALIS WITH ELECTRICITY. THE connection of the aurora borealis with electricity, a fact which has been taken for granted since the days of Franklin, has only lately been fully established. Mr. E. C. Herrick, of New Haven, has recently observed an electrical action on the wires of the telegraph at that place during the occurrence of an aurora. The same fact has been also noticed in England and on the Continent during the last year. During the aurora of the 17th of November, 1848, the tele- graph at Watford, England, was violently affected for many hours. On several occasions the electric current passing was sufficiently powerful to attract the movable armature of the stationary electro-magnet of a bell apparatus, so as to allow the alarm to be sounded. To effect this, the pressure of one third of an ounce was found by experiment to be necessary, and from a calculation based on the length and thick- ness of the wires, it is supposed that the power of an aurora, if sim- ilarly extended over a square mile of surface, would be equivalent to the lifting of seventy-five tons. It has not been fully ascertained, whether the action is one of actual transfer of electricity from the space at one end of the wire to that at the other, whether it is an inductive action of the aurora at a distance, disturbing for an instant the electrical equilibrium of the wire. A NEW MODE OF DISCHARGING A LEYDEN BATTERY. WE find in the London Mechanic's Magazine a notice of a novel method of discharging a Leyden battery, which has lately been ex- hibited before the Polytechnic Institution. In this new method the jars are . arranged in a series, with the knob of each in connection with the outer coating of the next in the series, as has often been done heretofore in the process of charging them. In our case, how- ever, they are charged separately, or are first connected together in a battery in the ordinary way. When ready to be discharged, they are by a simple movement all insulated and arranged in a series as described above, which may be made to take a semicircular or U form, in order to bring the knob of the last jar in the series into convenient proximity to the outer coating of the first jar. The effect of this ar- rangement is to multiply the intensity in a manner analogous to that of the galvanic battery, so that if the outer coating of the first jar be supposed to be in connection with the earth, and the number of jars be twelve, the knob of the last jar will be twelve times more highly electrified than the knob of either jar was before being thrown into the series. The disruptive or space-penetrating force is consequently 120 ANNUAL OF SCIENTIFIC DISCOVERY. greatly increased, and a battery of twelve large jars is said to have been discharged through a space of about three feet. The quantity of the spark, however, is only that of a single jar, and therefore, to pursue experiments satisfactorily, large jars must be used, with an abundant source of electricity from a powerful machine. In order to make the change in the arrangement of the jars, each jar is support- ed in a horizontal position on a vertical spindle, and a slight turn giv- en to each spindle at once brings them from the position they are placed in for charging into the series described. ELECTRIC BATTERIES. DISCOVERY IN PLATING. AT the late meeting of the British Association Mr. W. S. Ward produced a paper on this subject, and stated that a series of calcula- tions, founded on data, produced to the Chemical Section at Swansea, showed the efficient power of three generally useful forms of battery, known as Smee's, Daniell's, arid Grove's, would be equal when 100 pairs of Smee's, 55 pairs of Daniell's, or 34 pairs of Grove's were used, and that the expense of working such batteries, as regards a standard of 60 grains of zinc in each cell per hour, would be about 6d., l^d., and 8d., respectively. This communication led to some conversation on the economy of the various batteries, and the processes for plating; in the course of which Mr. Shaw and Dr. Percy instanced the magneto-electric ma- chines which are employed at Birmingham for electro-plating, in which the current cost of the motive power viz. a steam-engine to put the magneto-electric machine in action was the only working- cost. Mr. Elkington stated that they had never been induced to abandon the voltaic battery which they employed in their manufactory, finding it more economical than the magneto-electrical machine, of which he was the patentee. He also stated the remarkable fact, that a few drops of the sulphuret of carbon, added to the cyanide of silver, in the decomposing cell, has the property of precipitating the silver perfectly bright, instead of being granulated so dead as it is when thrown down from the solutions ordinarily employed. London Aihe- n&um, Sept. INGENIOUS APPLICATION OF ELECTRICITY. THE London Athenaum furnishes the following ingenious applica- tion of electricity, by means of which signals are given that indicate the pressure of steam in the boiler of an engine. The invention is by Mr. Arthur Dunn. " Tubes being filled with mercury are made part of a galvanic circuit, and connected with bells as the mercury rises from increasing pressure in the boiler ; the circuit is thus com- pleted, and the bells respectively rung indicate the amount of pres- sure. In this way attention is called to the condition of the steam the moment it exceeds its ordinary and safe working condition." NATTKAL PHILOSOPHV. 121 DR. LOCKERS ELECTRO-CHRONOGRAPH. IT is well known that Congress at its last session appropriated $10,000 to be paid to Dr. Locke for one of his electro-chronographs, to be erected by him at the National Observatory in Washington. This instrument has now been finished in Boston and forwarded to its destination. Much curiosity has been excited in regard to this impor- tant invention, and we have compiled from a great variety of sources a description, which it is hoped will serve to convey some idea of the working and purpose of the electro-chronograph. The object of this instrument is for the determination of the exact period, to the hundredth or even the thousandth part of a second, of a transit or other astronomical observation by which longitude may be ascertained. The difference of longitude of any two places, it is well known, is determined by observing the period of the occurrence of certain celestial phenomena, such as eclipses, transits, occupations, &c. In order to insure perfect accuracy, the utmost exactitude in regard to time, even to the fractional part of a second, is desirable. The usual practice has heretofore been for the observer to note the exact time of the transit or other phenomena by listening to the beats of a clock or chronometer, and estimating the fraction of a second be- tween two beats when the event occurs. This requires a nicety of hearing only attained by long practice, and when attained, still far from being a perfect measure of time. By the invention of Dr. Locke, the observer can record the exact time on a fillet of paper, without taking his eye from the telescope. The instrument of Dr. Locke, which he has termed an Electro- Chronograph, is a combination of the magnetic clock, Morse's tele- graphic register, and a break-circuit key, or instrument for interrupt- ing the magnetic circuit. The first, or magnetic clock, was invented in England, by Mr. Wheatstone, about the year 1841. An invention of a similar character was also made by Mr. Bond of the Observatory at Cambridge. Its object is to make several clocks on the same tele- graph line, even at a distance of hundreds of miles, mark the same instant of time. This is done by breaking the circuit of the magnet- ic fluid at each second of time. The method of interrupting the cir- cuit in the clock of Dr. Locke is different from that adopted by Wheatstone, and has this advantage that it cannot alter the rate of the most delicate astronomical clock. With this clock is combined a register, by which, instead of the beats of the clock at one extremity of the telegraph line being made audible only, as was contemplated by Wheatstone, they are made xisible as well as audible, by being imprinted on a fillet of paper which revolves around a drum. In the Morse register, when the magnetic circuit is unbroken, a continuous line is made. The magnetic clock of Dr. Locke interrupts the circuit at each second, and produces breaks which represent the second on the fillet of paper at the other end of the line. The dashes or lines between each break are exactly of a length, and each break represents a second. By 11 122 ANNUAL OF SCIENTIFIC DISCOVERY. an ingenious arrangement of the machinery, the end of each minute, of each five minutes, and of each hour, is represented, so that the exact period when an observation is made may be determined without counting the seconds. The beginning of a minute is recorded by the omission of a break between two seconds, when the confluent lines extend, say an inch. The commencement of an hour is indicated by a line of double the length of the five-minute line. The remaining* part of this chronograph is the break-circuit key, by which the period when an observation is made is determined. The astronomer at any station on a line of several thousand miles in length, may imprint on the register the date of any event by simply tapping, after the manner of playing upon a piano, upon a break-circuit key. This imprints in the indented line a corresponding break-circuit space. Two or three spaces may be printed in one second, if desired. Two seconds of time is ample for the equatorial interval of the wires of a transit instrument. The net-work of spider lines is divided into some nine or more tallies, or distinct groups of five wires each. All these tallies in the case of the transit of a star are imprinted on the register, in the time occupied by the ordinary method for a single tally, to which a transit has been usually limited. The skill required for tap- ping on the key at the instant of the bisection of a star is easily ac- quired, and the accuracy of each imprint is much greater than that of a single record by the common method. The imprints furnish a per- petual record of the date of the event, and may be read off with great rapidity to the hundredth of a second, by means of a graduated scale of the paper used for registering. Those who understand the general principles of the magnetic tele- graph will readily comprehend the main principles of this invention. The value of it can only be estimated by the astronomer. In deter- mining longitude, the observations of many nights, even for years, have heretofore been necessary in order to secure accuracy. With one of the clocks of Dr. Locke, the difference of longitude between the National Observatory at Washington and any other point reached by magnetic telegraph may be determined in one night so closely as to show in what part of the building the observations were made. Lieut. Maury, in a letter to the Navy Department, after describing the instrument, says : "Its powers are such that the astronomer in New Orleans, St. Louis, Boston, and every other place to which the magnetic telegraph reaches, may make his observations, and at the same moment cause this clock, here in Washington, to record the instant with wonderful precision. Thus, the astronomer in Boston observes the transit of a star as it flits through the field of his instru- ment and crosses the meridian of that place. Instead of looking at a clock before him, and noting the time in the usual way, he touches a key, and the clock here subdivides his seconds to the minutest frac- tion, and records the time with unerring accuracy. The astronomer in Washington waits for the same star to cross his meridian, and, as it does, Dr. Locke's magnetic clock is again touched ; it divides the seconds and records the time for him with equal precision. The dif- ference between these two times is the longitude of Boston from the NATURAL PHILOSOPHY. 123 meridian of Washington. The astronomer in New Orleans, and St. Louis, and every other place within the reach of the magnetic wires, may wait for the same star, and, as it comes to their meridian, they h-ivc but to touch the key, and straightway this central magnetic clock tells their longitude. " And thus this problem, which has vexed astronomers and naviga- tors, and perplexed the world for ages, is reduced at once, by Ameri- can ingenuity, to a form and method the most simple and accurate. While the process is so much simplified, the results are greatly re- fined. In one night the longitude may now be determined ivith far more accuracy by means of the magnetic telegraph and clock than it can by years of observation according to any other method that has eier been In a later letter Lieut. Maury says: " The magnetic telegraph now extends through all the States of the Union, except, perhaps, Arkansas, Texas, and on the frontier ; so that a splendid field is presented for doing the world a service by connecting, for difference of longi'.ude through means of the magnetic telegraph and clock, all the principal points of this country with this Observatory (Washington). In antici- pation of such extension of the wires, I ordered an instrument for the purpose, and it has recently arrived. It is intended to determine latitude also, so that by its means and this clock I hope, during the year, to know pretty accurately the geographical position of Montreal, Boston, Chicago, St. Louis, New Orleans, &e., and their difference of longitude from this place, quite as correctly as the difference between Greenwich and Paris has been established by the usual method and after many years of observation." THE COPYING ELECTRO-TELEGRAPH. THE specification of the invention, by means of which a letter written in London may be copied lerbalim et literatim in Liverpool, discloses the means by which this is to be accomplished. Wonderful as it seems, to have the power of producing a fac-simile of writing in- stantaneously at any distance, the mode of operation is extremely simple. The writing materials consist of tinfoil, varnish, and a quill pen. The letter thus written is applied to a cylinder; a metal style or point presses on the writing as the cylinder revolves ; and the point being attached to a screw, it moves gradually along from one end of the cylinder to the other. The thread of the screw is sufficiently fine for the point to traverse six or seven times over each line of writing before it passes by the revolution of the cylinder to the next. The point is connected with one pole of a voltaic battery, and the cylinder is connected with the other pole, so that the electric current may pass from the former to the latter : but as varnish is a non-conductor of electricity, the circuit is interrupted whenever the point presses on the varnish-writing. The distant telegraphic instru- ment is an exact counterpart of the one that transmits ; but, in place of the tinfoil, paper, moistened with a solution readily decomposed by electricity, is applied to the cylinder. Thus the electric current trans- 124 ANNUAL OF SCIENTIFIC DISCOVERY. initted through the ordinary telegraphic wires is made to pass from the metal points to the cylinders of the two instruments, through the interposed moistened paper on one, and through the tinfoil on the other. When the metal point of the transmitting instrument is press- ing on the bare tinfoil, the electric circuit is completed through the paper on the distant cylinder, and by the decomposition of the solu- tion a mark is made; when the point is pressing on the varnish, the circuit is interrupted and the marking ceases. In this manner, the point of the transmitting instrument, by passing several times over each line in different parts from the top to the bottom, produces an exact copy of the forms of the letters; the writing appearing pale- colored on a dark blue ground, consisting of numerous lines made spirally round the cylinder. It is essential to the correct working of the instruments that they should rotate exactly together, and this Mr. Bakewell has accomplish- ed by the regulating power of electro-magnets brought into action at regular intervals by means of pendulums. By means of a guide-line the operator at the copying-station can tell with accuracy whether his instrument is moving foster or slower than the other, and thus regu- late the pendulum. Cylinders six inches in diameter may be regula- ted to revolve thirty times in a minute and produce distinct copies of writing. The rate of copying gives 400 letters per minute with a single wire, and with two wires and two points that number would be doubled. London Spectator, June 23. NEW TELEGRAPH. A MR. JOHNSON, of Oswego, has invented a new machine for tele- graphic purposes. The principle of it is new, in the fact that it uses shot, or the dropping of shot, to make marks, indentations, or signs, on a white sheet of paper. The motive-power of electricity, or of magnetism, Mr. Morse does not presume to patent, but he has patent- ed the use of it for making signs, and what we call the power of in- vigorating the current of electricity by relays of batteries. Mr. John- son uses the common motive-power of electricity to drop his shot, but when the shot are dropped, then another very simple arrangement makes with them the mark on the paper. These shot return in an ever- revolving wheel, and thirty of them do all the work. THE COAST SURVEY AND THE MAGNETIC TELEGRAPH. ON the fourth day of the sitting of the American Association at Cambridge, Mr. S. C. Walker, Assistant of the U. S. Coast Survey, at the direction of the Superintendent, communicated the substance of his recent Report on the Experience of the Coast Survey in regard to Telegraphic Operations. We give all that seems important. " The first mention of the electro-magnetic telegraph, in connec- tion with longitude operations, as far as I know, was made, in 1837, by M. Arago to Dr. Morse. The first practical application of the method was by Capt. Wilkes, in 1844, between Washington and Bal- NATURAL PHILOSOPHY. 125 timore. Two chronometers, previously rated by astronomical observa- tions in the vicinity, were brought to the two telegraph offices, and were compared together through the medium of the ear, without coin- cidence of beats. This process is accurate enough for geographical or nautical purposes ; but its precision stops short of the mark where the requirements of geodesy begin. In fact, two clocks beating the same kind of time, when placed side by side, cannot be compared together, by the human ear, with sufficient precision for geodetical purposes. The subsequent experience of the Coast Survey has shown, that where several astronomers make independent comparisons of clocks, in this manner, two seconds of arc, or twelve hundredths of a second of time, is an average discrepancy between their results. " The subject of telegraph operations for longitude had engaged the attention of the Superintendent of the Coast Survey previous to the experiment of Capt. Wilkes; but the orders received by me for this purpose bear date November 24, 1845. In 1846, the very first season in which two astronomical stations of the Survey were brought in connection by the Morse telegraph lines, the work of connecting them together in longitude was commenced in earnest by the Superin- tendent of the Coast Survey. The cooperation of the National Obser- vatory, as one of the stations, was freely tendered by its Superintendent, Lieut. Maury, U. S. N., and accepted by Prof. Bache. Another station was established at Philadelphia, under the superintendence of Prof. Kendall, and still another at Jersey City under Prof. Loomis. " Owing to the imperfect insulation of the lines, the connection of Jersey City with Washington failed that year; but the Washington and Philadelphia stations were connected together astronomically on the 10th and 22d of October. The method of comparison by coinci- dence of beats of solar and sidereal timekeepers, was not introduced this year; but the equivalent one w r as employed, viz., the exchange of star-signals. These are the dates of instants of the passage of a star over the wires of the eye-piece of the transit instrument, signal- ized by tapping on the telegraph key at one station, and recording it on the Morse register at both. "In 1846, we connected together in longitude the Washington and Philadelphia stations. In 1847, the programme left unfinished in 1846, by the imperfection of the lines, was resumed and completed, and Washington, Philadelphia, and Jersey City were connected to- gether. On the 27th July, 1847, the method of coincidence of beats, used so successfully by R. T. Paine, Esq., in the chronometric operations for longitude in Massachusetts, and by Struve and Airy in their chronometric enterprises, was applied to the telegraphic compari- sons of the Philadelphia arid Jersey City clocks. This method of coincidence was used in combination with exchanges of star signals, in the telegraphic operations of the Coast Survey in 1848, when the Cambridge observatory, under Prof. Bond, and the Stuyvesant Station in New York, were connected together by the Coast Survey. "In October, 1848, Cincinnati was connected with Philadelphia. 11* 126 ANNUAL OF SCIENTIFIC DISCOVERY. The labors of the year 1848 comprise some 1,800 observed transits of stars, 800 comparisons of chronometers by coincidences of beats taken at the stations, 5,000 transits over wires, for determining the personal equations of the officers of the Survey, many thousand exchanges of personal clock signals, and 600 star-transit signals. If even this prodigious accumulation of statistics was considered a gain of many fold over the old method of obtaining astronomical longitudes, what shall we say of the automatic process employed in 1849, where one night's exchange of star signals between Philadelphia and the Seaton Station, printed automatically on a single sheet of paper, is worth the whole list of statistics collected by the Coast Survey between Philadelphia and Washington in 1847? "In my report of December 15, 1848, feeling the responsibility under which I acted, I spoke with caution on the subject of the comparative excellence of the automatic printing method; though some of my friends thought that its merits were overrated. I appealed to the ex- periments that were to be made in the campaigns of 1849 for a test of the new method. That which was then anticipation only, is now re- ality ; and I am able to say, from recent trials, between Cambridge and Washington, and between the Seaton Station under my care at Washington, and the stations at Philadelphia, and at Hudson, Ohio, that the excellence of the new method surpasses all that I ventured to hope for in December last. I then ventured 1o claim for the auto- matic printing method a tenfold gain over the old one. I now find that one transit over one wire is worth four wires by the old method, and that ten transits over wires may now be printed, where one was done be- fore ; making a gain by the new or automatic method of some forty fold. I mean by this the gain from multiplication of transit over wires, and superior precision of each. We cannot in one night obtain the advan- tage of the average of the meteorological peculiarities of forty." After enumerating the registers of Morse, of Mitchell, and the chemical method of registering with the main circuit, he says : " The fourth form of the register is Mr. Saxton's invention of this year. It is somewhat on the plan of his celebrated ruling-machine. The cylinder now before the Association contains the culmination of the planet Neptune and the stars near his parallel, printed by me at the Seaton Station, August 11, 1849. It might seem that the subject of the place of the planet Neptune is foreign to the purpose of telegraph operations. Such is not the case ; for we have used this planet as a fundamental star. I take occasion, therefore, to remark, that the ob- servations of the culmination of Neptune on four nights in the month of August at the Seaton Station, by Pourtales and myself, show that my ephenieris, published by Prof. Henry in the Smithsonian Con- tributions to Science, agrees \vith the heavens within half a second of arc. From this close agreement it may be inferred, that, if the Neptune of Prof. Peirce's theory and my elements were conceived to be a planet, placed side by side in the heavens with the true one ever since its discovery, the two would form a double star of an order so close that not even the great Cambridge refractor could detect their duplicity. NATURAL PHILOSOPHY. 127 " An objection has been raised to the Morse registering fillet, that it is too voluminous for the quantity of matter recorded. This objection, and that of expensiveness, apply with more force to the metallic cylin- der, however accurate be its indications. To remedy this evil Mr. Saxton has contrived a sheet of paper which incloses the cylinder and lasts for about two hours of constant work. The sheets and register- ing fillets now submitted for the inspection of the Association con- tain the comparison of the printed record of the culmination of the stars in the Dolphin. The Saxton sheet, the chemical fillet, and the Morse fillet, are triplicate records of the same identical star-signals. The result of the reading, as far as experiments have been made, is, that all kinds of registers at the same place read alike. It is worthy of remark, that these registers contain the printed record of the tran- sits of both components of the double star Gamma Delphini, printed with ease on each of the forty-five wires of the Wurdemann's dia- phragm, making ninety imprints in a culmination. From my experi- ence in printing the transit of this pair of double stars, I am led to the conclusion, that four stars forming a quadruple star, when at prop- er distance, may all be printed at the time of their transit over a dia- phragm of fifty wires, making two hundred imprints for one transit, a rapidity of playing on the key far below that of good execution on the piano. " Of the different kinds of registers I prefer the sheet of Mr. Saxton. One sheet filled on both sides, or two pages, will contain an ordinary night's work. A year's work will make a book of some three hun- dred pages, on the margin of which may be entered the ordinary re- marks for an observing-book, relative to the state of the level and meteorological instruments, name of stars observed, and instrumental deviations. If folded up, or bound and put away for a century, the reduction of the work will then be as easy as at first. In fact, we may, with the metallic cylinder, electrotype the plate ; or, using cop- per, we may print from it without. And, in the case of the paper sheet, instead of Saxton's graver, with Indian ink, we may employ a pen, with lithographic ink, and multiply copies at pleasure, when- ever we choose. When we consider the compactness of the register on Saxton's sheet, we may perhaps find that the publication of transit observations will best be made by the lithographic process, applied to the printed telegraph sheets ; thus giving to the world the printed record with all the accuracy of a Daguerreotype. The registering fillet now exhibited to the Association contains the culmination of both limbs of the moon, printed by myself, on the 3rd of August last, on 35 wires of the diaphragm. By the mean of the results, the probable error of the imprint of a transit of a single limb over a single wire is the six- teenth of a second; whereas, in 1846, with the great Washington Equatorial, and a power of 300, I found that, with the old method, my probable error, by G6 trials, was twice as great, namely, the eighth of a second. Thus it appears that the measure of precision is twice, and the weight four times, as great, in the new method, as in the old. No labor of training for the work is needed. " A hundred wires is a high estimate for a night's work of an obser- 128 ANNUAL OF SCIENTIFIC DISCOVERY. vatory, by the old method. I have printed fifteen hundred wires with- out fatigue, in one night, by the new. Since each wire is worth four of those of the old method, we have six thousand to one hundred, or sixty to one, as the relative efficiencies of the night's observations. " When we reflect that the probable error of one transit over one wire is only the sixteenth of a second, and that with five wires it is only a thirty-sixth part, or three hundredth of a second, it is man- ifest that one tally, or five wires, is ample for all ordinary work. In fact, one wire is sufficient for most of the purposes of astronomy. I have been led, on consideration of all the facts known from the ex- perience of the Coast Survey, to make the following remark relative to the precision of our work, after proper adjustment of the transit instrument, or measurement of its deviations from a normal state : The printed transit of a fundamental star over any one wire of \Vur- demanri's diaphragm, and that of a star, planet, or comet, whose place is sought, over another wire, both reduced to the centre, on the suppo- sition of uniformity of interval, give the place of the object sought with a precision not much below that on which rest the present elements of all the bodies in the solar system" SUBMARINE TELEGRAPH BETWEEN ENGLAND AND FRANCE. A GENTLEMAN by the name of Brett has obtained from the French government the authorization to establish an electric telegraph be- tween Calais and Boulogne, which, crossing the Channel under the water, will go to Dover on the coast of England. The arrangement entered into guarantees certain advantages to the French government, and leaves all the expense to Mr. Brett, securing him, however, a privilege for ten years, in case the experiment should succeed. The work must be terminated by the 1st of September, 1850, at the latest Experiments to test the practicability of effecting an electric com- munication beneath the surface of the ocean, for considerable dis- tances, have recently been made at the harbor of Folkestone, Eng- land. Upwards of two miles of wire, coated with gutta-percha, were submerged in the sea along the mouth of the harbour. One end of the wire was connected with a telegraphic instrument on the deck of a steamer, and the other end with a wire communicating with the Lon- don telegraph. Messages were sent back and forth with no greater difficulty than with the ordinary wires on land. The insulation effect- ed by gutta-percha is, no doubt, most perfect. The experiments of Faraday have shown that it is one of the most perfect electrical insu- lations with which we are acquainted. How far it may be acted upon by the chlorine, iodine, &c., contained in sea waters, is a question which has not yet been solved. The wire used in this experiment was, when covered with gutta- percha, about a quarter of an inch in diameter; but this is much smaller than that which it is proposed to stretch across the Channel. It is believed that the kind of wire proper to be used, is the twisted iron wire, coated so thickly with gutta-percha as to be nearly three quarters of an inch in diameter. In order to guard against interrup- NATURAL PHILOSOPHY. 129 tion, such as would be liable to arise from the fracture of the wire, it is proposed to stretch two or three lines across the Channel, in differ- ent places, at such distances from each other as to render it improb- able that all would be broken the same day. In the event of one being fractured, a repair could be easily effected hi a short time, by means of steamers, kept continually in readines-s on both sides of the Channel, for fishing up and discovering the broken wire. The im- mense business of a line of telegraph between London and Paris would, it is thought, justify a much greater expense than is involved in the arrangement indicated. English Paper. DISCOVERIES IN MAGNETISM. BEETIN, in an examination of the rotation of the plane of polariza- tion by the electro-magnet, or the wire helix, has been the first to establish, under various circumstances, the law, that the rotation is always in the direction of the magnetizing current, or of the currents which, according to Ampere, would be set up, under the influence of the electro-magnet, in a piece of soft iron, placed in the position of the substance employed. It was considered, till lately, as an established fact, that the mag- netism of steel magnets was entirely destroyed by a white heat, and that at this temperature even iron no longer obeyed the attraction of the magnet. Pouillet, indeed, had stated that cobalt remained mag- netic even at a very high temperature, but that, on the contrary, the magnetism of chromium disappeared at a heat somewhat below red- ness, and that of nickel at 350. Recently, however, Faraday has found by experiments with powerful electro-magnets, that even white- hot iron, and nickel heated far above 350, still followed the attrac- tion ; and Pliicker has more closely examined the behaviour of the magnetic and diamagnetic properties under increasing temperature. Faraday considered that it might be concluded from his experi- ments, that by an appropriate mixture of magnetic and diamagnetic substances, a perfectly neutral body might be produced ; Pliicker, however, has been led by his observations to an opposite conclusion. The latter concludes, from a variety of experiments, that the diamag- netism increases more rapidly than the magnetism, with an increasing power in the electro-magnet ; and he considers it to be quite indiffer- ent whether the increase of the intensity arises from the employment of a greater number of cells, or from a closer approximation to the poles. If these results are perfectly accurate, no absolutely neutral body can exist ; for a body which behaves as neutral at any given distance will be magnetic at a greater, diamagnetic at a less distance. Liebig's Annual Report. ACTION OF MAGNETISM ON ALL BODIES. AT the meeting of the Paris Academy of Sciences, on May 21st, M. Edmond Becquerel communicated a paper upon the effects of magnetism upon all bodies. The following are his deductions : 130 ANNUAL OF SCIENTIFIC DISCOVERY. " 1. AH bodies become magnetic, as soft iron does, under the influence of a magnet, but in greater or less degree according to their nature. ^j ' cp Cj O 13. The temporary magnetism of a body does not depend upon its mass, but on the manner in which the ether is distributed in the body. 3. A substance is drawn towards a magnetic centre by the difference of the actions exerted upon the substance and upon the volume of the medium displaced by it." The effects were measured by the tension developed upon small bars of the various substances by an enormous electro-magnet. The continual oscillations are prevented by suspend- ing under each bar a small sphere of lead or zinc, immersed in water or a solution of chloride of calcium. " Measuring, in this way, the actions exerted upon substances mov- ing in different media, I convinced myself of the enormous influence exerted by the surrounding medium. Thus, common glass, which in the air is attracted by the t\vo poles of a magnet, is strongly repelled by these same poles when in solutions of iron or nickel; sulphur and white wax, which in the air are repelled by the centres of magnetic action, are attracted when they are immersed in concentrated solutions of chloride of calcium or chloride of magnesium." Upon the third general law announced above, he says, " Thus, a body is attracted or repelled by a magnetic centre, according as it is immersed in a medium less or more magnetic than itself. Hence it results that the attractions and repulsions exerted upon different bodies by either pole of a magnet near which they are brought, depend upon the same cause, and not upon two orders of phenomena." To explain the fact, that all bodies are not attracted in xacito, and that some substances are almost as much repelled in vacua as in air, " it is necessary to admit that the ethereal medium by means of which magnetic actions are transmitted is influenced in the same way, but in a different degree, in a void space and in one containing matter ; and that a void space be- haves like a medium more magnetic than the substance which is most repelled, that is to say, bismuth. Certain gases, as nitrogen, nitrous oxide, &e., experience no appreciable action from magnetism, but oxygen does, and the slight magnetic power of the air is due solely to the presence of oxygen. I found that a small bar of charcoal, which ha? condensed oxygen, oscillates between the poles of a strong mag- net like a small magnetised bar, whilst in xacuo it is generally repelled, and always feebly influenced, by the action of magnetism." " Comparing the power of oxygen with that of iron, we conclude that 10.78 cubic feet of air has an action represented by 1.65 grain of iron. If we reflect that the earth is surrounded by a mass of air, equal in weight to a stratum of mercury 30.4 inches in depth, it may be asked whether such a mass of magnetic gas does not interfere in the phenomena dependent on terrestrial magnetism, and perhaps in the diurnal variations of the magnetic needle ; and if we calculate the magnetic power of this fluid ma&s, we find it equivalent to an im- mense sheet of iron, rather more than 0.004 of an inch in thickness, and covering the whole surface of the globe." The author concludes by saying, "I do not, therefore, admit any difference between dia- magnetism and magnetism proper." NATURAL PHILOSOPHY. 131 THE MAGNETIC RELATIONS OF THE POSITIVE AND NEGATIVE OPTIC AXES OF CRYSTALS. MR. FARADAY'S discovery of diamagnetic phenomena is likely to lead rapidly to some important knowledge of the molecular forces which determine the conditions of the material creation. Pliicker, of Bonn, in a letter to a friend, says: "I replace the declination-needle by certain crystals suspended horizontally by a fibre of cocoon silk.. They take' under the action of the earth's magnetism, a determinate and fixed direction. I can vary at will, and predict this with certainty ; and obtain crystals to act as needles which shall point constantly to- wards the poles of the earth, towards the magnetic poles, or to- wards some azimuthal point." In a later letter to Dr. Faraday, Pliicker says, " The first and general law I deduced from my last experiments is the following. There will be either repulsion or attraction of the optic axes by the poles of a magnet, according to the crystalline structure of the crystal. If the crystal is a negative one, there will be repulsion ; if it is a positive one, there will be attraction" After some other remarks, he continues, " Cyanite is by far the most interesting crystal I have examined. It points very well to the north by the magnetic power of the earth only. It is a true compass-needle, and more than that, you may obtain its declination. The crystal does not point according to the magnetism of its substance, but only in obedience to the magnetic action upon its optical axes. If you approach to the north end of the suspended crystal the south pole of a permanent magnetic bar, strong enough to overpower the magnetism of the earth, the axis of the prism will make with the axis of the bar an angle exactly the same as it made before with the meridian plane, the crystal being directed either more towards the east, or more towards the west. The crystal, re- sembling in that also a magnetic needle, showed strong polarity ; the same end being always directed to the north. I think this may be a polarity of the opto-magneiic power. Between the poles of the strong electro-magnet, the permanent polarity disappeared as long as the magnetism was excited." Mr. Alger, in communicating to the American Association these discoveries of Pliicker, made some remarks concerning cyanite, which may perhaps render the subject a little clearer. He said, referring to the effect observed, " This is, of course, founded on the recently discovered magnetic property of aluminum, but in the highly oxidized state in which this metal exists in cyanite, it would hardly seem pos- sible that the direction which the crystal assumes should be due to its metallic base ; nor can we suppose the presence of iron in sufficient quantity to cause it ; yet we must place confidence in so high an authority. Pliicker finds, also, that there is some connection between the direction that cyanite assumes and its cleavage planes." The subject deserves further investigation, and Mr. Alger recommended American mineralogists to examine other aluminous minerals of the same class with respect to their magnetism. 132 ANNUAL OF SCIENTIFIC DISCOVERY. ON THE CRYSTALLINE POLARITY OF BISMUTH. WE find in the Philosophical Transactions for 1849, Part L, a long paper by Prof. Faraday, "On the Crystalline Polarity of Bismuth and other Bodies, and on its Relation to the Magnetic Form of Force." The author states, that in preparing cylinders of bismuth, by casting them in glass tubes, he had often been embarrassed by the anomalous magnetic results which they gave, and that, after a. close investigation, he has referred the effects to the crystalline condition of the bismuth. If bismuth be crystallized in the ordinary way, and then a crystal, or a group of symmetric crystals, be selected and suspended in the mag- netic field between horizontal poles, it immediately either points in a given direction, or vibrates about a given position, as a small mag- netic needle would do ; and if disturbed from this position, it returns to it. On re-suspending the crystal, so that the horizontal line, which is transverse to the magnetic axis, shall become the vertical line, the crystal then points with its maximum degree of force. If it be again suspended so that the line parallel to the magnetic axis be rendered vertical, the crystal loses all directive force. This line of direction, therefore, which tends to place itself parallel to the magnetic axis, the author calls the magnecrystallic axis of the crystal. It is perpendic- ular or nearly so, to the brightest and most perfect of the four cleav- age planes of the crystal. Whether this magnecrystallic axis is parallel or transverse to the magnetic axis, the bismuth is in both cases repelled from a single or the stronger pole ; its diamagnetic relations being in no way affected. If the crystal be broken up, or if it be fused and solidified, and the metal be then subjected to the action of the magnet, the diamagnetic phenomena remain, but the magne- crystallic results disappear, because of the confused and opposing crystalline condition of the various parts. If an ingot of bismuth be broken up, and fragmentary plates selected which are crystallized uniformly throughout, these also point; the magnecrystallic axis be- ing, as before, perpendicular to the chief plane of cleavage, and the external form, in this respect, of no consequence. The position of the crystal in the magnetic field is affected by the approximation of extra magnets or of soft iron ; but the author believes this to result, not from any attractive or repulsive force exerted on the bismuth, but only from the disturbance of the lines of force, or re- sultants of magnetic action, by which they acquire, as it were, new directions ; and as the law of action which he gives is, that the line or axis of magnecrystallic force tends to place itself parallel, or as a tangent, to the magnetic curve, or line of magnetic force, passing through, the place where the crystal is situated, so the crystal changes its position with any change of direction in these lines. Crystals of antimony, arsenic, native crystals of iridium and osmium, and crystallized titanium and "tellurium, gave similar results, but in different degrees. Crystals of zinc, copper, tin, lead, gold, &c., gave no signs of being magnecrystallic. Crystals of sulphate of iron are very strongly affected by the magnet according to this new condition, and the magnecrystallic axis is perpendicular to two of the planes of NATURAL PHILOSOPHY. 133 the rhomboidal prism, so that, when a long crystal is used, it will not, as a mass, point between the poles, but across the line joining them. On the other hand, sulphate of nickel has its magnecrystallic axis parallel, or nearly so, to the length of the ordinary prism. Diamond, rock-salt, fluor-spar, boracite, red oxide of copper, oxide of tin, cin- nabar, galena, and many other bodies, presented no evidence of the magnecrystallic condition. Having thus stated the effects produced, Dr. F. enters upon the consideration of the nature of the magnecrystallic force. He found that bismuth has the same amount of repulsion when presenting its magnecrystallic axis parallel or transverse to the lines of magnetic force acting on it, and he was led by an ingenious series of experi- ments to conclude that it is neither attraction nor repulsion which determines the final position of a magnecrystallic body. He next considers it as a force dependent upon the crystalline con- dition of the body, and, therefore, associated with the original mo- lecular forces of the matter, and shows experimentally, that, as the magnet can move a crystal, so also the crystal can move a magnet ; and, also, that heat takes away this power just before the crystal fuses, and that cooling restores it in its original direction. Coming next to the question, whether the effects are due to a force altogether inherent in the crystal, or whether they are not partly induced by the magnetic or electric forces, he concludes that the force manifested in the magnetic field, which appears by external actions, and causes the motion of the mass, is almost entirely induced, in a manner subject, indeed, to the crystalline force and additive to it, but at the same time exalting the force and the effects to a degree which they could not have approached without the induction. To this part of the force he applies the word magneto-crystallic, in contradistinction from the word magnecrystallic, which is used to express the condition, quality, or power which belongs essentially to the crystal. The author then con- tinues his investigations, and concludes with some appropriate remarks on the progress recently made in the knowledge of magnetism, its powers and effects. MAGNETIC ACTION ON RAILWAYS. IT is well known that an opinion has prevailed among scientific men for a few years, that railway axles, after having been used for some time, become crystallized by galvanic action, and are then very easy of fracture. The subject was brought before the late meeting of the British Association by Mr. Greener, who, without questioning the fact, stated that the axles were affected with electricity generated by the bearings and the journal while in rapid motion. He said, that by subjecting inferior iron to currents of electricity, it was soon changed into a crystalline state, and lost its tenacity. Mr. Stephenson said, that it was dangerous to assume facts and rea- soning from the assumptions of Mr. Greener. With respect to the in- fluence of vibration on the structure of iron, he considered that there was good room to doubt that the bearing force or pressure upon metals caused crystallization. It was by no means proved that railway axles 12 134 ANNUAL OF SCIENTIFIC DISCOVERY. Were subject to the passage of currents of electricity, and therefore granting the assumption that the passage of the electric current changed the character of the iron there was a link wanting in the chain of reasoning, inasmuch as it was not proved that axles were subject to this electrical influence. Moreover, he was inclined to doubt whether, if a piece of iron was at first perfectly fibrous, vibra- tion would ever change the structure of the metal. The beams of Cornish engines, for example, were subject to vast pressure ; they never become crystallized: the connecting-rod of a locomotive was subject to great vibration, strain, and pressure, vibrating eight times a second when the velocity is forty miles an hour ; he had watched the wear of a rod for three years, and no change was perceptible in the structure of the iron. SELF-REGISTERING MAGNETIC NEEDLE. ONE source of error has constantly attended magnetic observations in the most perfectly constructed observatories. The approach even of the observer has been sufficient to produce a disturbance in the magnetic needles or bars. This error, however, no longer exists. Each magnetic bar is made to carry a little mirror, which reflects the light of a lamp upon a piece of photographic paper kept constantly moving behind an opaque plate having but one small vertical opening. On this, for every minute of the twenty-four hours, each vibration of the needle is faithfully recorded. The chemical radiations of an Argand lamp supply the observer's place ; and at the same time, as it records every change in the phenomenon of terrestrial magnetism, it is made to mark the most delicate alternations in atmospheric pressure, and to note every increase or diminution of temperature. At Greenwich, the magnets, the barometers, and the thermometers are all registered by the chemical power of light ; and M. Faye and Gonjon, at Paris, knowing the error of the human eye in observations on a bright object, have substituted the Daguerreotype plate for the purpose of ascertaining the actual diameter of the sun, and they pro- pose to the principal observatories of Europe to determine by a similar method the absolute time. Electricity now determines the longitude, and marks the transit of a star, and the sun's, rays perform equally im- portant offices to aid the natural philosopher in his delicate research for the truths which are as yet obscure. London Aihen&um, March. MAGNETIZED BRASS. REV. MR. RANKIN stated at the last meeting of the British Asso- ciation, that he had found the northern half of a brazen meridian of a celestial globe to be so strongly magnetic as to deflect a small needle placed near it so much as eight points from its true direction, while the southern part of it seemed to be wholly free from magnetism. London Athen&um. NATURAL PHILOSOPHY. 135 OX THE DIURNAL VARIATIONS IN THE DECLINATION OF THE MAGNETIC NEEDLE, ETC. i PROFESSOR W. A. NORTON, of Delaware College, has communi- cated to Sillimari's Journal a long and interesting article upon this subject, which is at present exciting much discussion. He says: " In a former memoir I gave an exposition of a new theory of Terres- trial Magnetism, of which the following are the fundamental princi- ples. 1. Every particle of matter at the earth's surface, and to a cer- tain extent below the surface, is the centre of a magnetic force exerted tangentially to the circumference of every vertical circle that may be conceived to be traced around it. 2. The direction of this force is different, according as it solicits the north or south end of the needle ; and it is always such, that to the north of the acting particle the ten- dency is to urge the north end of the needle downward and the south end upward, and to the south of the same particle it is the opposite. 3. The intensity of the magnetic force of a particle of the earth, at a given distance, .is approximately proportional to its temperature, or amount of sensible heat; and at increasing distances diminishes ac- cording to some unknown law. From these principles I deduced three simple formulas ; one, for the horizontal component of the directive force of the needle, or the horizontal magnetic intensity of the place ; a second, for the vertical intensity ; and a third, making known the declination. These formula? were afterwards tested by numerous comparisons with the results of observations made in every variety of locality in the northern hemisphere of the earth. The agreement was found to be very close, the differences amounting only to a few hun- dredths for the horizontal and vertical forces, and less than 2 40', and in most cases less than 1, for the declination. The positions of the magnetic poles, the pole of maximum intensity, and the magnetic equator, were also theoretically deduced, and shown to correspond very closely with their observed positions. " In view of the whole discussion, the following great truths were supposed to have been established. 1. All the magnetic elements of any place on the earth may be deducted from the thermal elements of the same ; and all the great features of the distribution of the earth's magnetism may be theoretically derived from certain prominent fea- tures in the distribution of its heat. 2. Of the magnetic elements, the horizontal intensity is nearly proportional to the mean temperature, as measured by a Fahrenheit thermometer: the vertical intensity is nearly proportional to the difference between the mean temperatures at two points situated at equal distances north and south of the place, in a direction perpendicular to the isogeothermal line (that is, a line con- ceived to be traced through all points at which the mean temperature of the matter of the earth near its surface is the same as at the station of the needle); and in general the direction of the needle is nearly at right angles to the isogeothermal line. 3. As a consequence, the laws of the terrestrial distribution of the physical principles of mag- netism and of heat mu.st be the same, or nearly the same ; and these principles themselves must be physically connected in the most inti- 136 ANNUAL OF SCIENTIFIC DISCOVERY. mate manner. 4. The principle of terrestrial magnetism, in so far as the phenomena of the magnetic needle are concerned, must be confined to the earth's surface, or to a comparatively thin stratum of the mass of the earth. 5. The mechanical theory of terrestrial magnetism, which has been under discussion, must be true in all its essential features. 6. We may derive the magnetic elements by very simple formulae from a very small number of magnetic data, determined by observation and the mean annual temperature of the place. "From the theoretical investigation of the normal state of the ter- restrial magnetic elements, I propose now to proceed to the discussion in the light of the same theory of tlieir diurnal variations. This theory furnishes as the following general principles as a basis for this discus- sion. 1. The horizontal magnetic intensity is proportional to its tem- perature. 2. The vertical intensity is proportional to the difference between the temperatures of two places situated at equal distances north and south of the isogeothermal line, in a direction perpendicular to it. 3. The direction of the needle is nearly perpendicular to the isogeothermal line. From these general principles we may draw the general conclusions, that the variations of the horizontal and vertical magnetic intensities must be linked to the variations of the tempera- ture of the station of the needle and of the differences of -temperature of places north and south of this, and that the variations of declina- tion must be connected with the variations in the position of the ideal line passing through all places which have the same actual tempera- ture as the given place ; which line may be called the true isogeother- mal line. If the latter conclusion be true, it may be added, that the variations of declination must also be connected with the variations in the differences of temperature of places situated to the east and west of the station of the needle." Professor Norton then gives a formula for the horizontal intensity of a place, furnished by the above theory, which is equivalent to the statement, that the mean horizontal magnetic force is proportional to the mean temperature. "We have, therefore, to compare the diur- nal variations of the horizontal force with those of the temperature of the place. The theory strictly requires that the comparison should be with the daily variations in the absolute amount of sensible heat near the earth's surface, but from well-known facts it is evident that a rise or fall of surface-temperature will, in general, indicate an in- crease or decrease of the total amount of heat. This suffices for the inquiry which first arises, viz., whether the horizontal force increases and decreases with the total amount of heat." Professor N. then compares some curves arranged so as to show the mean daily varia- tion of the horizontal intensity with that of the temperature for the year 1844. It is found that the horizontal intensity attains its maxi- mum from 3 to 4 P. M., and that " the maximum temperature occurs at the same hour; also that the intensity increases with the tempera- ture in the forenoon after 10 o'clock, and decreases with it in the af- ternoon and evening. The same correspondences are found in other years and quarters of years, with the qualification that the maximum horizontal intensity sometimes occurs an hour or two later than the NATURAL PHILOSOPHY. 137 maximum of temperature. They indicate that the daily variation of temperature is probably one cause of the variation of intensity. We find, further, that the horizontal force increases during the latter half of the night, till 5 or 6 A. M., and then decreases till 10 A. M., where- as the temperature falls steadily till 5 or 6 A. M., and after that be- gins to rise. Thus, in the one case there are two maxima and two minima, and in the other, only one of each. Again, while the tem- perature falls in the afternoon and evening as rapidly as it rises in the forenoon, the horizontal force decreases less rapidly during the former period than it increases during the latter ; and, as intimated, the max- imum of intensity is sometimes an hour or two later than the maximum of temperature." Here are discrepancies between the actual and the theoretical vari- ations of the horizontal force which are to be accounted for. Profes- sor Norton calls them secondary variations, merely to distinguish them, without intending to imply that they are of minor importance. The inevitable inference from these discrepancies is, that if the dai- ly variation of temperature is one cause of the daily variation of the horizontal force, there must also be some other cause at work besides this. It seems probable, for various reasons, that this additional cause is merely some indirect effect of the variation of temperature; the chief reason is, that the time of the secondary maximum of in- tensity moves backwards and forwards with the time of sunrise. Professor Norton then examines the subject with great minuteness by means of tables and facts ; he takes up the arguments for and against various causes, examines into the laws of the radiation of heat, and finally says, " In view of all that has now been stated, it may be confidently affirmed, that if the cause of the two anomalous facts con- nected with the nocturnal loss of temperature be any meteorological phenomenon, it must be the deposition of vapor from the atmosphere in other forms than that of rain, and chiefly, therefore, in the form of dew. Either this must be the actual cause, or it must consist in the laws of the earth's cooling at night, irrespective of all atmospheric influences." A little further on he states his conclusion in somewhat different words. " I conclude that the cause of the nocturnal varia- tions of the horizontal force must either consist in variations in the amount of vapor deposited from the atmosphere, or be in some way connected with the upward flow of heat below the earth's surface." The author then takes up this latter alternative of the upward flow of heat, and concludes that it "fails entirely to explain the unequal losses of temperature at night in different seasons of the year." Having come to this conclusion, that the secondary variations can be accounted for by nothing else than by the variation in the amount of dew deposited in different seasons, and in different hours of the night, and the consequent variation in the quantity of heat given out in the condensation of vapor into dew, he makes a minute examination into the quantity of dew that falls, and says, " I conclude, therefore, that the heat evolved from the dew, or condensed vapor, that falls at night, is nearly if not quite sufficient to reduce the theoretical decrease of temperature due to radiation down to the amount which actually ob- 12* 138 ANNUAL OF SCIENTIFIC DISCOVERY. tains; and that the variations in the quantity of dew that falls at night, from one season to another, are attended with sufficient varia- tions in the amount of heat imparted to the earth, to effect the changes observed in the nocturnal decrease of temperature during the year. I consider that in the average of months the amount of dew deposited from hour to hour during any one night, and from night to night, must increase steadily from sunset to sunrise, and from summer to winter. It follows from these conclusions that the probable cause of the secon- dary variations of the horizontal force is to be found in the varying quantities of dew deposited from one hour to another, and from one season to another." After some further remarks, Professor Norton shows that the actual effects of dew will, in particular cases, account for the variations observed between his theory and the results as at first found, or in other words, it will account for the discrepancies be- fore referred to. He next comes to the diurnal variations of the vertical mngnetic in- tensity. The general theory is that the vertical intensity is proportion- al to the difference of temperature of two places situated at equal dis- tances to the north and south of the station of the needle, and on a line perpendicular to the isogeothermal line. He finds that the actual state of things agrees at least approximately with his theory. There is, how- ever, a slight discrepancy here also, for we find that the variations in the vertical intensity are generally less for the first and last than for the other two quarters of the year, while there is not an equal propor- tionate difference in the variations of temperature. This discrepancy is probably owing to this, that instead of taking the difference between the temperatures at the earth's surface, we should take the difference between the average temperatures of the stratum just below the sur- face, which is subject to a daily variation of temperature. This must be settled, however, by further investigation. The last subject treated of is the diurnal variations of the declina- tion. In this particular the general theory is, that the needle is near- ly perpendicular to the isogeothermal line, that is, that the mean position of the needles is at right angles to the ideal line passing through those places which have the same mean annual temperature. This, Professor Norton considers to be also rendered probable by vari- ous facts which he states. He has some very correct remarks to the effect, that no theory should be rejected because, while it seems to ac- cord with facts in all its important points, there are some minor discre- pancies. ON THE DIRECT PRODUCTION OF HEAT BY MAGNETISM. AT the meeting of the Royal So iety of London, on the 24th of May, W. R. Grove, Esq., read an interesting paper " On the Direct Production of Heat by Magnetism." The author recites the experi- ments of Marrian, Beatson, Wertheim, and De la Rive, on the phe- nomenon which was discovered some years ago, that soft iron, when magnetized, emits a sound or musical note. He also mentions an experiment of his own where a tube was filled with the liquid in NATURAL PHILOSOPHY. 139 \vhich magnetic oxide had been prepared, and surrounded by a coil ; this exhibited to the spectator looking through it, an increase of the transmitted light when the coil was electrized. All these experi- ments, he considers, go to prove that, whenever magnetization takes place, a change is produced in the molecular condition of the sub- stances magnetized ; and it occurred to him that, if this be the case, by a species of molecular friction heat might be produced. In proving the correctness of these conjectures, many difficulties presented them- selves, the principal of which was, that with electro-magnets, the heat produced by the electrized coil surrounding them might be ex- pected to mask any heat developed by the magnetism. This interfer- ence he eliminated by surrounding the poles of an electro-magnet with cisterns of water," and by this means, and by covering the keeper with flannel and other expedients, he was enabled to produce, in a cylindrical cast-iron keeper, when rapidly magnetized and demagnet- ized, a rise of temperature several degrees beyond that which obtain- ed in the electro-magnet, and which therefore could not have been due to the radiation of "heat from it. By filling the cisterns with water colder than the electro-magnet, the latter could be cooled, while the keeper was being heated by magnetization. Subsequently, distinct thermic effects were detected in a bar of soft iron, placed opposite to a rotating permanent steel magnet. To separate the effects of magneto- electrical currents, the author then made experiments with non-mag- netic metals and with silico-borate of lead, substituted for the iron keepers, but no thermic effects were developed. He then tried the magnetic metals, nickel and cobalt, and obtained thermic effects with both, in proportion to their magnetical intensity. The author then concludes by saying that he considers that these experiments prove that, whenever a bar of iron or other magnetic metal is magnetized, its temperature is raised. Mechanic's Journal. ON THE POLARIZATION OF HEAT. THE polarization of heat, first announced by Berard, has been established by various experiments by Forbes and Melloni. Provost- aye and Desains have lately announced to the Academy of Sciences, at Paris, new investigations, showing, 1st. That heat, traversing Iceland spar, is divided into two pencils, completely polarized in the plane of the principal section or a perpendicular plane. 2d. That the law ascertained by Malus, according to which the intensity of a ray- completely polarized is divided between the ordinary and extraordi- nary images to which it gives origin in traversing the spar, is appli- cable to heat as well as light. 3d. That the variations of intensity which polarized heat experiences in its reflection from glass at differ- ent incidences, are exactly represented by FresnePs formulas deter- mined for light, only allowing that the solar heat traversing the prism has a little different index/ 1.5. 4th. That there is a most perfect correspondence between the phenomena presented in the reflection from polished metals of polarized heat and polarized light. 140 ANNUAL OF SCIENTIFIC DISCOVERY. THE PHENOMENA OF THE DAGUERREOTTPE PROCESS. M. CLATJDET has communicated to the British Association a paper " On Researches on the Theory of the principal Phenomena of Photog- raphy in the Daguerreotype Process." Light produces two differ- ent effects on the Daguerreotype plate, capable of giving an image. By one, the surface is decomposed, and the silver is precipitated as a white powder; this action is very slow. By the other, the parts affected by light receive an affinity for the mercurial vapor, and this metal is deposited in white crystals. This action, which is the cause of the Daguerreotype image, is 3,000 times more rapid than the for- mer. The two cannot proceed from the same cause. The first is a chemical decomposition of the surface, while the second is a new prop- erty imparted to the surface to attract the vapor of mercury, which is given by some rays and withdrawn by others, the most refrangible rays being the ones which produce the affinity for mercury. M. Claudet has so improved his photographometer that he can compose upon the same plate a series of intensities in a geometrical progres- sion, varying from 1 to 512, or by employing two plates at the same moment," from 1 to 8,192. He is also enabled to study the modifica- tions produced on various intensities of effect by the radiation of half the light, through various colored glasses. M. Ciaudet has ascertained one remarkable and inexplicable fact, that the two foci for the same distance of an object sometimes coincide and sometimes vary very far from one another ; and the difference varies according to some un- known properties of the lenses, so that while the foci correspond in some lenses, they may be separated in others. London Athenccum, Sept. COLORED PHOTOGRAPHS. THE Comptes Rendus, of the 12th February, contains the report of M. Biot and others, on the process discovered by M. Becquerel, of making photographic copies of colored objects with distinct impres- sions of the colors on the body so copied. The prospect, however remote at present, of being able to copy Nature in all the truth of color, gives great interest to every experiment which leads to an advance in this particular. The main features of the new process are the following. The ordinary silver plate, well polished, is con- nected with the positive pole of a battery of two series, and then plunged into a large vessel containing diluted hydrochloric acid. In the same fluid is placed a third plate of platina, which communicates with the negative of the battery. This plate is brought very rapidly a short distance from and parallel to the other. Under these condi- tions, the plate assumes successively the colors of thin films; at first a gray, then a yellow and violet tint, which passes soon to a blue and to a green, and becomes afterwards rose-colored, then violet, and at last blue. The operation must be stopped as soon as a lilac tint ap- pears, and the plate withdrawn rapidly from the bath, washed with distilled water, and being placed in an inclined position, dried over a NATURAL PHILOSOPHY. 141 spirit-lamp. The plates thus prepared may be preserved in the dark for a long 1 time. In diffused light, the surface of chloride of silver, thus prepared, becomes gray ; but if \ve project a very pure and con- centrated prismatic spectrum, it recehes, at different rates, impressions from all the visible luminous rays in their respective colors, at the same time that very decided colors are produced by the non-luminous rays below the red and beyond the uolet. By warming the prepared plate some curious changes are produced ; and if warmed on a stove to about 212 Fahrenheit, M. Becquerel states that the most perfect condition for imprinting the spectral colors is brought about. The time which the plate should be exposed to the solar spectrum varies with its intensity ; when very concentrated, in a few minutes a fine- ly colored impression is obtained. These photographic images may be preserved for a considerable time in the dark-; but as yet no means have been discovered by which they can be rendered permanent against the continued action of light. Admiring the zeal with which M. Becquerel has pursued his re- searches on this curious subject, we must not forget that Sir John Herschel has also succeeded in obtaining a colored impression of the spectrum, on paper prepared with vegetable juice ] and that Mr. R. Hunt got a similar result with fluoride of silver. We may, therefore, reasonably hope that eventually the pencil of the sunbeam will add the charm of color to the chemical pictures it produces. London Athenccum. LUNAR DAGUERREOTYPES. THE existence of actinism, or the chemical principle of light, in the rays reflected from the moon's surface, has heretofore been a question of considerable doubt and uncertainty. At a meeting of the British Association, at Cork, some years since, Dr. Robinson stated, " that he had been led by the success of Professor Rondoni of Rome, in procuring Daguerreotype images of various fixed stars and nebulas by means of light transmitted from these objects, to endeavour to procure a Daguerreotype impression of the moon's surface. A portion of the disk of the moon was brought within the range of a powerful reflect- ing telescope, and the brilliant image formed thrown upon a Daguerre- otype plate placed in the focus of the reflector. The plate was left exposed in this situation for twenty minutes. Although a good im- pre^sion of a building could be procured upon plates similarly pre- pared, in a minute, yet this prolonged exposure to the light of the moon produced no impression." Dr. Robinson considered the ex- periment as conclusive in establishing the fact, that the chemically active principle known as actinism did not exist in lunar light. Re- sults similar to those of Dr. Robinson, have been also arrived at by various philosophers in Europe and America. Dr. Draper, of New V''.rk, however, has stated that he has been able to detect the ac- tinic element both in moonlight and artificial light. At a meeting of the Cainbridi. 1 ' 1 Scientific Association, December, 1849, five Daguerreotype pictures of the moon's surface were exhibited to the Society by Mr. Wells. These pictures were taken by Mr. 142 ANNUAL OF SCIENTIFIC DISCOVERY. S. D. Humphrey, of Canandaigua, N. Y., with a half-size American camera, on a medium plate. The first picture was obtained by an ex- posure of two minutes, the camera remaining permanent. During- this short interval, the earth had moved forward so rapidly, that the figure of the satellite was elongated to form an oval, or egg-shape picture. The same peculiarity was also noticed in the pictures obtained by an exposure for one minute, and also for thirty seconds, though in a less degree. In these pictures, the configurations upon the moon's surface were not delineated, but in the fourth picture, obtained by an exposure of three seconds, the representation was strikingly clear and distinct. The figure was round, and the representation of the surface so perfect, that its appearance, when examined under the microscope, somewhat resembled the full moon seen through a telescope. The fifth picture was obtained by an exposure of only half a second, and was little more than a shadow. The powerful agency and presence of the chemical principle was sufficiently indicated by it. These sev- eral pictures were all taken upon one occasion, on the night of the 1st of September, a few hours before full moon. They conclusively show that lunar light possesses the chemical principle or force, in a high degree, and it is to this source that we may reasonably attribute its supposed action in producing phosphorescence and other changes ia animal or vegetable substances. Editors. PICTURES ON GLASS. AT a late meeting of the French Academy M. Evrard communi- cated the details of a process he has discovered, by which pictures can be taken upon glass. The principle of the discovery is a matrix of albumen, rendered sensitive to the action of light by aceto-nitrate of silver, and spread in a thin layer upon a plate of glass. The pro- cess is to take a certain number of the whites of eggs, and remove all the non-transparent part, and then add a few drop.s of a saturated so- lution of iodate of potassium, then beat the eggs into a froth, and allow the whole to settle. The plate of glass must be well cleaned with alcohol, and the albumen is then spread over it, in a thin layer, with another piece of glass. It is important that the glass should have a perfect, thin coat adhering to it, and to obtain this it must next be hung up by one of the corners, so that the excess may drain off, after which it should be placed to dry upon a level board, and screened from the dust. Then the glass is dipped into a solution of aceto- nitrate of silver, face downwards, after which it is stirred about in a basin of clean water for a few seconds, and is then completely sensi- tive to receive photographic impressions, either when it is moist or dry. It is then placed ia the camera-obscura, after which it is dipped for a short time into a bath of gallic acid, in which there is a little of the nitrate of silver. Finally, it is washed in water, and having been immersed in a solution of bromide of potassium, it is again washed, and left to dry in a horizontal position in a dark room. NATURAL PHILOSOPHY. 143 THE PHOTO GRAPHOMETER. AT a late meeting of the Paris Academy of Sciences, M. Clandet communicated a. description of his newly invented instrument, for in- dicating to the 'photographer the intensity of the chemical rays, and at the same time the sensitiveness of his preparation. The apparatus is very simple, and serves equally for processes on paper and on metallic plates. It indicates the intensity of the chemical rays at all times of the day during atmospheric variations, and at the instant we may wish to operate. It serves also to compare the degree of sensitiveness of the different photographic preparations. It is necessary that an in- strument of this kind should have a uniform motion without intricate machinery, and this is obtained by a means founded upon the princi- ple of bodies sliding down an inclined plane. The sensitive surface is exposed to the light by the rapid and uniform passage of a metal plate, having openings of different lengths which follow a geometric progression. It is evident that the exposure to the light will be the same for each experiment, because the plate falls always with the same rapidity, the height of the fall being constant, and the angle of the plane always the same. The photogenic surface, whether it be the Daguerreotype plate, the Talbotype paper, or any other sensi- tive preparation, is placed near the bottom of the inclined plane, and is covered with a thin plate of metal pierced with circular holes, which correspond to the openings of the moveable plate. By placing beneath each series of holes a different sensitive surface, each of these will receive the same proportion of the same light, and thus the dif- ferent degrees of sensitiveness may be compared. It is indispensable, in making an exact comparison, to operate with the same light and during the same space of time, as it is known that the light varies from one minute to another ; this is accomplished by the photograph- ometer. M. Claudet announces that this apparatus has furnished him with a very extraordinary fact, which, however, he does not give as precisely correct ; but he thinks that he cannot be far from the truth in stating, that the pure light of the sun modifies the bromo-iodized sil- ver plate, communicating to it an affinity for mercurial vapor, which produces the white image in the Daguerreotype, in about the thou- sandth part of a second. He made the experiment by admitting the light of the sun through an opening of a French millimetre in size, and this opening passed over a space of 350 millimetres in a quarter of a second, so that the light could not have acted on the plate more than the thousandth part of a second. It is suggested that this in- strument may be used to ascertain the effect of the compound light, and that of the different separated rays of the solar spectrum ; how much photogenic light is lost by reflection from parallel mirrors, prisms, and other substances, and by refraction through lenses ; the propor- tion of photogenic rays in the light obtained from various sources, in- cluding that produced by electricity ; if the photogenic light varies with the height of the atmosphere and with the changes of tempera- ture, and if it is affected by the electrical state of the atmosphere ; and, lastly, what is the proportion of the photogenic rays at each hour of the day, and at different points in space at a given moment 144 ANNUAL OF SCIENTIFIC DISCOVERY. ON SOME NEW PHENOMENA OF LIGHT AND ACTINISM. THE following is an abstract of a paper recently presented to the Royal Society by Robert Hunt, Esq. The chemical change pro- duced in chloride of silver when exposed to the action of the sun's rays, by which powerful chemical affinity is broken up, chlorine lib- erated, and silver in a state of fine division left, was selected as an ex- emplification of the actinic force, which was the subject of considera- tion. This chemical change takes place in white light, and hence all those photographic phenomena which have created so much interest have been referred to luminous power. If, however, we examine the conditions of light as analyzed by the prism, presenting, not seven colored bands, as stated by Sir Isaac Newton, but nine as proved by recent experiments, it is found that these colored bands possess op- posite properties. For instance, the chloride of silver will not darken in the mean luminous ray of the spectrum, nor will it darken either at the end which gives the greatest calorific effect, or at the end which is embraced by the lavender ray, usually regarded as representing the most chemically active part ; consequently we find three points in the spectrum which will not produce any change in chloride of silver. Where we have the most light, and at two extremities where the light ceases to affect the human eye, and also laterally, bands are ex- hibited which show the same physical conditions, and thus it would appear that the circle of light is not the agent producing this peculiar alteration. Regarding, as appears natural, the ordinary prismatic spectrum as the representation actually of two spectra consisting of but three colors, red, blue, and yellow, which is shown by the re- appearance of red light in the blue and of yellow light in the lavender ray, which blue light appears again at the least refrangible end in the extreme red or crimson ray, we have an explanation of the result above mentioned, and the want of chemical action is shown to arise from the operation, indeed, of the most luminous bands. By absorbent media, as colored glasses and fluids, these results were more fully ex- plained. The most remarkable results have, however, been lately ob- tained by the use of colored media ; and it has .been shown that every luminous ray, independent of color, may be made to protect chloride of silver from that chemical change which is induced by the direct ac- tion of diffused daylight, the portion upon which those rays foil be- ing actually preserved as a white space, every other part .being black- ened. It was contended that no hypothesis of interference would explain this result, which more decidedly proved than had hitherto been done, the wide difference between the phenomena of light and actinism. The fact that luminous effect phosphorescence was produced by the blue rays of the spectrum, appears to oppose this view ; but when we find that, in like manner, electricity was interrupt- ed, it appears more rational to refer phosphorescent phenomena to some peculiar electric excitation. The action of the solar rays on the developement of vegetable life was then explained, and the following conclusions suggested as the explanation of experimental results fre- quently repeated; 1. Germination, which will take place in the NATURAL PHILOSOPHY. 145 dark, is quickened by the actinic force, and retarded and often stopped by the luminous power. 2. Lignijlcation. The decomposition of carbonic acid by the plant is due to some excitement of luminous power, and is slopped by the actinic force. 3. Formation of Chloro- phyll. Due entirely to the luminous rays. 4. Flowering and Fruit- ing. Dependent upon the action of the thermic or parathermic rays of the spectrum, as distinguished from both the luminous and actinic forces. 5. Motion of Plants. Bending to the blue light, and reced- ing from the red, proving the excitement of actinic force. London Athenaum, April. THE VELOCITY OF LIGHT PROVED BY ACTUAL EXPERIMENT. IT is well known that the proof of the enormous velocity of light, amounting to 192,000 miles per second, has hitherto been derived only from the observations and calculations of astronomers and geometri- cians, and that this velocity has never been demonstrated by any ex- periment. In 1675 Roemer first announced the extraordinary velocity of light, which he had derived from observations on the satellites of Jupiter, and in 1728 Bradley was led to the same result by studying the phenomena known as " the aberration of light." Since the same result was thus arrived at in two totally different ways, there could be no doubt of the fact ; but still scientific men have long desired to ren- der it more evident by actual experiment. This has at last been ac- complished T>y a French savcm, M. Hippolyte Fizeau, from whose communication to the French Academy, on July 23d, we make the fol- lowing extracts. "I have succeeded in demonstrating the velocity of light by a method which seems to me to furnish a new means of study- ing with precision this important phenomenon ; this method is founded on these principles. When a disk turns in its plane with great rapidity around its centre of figure, it is possible to estimate the time occupied by a point in the circumference in describing a very small angu- lar space, a thousandth of the circumference for example. If the rapidity of rotation is great enough, this time is very short, being for ten or a hundred revolutions per second only one ten-thousandth or one hundred-thousandth of a second. If the circumference of the disk is divided, like a toothed wheel, into equal intervals, alter- nately open and closed, the time occupied by the passage of each of these intervals through the same point of space will be the same small fractions. During so short periods the light passes over quite limited spaces, being 31 kilometres (19.5 miles) for the first fraction, and 3 kilometres (2 miles) for the second. If a ray of light which has passed through one of the divisions of the wheel is reflected from a mirror placed at a certain distance, and returns to the same point, the time occupied in the propagation of this ray must necessarily inter- vene, and the ray at its return will pass through an open space in the wheel, or will be stopped by a closed one, according to the rapidity of the motion of the wheel and the distance from which the light is re- flected. * A system of two telescopes directed towards each other, so that the 13 146 ANNUAL OF SCIENTIFIC DISCOVERY. image of the object-glass of each is formed in the focus of the other, furnishes us, in a very simple manner, with the essential condition of a ray of light, which, starting from a point, is reflected at a certain dis- tance so as to return to its starting-point. For this all that is necessary is to place in the first telescope, between the focus and the eye-glass, a transparent glass at an angle of 45 degrees, which sends towards the object-glass the light received obliquely from a lamp or from the sun; and also to place a mirror in the focus of the object-glass of the sec- ond telescope. This arrangement answers perfectly, even when the telescopes are separated to a considerable distance. With telescopes of an aperture of 6 centimetres (2.5 inches) the distance may be 8 kilometres (5 miles) without weakening the light too much. We then see a luminous point like a star, formed by the ray of light, which, starting from the focus of the first telescope, and being reflect- ed by the inclined glass through a space of 16 kilometres (10 miles), returns exactly to the same point of departure, traverses the same plate of glass, and finally enters the eye. " It is through the point of departure that the teeth of the revolving disk must be passed to produce the effects indicated. The experi- ment is made without any trouble, and the least practised eye per- ceives immediately that, according to the greater or less rapidity of the motion, the point of light shines brightly or is wholly eclipsed, as it meets an open or closed space. Under the circumstances in which I made the experiment, the first eclipse took place when the disk was revolving at the rate of about twelve revolutions and six tenths per second. With a double rapidity the point again shone out, was eclipsed with a triple rapidity, reappeared with a quadruple one, and so on. The first telescope was placed in the cupola of a house sit- uated at Suresnes, and the second one upon the heights of Mont- martre at the approximate distance of 8,633 metres. The disk, having on it 720 teeth, was mounted on wheel-work moved by weights ; a scale furnished the means of measuring the rapidity of the rotation. The light came from a lamp so arranged as to furnish a very brilliant light." If we correctly understand the meaning of M. Fizeau, it is evident, in the first place, that the distance of the telescopes, the rapidity of the rotation, and the interval of time which separates the passage of an open from that of a closed space, are known ; secondly, that the meeting of a ray of light with an open or closed space, and conse- quently its reappearance or its eclipse when it has been reflected back after having passed over the double space of 8,633 metres, de- pends solely upon this distance and upon the velocity with which it has been transmitted, and upon the rapidity with which the disk re- volves. Finally, it follows that the only 'unknown quantity in the problem, the velocity of the ray of light, is deduced at once from the two other quantities previously known, namely, the distance passed over and the rapidity of the motion of the disk, joined to the easy ob- servation of the reappearance or the eclipse. The repeated experiments made in this manner by M. Fizeau give him for the velocity of light a value differing very little from that as- NATURAL PHILOSOPHY. 147 signed by astronomers. The extraordinary agreement of the results obtained in the three ways, from observation on the eclipses of the satellites of Jupiter, from the phenomena of aberration, and from ac- tual experiment, leaves no doubt that light does really travel with the enormous velocity of about 192,000 miles per second. Soon after the above announcement was made by M. Fizeau, he received the cross of the Legion of Honor, as a reward for Ms inge- nuity. NEW OPTICAL INSTRUMENT. PROFESSOR JOHN LOCKE has invented a curious instrument, named by him Phantascope, which will illustrate, in a manner never before accomplished, " single vision by each eye." It is very simple, and has neither lenses, prisms, nor reflectors. It consists of a flat board base, about nine by eleven inches, with two upright rods, one at each end, a horizontal strip connecting the upper ends of the uprights, and a screen or diaphragm, nearly as large as the base, interposed between the top strip and "the tabular base, this screen being adjustable to any intermediate height. The top strip has a slit one fourth of an inch wide and about three inches long from left to right. The observer places his eyes over this slit, looking downward. The movable screen has also a slit of the same length, but about an inch wide. There are two identical pictures of a flower, about one inch in diam- eter, placed the one to the left and the other to the right of the centre of the tabular base, or board forming the support, and about two and a half or three inches apart from centre to centre. A flower-pot or vase is painted on the upper screen, at the centre of it as regards right and left, and with its top even with the lower edge of the open slit. By looking downward through the upper slit, and directing both eyes steadily to a mark, a quasi stem, in the flower-pot or vase, in- stantly a flower similar to one of those on the lower screen, but of half the size, will appear growing out of the vase, and in the open slit of the movable screen. On directing the attention through the upper screen to the base, this phantom flower disappears, and only the two pictures on each side of the place of the phantom remain. The phan- tom itself consists of the two images painted on the base, optically superimposed on each other. If one of these images be red and the other blue, the phantom will be purple. If two identical figures of persons be placed at the proper positions on the lower screen, and the upper screen be gradually slid up from its lowest point, the eye being directed to the index, each image will at first be doubled, and will gradually recede, there being of course four in view until the two con- tiguous coincide, when three only are seen. This is the proper point where the middle or double image is the phantom seen in the air. If the screen be raised higher, then the middle images pass by each oth- er, and again four are seen, receding more and more as the screen is raised. As all this is the effect of crossing the axes of the eyes, it follows that a person with only one perfect eye cannot make the ex- periments. They depend on binocular vision. 148 ANNUAL OF SCIENTIFIC DISCOVERY. All these effects depend on the principle, that one of the two prim- itive pictures is seen by one eye, and the other by the other eye, and that the axes are so converged by looking at the index or mark on the upper screen, that those separate images fall on the points in the eye which produce single vision. To a person who has perfect volun- tary control over the axes of his eyes, the upper screen and index are unnecessary. Such an observer can at any time look two contiguous persons into one, or superimpose the image of one upon the image of the other. We find in a letter from Professor Locke one or two additional ex- periments described. He says : " I took the figure or picture of a person about two inches in height, and, having cut its outline from the paper, and cut off the head, I placed the body to the left on the lower screen, and the head to the right on a level with its proper po- sition, and directed my eyes to the index of the movable screen, when the body appeared to move in from the left and the head from the right till they were apparently reunited, and an entire figure pre- sented itself to view. But, from a little unsteadiness of the eye in a forced position, the head had a small motion, sometimes reaching for- ward in the attitude of earnestness, then drawing back with an expres- sion of dignity. I found, too, that my eyes were not always mates. At one time the body, which was seen by the right eye, appeared bright, while the head, seen by the other eye, was dim and confused. After a little these conditions were reversed, and the left eye gave the brighter image. When the images of two colored objects are opti- cally superimposed by the phantascope, say a blue and red wafer, the phantom will sometimes be purple, again it will be red, when, on re- versing it, the blue will predominate ; showing that one eye is more sensitive to colors than the other, and that the double-imaged phantom will appear of that color which falls on the stronger eye. Throwing aside the machinery of the phantascope, F crossed the axes of my eyes, and looked at the window of my room, increasing the convergence un- til the two images of the window lay side by side, the right-hand side of one image lying along the left-hand side of the other. These edges did not appear to be parallel, the lower ends being apart while the upper ends were in apparent contact. From this it appears that the eyes did not rotate in the same horizontal plane. On throwing the head back as far as possible, and making the same convergence of the axes, the perpendicular objects preserved their parallelism, and the two sides of the two images of the window coincided throughout. Whether this is true of the e'yes of all persons is doubtful. These experiments on^ binocular vision are not so amusing as several others in optics, and to some persons the effort to distort the optical axes is painful, like looking at a double impression in printing. The strug- gle between the knowledge of where the primitive picture really is, and the optical impression of the phantom, is sometimes quite painful ; but, as soon as the imagination realizes the place of the phantom, it is contemplated with as much ease as a real object. There is a math- ematical ratio in the several quantities concerned. For example, the distance from the eye to the phantom is to the distance from the NATURAL PHILOSOPHY. 149 phantom to the object, as the distance between the eyes is to the dis- tance between the identical pictures converged together. It follows, that, any three of the quantities being given, the fourth can be calculat- ed either by proportion or by equation. By this means I calculated the diameter of the floor-cloth panels, the result being within one fourth of an inch of the actual measurement. I mention this merely as an illustration of the subject for the base line ; the distance between the eyes is too short for practical use." This instrument shows that we do not see an object in itself, but the mind contemplates an image on the retina, and always associates an object of such a figure, attitude, distance, and color, as will produce that image by rectilinear pencils of light. If this image on the ret- ina can be produced without the object, as in the phantascope, then there is a perfect optical illusion, and an object is seen where it is not Nay, more, the mind does not contemplate a mere luminous image, but that image produces an unknown physiological impression on the brain. It follows, that if the nerves can, by disease or by the force of imagination, take on this action, a palpable impression is made without either object or picture. As this would be most likely to occur when actual objects are excluded, as in the night, we have an explanation of the scenery of dreams, and the occasional " appari- tions" to waking persons. USE OF COLORED GLASSES TO ASSIST THE VIEW IX FOGS. M. Luvrxi, of Turin, in a letter to the editor of Vlnstitvt^ at Paris, makes the following curious observation, which, if confirmed, may prove to be of great importance : " When there is a fog be- tween two corresponding stations, so that the one station can with difficulty be seen from the other, if the observer passes a colored glass between his eye and the eye-piece of his telescope, the effect of the fog is very sensibly diminished, so that frequently the signals from the other station can be very plainly perceived, when without the colored glass even the station itself is invisible. The different colors do not all produce this effect in the same degree, the red seeming to be the best. Those who have good sight prefer the dark red, while those who are short-sighted like the light red better. The explana- tion of this effect seems to depend upon the fact, that the white color of the fog strikes too powerfully upon the organ of sight, especially if the glass have a somewhat large field. But by the insertion of the colored glass, the intensity of the light is much diminished by the interception of a part of the rays, and the observer's eye is less wea- ried, and consequently distinguishes better the outlines of the object observed." OX AX UXNOTICED KIND OF ABNORMAL VISION. PROFESSOR C. DEWEY communicates to Silliman's Journal, for November, the following notice of a new kind of abnormal vision. There are two well-known kinds of abnormal vision in eyes not dis- 13* 150 ANNUAL OF SCIENTIFIC DISCOVERY. eased, the far-sighted and the near-sighted. The former occurs in good eyes, as persons advance in life, beginning about the age of forty, and is remedied by plane, or, better, by convex spectacles. The latter is found in youth, or young persons, and finds its remedy in con- rave glasses. The far-sighted are unable to see near and small ob- jects, and remove them to an inconvenient distance, while they see remoter objects perfectly well without glasses. The near-sighted are unable to see small objects unless they are brought inconveniently near, and they have no distinct vision of remote objects. There is a kind of abnormal vision, different from either of these, which is not far-sighted nor near-sighted, but in which near small objects, or larger distant objects, are not seen with distinctness. This imperfection oc- , cur.s in children and young persons, and is remedied by convex spec- tacles which are suited to the eyes of persons from sixty-five to sev- enty years of age. The younger eyes require the older glasses, and with advanced years less convex glasses are required. At the age of forty-five or more, this kind of abnormal vision becomes much dimin- ished. As the young use the glasses of the far-sighted, this kind may be called neo-macropia. It is evident that convex glasses produce that change in the rays of light which fits such eyes to see distinctly small and large objects at varying distances. This fact proves that there is no defect in the adjusting power of the eyes. The cause, then, is to be sought in the structure of the eye. As this kind of eyes does not appear to be too much or too little convex, and as the image is not formed soon enough in the eye, or is too far back, either or all of the three following may be the cause: 1st, too little convexiiy of the crystalline lens ; or, 2d, its position too near the retina ; or, 3d, its too little density. The second is the probable cause. Spectacles suf- ficiently convex would bring the rays to a focus, let either or all of the three causes operate, and with the usual adjusting power of the eye give distinct vision for near or remote objects. Though this kind of abnormal vision seems not to have attracted attention, for I have found but one allusion to it in consulting authors on optics, it is relatively common. In New England and New York, more than fifty instances of it have come to my knowledge in the five or six years past. A child of fifteen was able to see distinctly, for the first time, by the use of his grandfather's spectacles. A young man of eighteen required convex glasses of ten-inch focus, while persons of seventy years use those of fourteen to eighteen inch focus. Children often make little progress in study, because they do not see objects distinctly, though the defect is not suspected by them, and is utterly unknown to parents and teachers. The knowledge of this subject will make spectacles a still greater benefit to our race. PHYSIOLOGICAL ACOUSTICS. IN order to ascertain the causes of the same body communicating to our ear different tones at the same time, M. Duhamel has made the following experiment. A caoutchouc thread connected consecutively with different points of an oscillating plate, producing simultaneously NATURAL PHILOSOPHY. 151 two or three notes, was conveyed to one ear, while the other was stopped. He convinced himself that an impression of sound could arrive at the ear in this manner only, and yet all the notes were audi- ble at the same time at all the different points. Hence Duhamel con- cludes, that if the oscillatory motion of one point be decomposed into several others, the ear is affected in the same manner, whether the component movements emanate simultaneously from several neigh- bouring points, or from one point only. Liebig's Annual Report. MIRAGE ON LAKE SUPERIOR. DK. CHARLES T. JACKSON communicated to the American Scien- tific Association, during its session at Cambridge, an interesting paper entitled " Observations on the Mirage seen on Lake Superior in July and August, 1847." Si The phenomena of mirage have at all times excited the wonder and admiration of mankind, and have been fruitful in strange super- stitious legends. Even those most versed in the causes of natural phenomena cannot fail to be strongly impressed with the magnificent phenomena of mirage on the north shore of Lake Superior, and the philosophical mind delights in being able there to observe the causes which produce this marvellous effect. I know not whether the sea- son when I had the opportunity for making my observations was one remarkable for the frequency of mirage, but it is certain that, for many successive days, the phenomena were presenting themselves in rapid succession along the northern coast of Lake Superior, opposite to Isle Royale, and on the coast of the island itself, in the bays which so deeply indent its shoves. At Rock Harbour, on several occasions, I observed the little islands and points on its outskirts most perfectly represented, with inverted pictures of their entire forms hanging over their summits, the images of the spruce and other trees which crown them being seen with beautiful distinctness directly over their terres- trial originals, while the picture of a little skiff was one day seen represented beside the phantom island, the boatman in the sky appear- ing to raw his batteau as unconcernedly as his original on the bosom of the Lake. " On the 27th of July we saw Keweenaw Point in mirage. It is 40 miles distant from this place, and bears E. N. E. from SeoviPs Point on Isle Royale. The most wonderful mirage was observed from the north coast of Isle Royale, while we were coasting along from the eastern to the western end of the island. For several days in succes- sion, we had almost hourly magnificent repetitions of these curious phenomena. Thunder Cape, 15 miles distant to the north, a lofty mural precipice, said to be 1,300 feet high, and rising directly from the lake, presents the form of an irregular truncated pyramid. By the phenomena of mirage it suddenly changes its form into a huge anvil, sending out a long horn to the right, while a dark black mass rises behind it which might be represented as old Vulcan himself. This singular phenomenon attracted much attention, and on observing with care, I found that the horn of the anvil was the image of the 152 ANNUAL OF SCIENTIFIC DISCOVERY. talus of the cliff on the shore, represented in inverted picture. The im- age seen at the summit was probably that of a conical peak in the rear of the cliff, represented inverted over the Cape. Turning away from this phantom for a while, when we looked again the anvil-horn had been removed, and the figure over it was gone ; but it soon reappear- ed as before, and for several days we were gratified \vith a view of these singular and interesting appearances, which seemed like the changes of the magic-lantern. Occasional rumblings of distant thun- der came to us from afar, though no storm visited us. " Not among the least curious and important refractions are those produced on the rays from the celestial bodies. At times the sun yields to the strange refractions, produced by the atmosphere over this great lake, and as he draws near to the horizon expands his broad cheeks most good-naturedly, or sends out a long pear-shaped neck to- wards the horizon. Dr. John Locke took many sketches of the re- markable forms assumed by the sun, and will probably give some ac- count of his observations. The afternoon observations for a time were found to be much affected by the unusual refractions of the at- mosphere of the lake, and evening observations of the stars were found to be utterly useless. Only stars of very high altitude, such as could not be reached by the sextant with an artificial horizon, can be employed for determination of latitude and longitude. This was proved by numerous trials. The morning observations were found to be more reliable, and were exclusively used in our determinations of longitude. It is probable that this extraordinary refraction is limited to the vicinity of the lake. It may be worth while to endeavour to ex- plain the curious phenomena which I have described, and to account for the strange antics performed by the woodland scenery of the lake coast, and of the inverted image of the fisherman's boat as observed. "Lake Superior, being an inland ocean of fresh water in a high northern latitude, (between 46 and 49 north,) has a nearly uni- form and constant temperature, probably not far from the mean tem- perature of the climate. It ranges from 37 to 42 Fahrenheit, never rising above the latter temperature excepting in shallow places near shore. The average depth of the lake is estimated by Bayfield at 900 feet. Its height above the sea is 600 feet ; hence its bottom is 300 feet below sea level. The shores of this lake are much more elevated than those of the other great lakes, and high table-lands ex- tend far back into the interior, and are thickly wooded. The coast, especially on the north side of the lake, is abruptly precipitous di- rectly to the water's edge; and the air on the surface of the lake rarely is of a higher temperature than 50, while that in the forest at noon is frequently as high as 90, or even 94. It is obvious, then, that during a summer's day the air in the forests becomes high- ly rarefied by heat, and takes up a proportional quantity of water in the state of invisible moisture. When this current of warm air slides from the precipices, over the surface of the lake, the warm air by its specific levity from rarefaction floats upon the cooler air of the lake, and does not directly mingle with it. The consequence neces- sarily is, that a Jilm of moisture is condensed at the surfaces of contact NATURAL PHILOSOPHY. 153 of the warm and cold air, and thus a screen is produced on which the objects reflected from below are seen as i:i a mirror. Meanwhile, by refraction, this image is seen higher up than it is really painted on the mist. This was obviously the cause of the strange phantoms which we have witnessed on Lake Superior. It is no uncommon thing on other parts of the Lake to see vessels inverted in the air be- fore their hulls become visible above the horizon ; and it is well known that similar appearances very rarely occur on our sea-coast, and have given rise, in former times, to strange and superstitious tales." Prof. Agassiz mentioned an additional phenomenon, which was frequently witnessed by himself and his party upon Lake Superior. Not only did the shores and islands, with all their vegetation, appear repeated, higher up and in an inverted position, but above this invert- ed landscape there was sometimes still another, in which every thing was upright, so that the picture was twice repeated above the surface of real nature, once inverted, and above that, the same erect. This fact must be explained by any theory which professes to account,for similar phenomena ; but it may be simply the image of the landscape, inverted upon the surface of the lake, reproduced with the inverted image of the landscape itself. HEAT AND EVAPORATION OF THE EARTH. AT a recent meeting of the Geographical Society of Bombay, Mr. G. Buist made an interesting communication on a method adopted by him for ascertaining the heat of, and evaporation from, the soil. The objects and details of the experiment are stated to be as follows : " As the evaporation from a shallow dish of water exposed to the sun, and liable to be raised to a temperature of 100, or 120, gives no idea of the amount of evaporation from the surface of the sea, large pools, or lakes, which vary very little in temperature, he was anxious to determine the amount of evaporation from the surface of wet earth, compared with that from the surface of a considerable mass of water. With this view, two zinc cylinders were prepared, three feet long and four inches in diameter, and secured by a strong brass ring, at the top and bottom, carefully turned. These contained fifteen pounds, or a gallon and a half of water, each, temperature 82, or nineteen pounds of the loose red earth to be found associated with trap-rock. When filled with earth well shaken down, they were able to take in six and a half pounds of water to overflowing. Each was provided with a glass tube, of a quarter of an inch bore, connected with the bottom of a cylinder, and running parallel with it, to the top ; this was intended to show^how high the water stood inside. On filling one of them with earth,' and then adding water till it flowed ^y * ^j over, that in the tube decreased of course rapidly by evaporation, but, strange to tell, after continuing to descend from noon till day- break, it commenced immediately to rise again till 11 A. M., remain- ed motionless till 1 P. M., when it began to sink, and so continued descending, till about an hour after sunrise, when it commenced im- mediately to rise, and so continued till the same hour as during the 154: ANNUAL OF SCIENTIFIC DISCOVERY. preceding day. This had gone on regularly for four days ; each day it sank from two to three inches, and only rose half as much ; the fluctuation was in all respects most perfectly regular and symmetri- cal." London Athejucum, Sept. NATURE OF THE CANDLE-FLAME. 3VL VOLGER has recently subjected the flame of the candle to a new analysis. He finds that the so-called flame-bud, a globular blue flammule, is first produced at the summit of the wick ; this is the re- sult of the combustion of carbonic oxide, hydrogen, and carbon, and is surrounded by a reddish violet halo, the xe.il. The increased heat now gives rise to the actual flame, which shoots forth from the ex- panding bud, and is then surrounded at its inferior portion only by the latter. The interior consists of a dark gaseous cone containing the immediate products of the decomposition of the fatty acids, and surrounded by another dark hollow cone, the inner cap. Here we al- ready meet with carbon and hydrogen, which have resulted from the process of decomposition, and we distinguish this cone from the inner one by its yielding soot. The external cap constitutes the most lu- minous portion of the flame, in which the hydrogen is consumed, and the carbon rendered incandescent. The surrounding portion is but slightly luminous, deposits no soot, and in it the carbon and hydrogen are consumed. Liebig's Annual Report. ARTIFICIAL MOTHER-OF-PEARL. ON the library-table were several curious and beautiful specimens of De la Rue's application of Sir Isaac Newton's thin plates* carved wood, embossed card, plaster of Paris, paper, &c., presenting a me- tallic appearance, but likewise splendid iridal colors, the green pre- dominant. The paper was cut into the form of birds, beetles, &c. ; the varying green shield of the beetle was most natural, and evinced the power of producing any tint or effect required. The material employed for coating the above substances is a colorless varnish, ap- plied by being dropped on water, the specimen to be coated, previous- ly placed in the water, being lifted up against the thin film into which the drop had spread. The colors are due, of course, to the interfer- ence of the luminous rays, the light reflected from the upper in- terfering with that reflected from the under surface ; and upon the ex- tent of the retardation of the luminous waves by such interference, the varieties of colors depend. Mother of-pearl affects light similarly, and thence its lovely hues. White paper, with Mr. De la Rue's coating of varnish, is artificial mother-of-pearl, and a most beautiful representation of it. Proceedings of the Royal Institution. THE FRICTION OF WATER. MR. R. RAWSON has communicated to the British Association at Birmingham, a paper upon the friction of water, containing the result NATURAL PHILOSOPHY. 155 of experiments made by him, their object being to ascertain the fric- tion of the water on a vessel, or other floating body, rolling in it. In making his experiments, he used a cylindrical model, thirty inches long, and twenty-six inches in diameter, whose weight was two hun- dred and fifty-five pounds, avoirdupois. The cylinder was in the first place put into a cistern without water, and made to vibrate on knife edges passing through its axis. A pencil, projecting from the model, in the direction of the axis of the cylinder, on the surface of another movable cylinder, marked out, upon paper placed on this last cylinder, the amplitude, or extent, of each oscillation. The cylinder was deflected over to various angles, by means of a weight, attached by a string to the arm of a lever fixed to the cylindrical model. The table given by Mr. R. shows that in these cases the model vibrated to an angle, in general 6' less than the angle to which it was deflected. When the cylinder oscillated in exactly the same circumstances, except that it was surrounded by salt water, it appears that the angle of vibration was about 30' less than that of deflection. This shows clearly, that when vibrating in water there is a falling off in the angle of about 24' from the vibration out of water. This decrease must be attributed to the friction of the water on the surface of the cylinder. The author thinks, from calculations, that the amount of force acting on the sur- face of the cylinder necessary to cause this decrease is not equally dis- tributed over it, but that the amount on any particular part varies as the depth. Some experiments confirm this view. These, with other experiments, made under the direction of the Admiralty, go to show that when " a sudden gust of wind is applied to the sails of a vessel, or any cause which acts constantly during one oscillation, the ulti- mate amplitude of deflection will be double the amplitude which the gust of wind will permanently deflect the vessel." London Athenaum, Sept. LIEUT. MAURY ON WINDS AND CURRENTS. LIEUT. MAURY is still pursuing his favorite theory of winds and currents, which has already been productive of much good to the commercial world, although the observations as yet made have been very limited compared with those which must be made before a cor- rect knowledge can be obtained of the winds and currents of the dif- ferent oceans. His "Wind and Current Charts" are so made, that" at a single glance the navigator is able to see in what portion of the Atlantic Ocean he shall probably find the most favorable winds and currents. He has adopted the plan of dividing the ocean into sections of five degrees each, and the track of each vessel is laid down across it in colors according to the seasons of the year, and in characters accord- ing to the month, while the symbols for the winds are so contrived that they show at once both its direction and strength. In this way the charts show at a glance the prevailing winds, the temperature of the water, the set and velocity of the currents, the variation of the compass, &e. The results gained by these charts are numerous; we give the most important of them. 156 ANNUAL OF SCIENTIFIC DISCOVERY. It has been discovered that the trade-winds in the North Atlantic blow with more regularity on the American than on the African side of the Atlantic, owing, probably, to the feet that in the latter case the sands and deserts, which heat and rarefy the air, are to the windward, while in the former they are to the leeward. It is also shown that the so-called northeast trade-winds prevail more from the northward on the American than they do on the African side of the ocean, and that calms are much less frequent on this than on that side of the ocean. After carefully comparing the log-books of many thousand vessels sailing between the United States and Brazil, China, the Indies, the Cape of Good Hope, and Cape Horn, the author of these charts has been led to the important discovery that the circuitous course usually taken to these places may be avoided. It may here be remarked that the usual route of vessels bound from our Atlantic coast to the parts of the world named is nearly the same until they reach the equator. But these charts indicate an entirely new route thither. The usual course of our vessels bound to Rio Janeiro, or the Cape of Good Hope, is across the Atlantic Ocean to the shores of Africa, thence to the coast of Brazil, and, if bound to the Cape, a third time across the ocean. This zigzag course has been hitherto pursued, in the belief that, in following it, better winds have been found than if any other had been taken. The fects derived from the log-books and records of a thousand ships show this belief to be unfounded. It has been made to appear that monsoons, or trade-winds, prevail in that part of the Atlantic through which a part of the old route to the equator lies, where no such winds have been thought to exist. From June to November, inclusive, these winds prevail from the southward and westward. And they are exactly in that part of the ocean where, strange though it may appear, vessels, ever since the days of Cook and Cavendish, have been in the habit of going, with the expectation of finding winds favorable for a course to the southward and west- ward. In consequence of results like these, Lieut. Maury was led to ex- amine the materials his industry had accumulated, in order to find a better route. Accordingly, one was discovered and announced, which, besides being several hundred miles nearer, lies also through a region of more favorable winds ; insomuch that the average passage of a number of vessels which have tried this new route during the last year is ten days, or about 25 per cent., less than the average by the usual course to the equator. In consequence of his investigations, Lieut. Maury was induced to recommend a more northerly route than the one usually taken by vessels in the European trade. The ship Wisconsin followed this recommendation on her voyage from Liverpool to New York with great success. She arrived at her port of destination twelve days before two other ships which sailed in company, but which went farther to the south. It is not claimed that such a difference will invari- ably occur in the length of passage by the two routes, but the result is nevertheless full of significance, and indicates the great importance NATURAL PHILOSOPHY. 157 and value to be attached to the subject. If the voyage across the At- lantic can be shortened but a day or two, commerce will still reap im- portant benefits. A still further examination of the materials at his command, has led Lieut. Maury to other promising results. By projecting the courses of large numbers of vessels engaged in the trade of the Gulf of Mexico and noting the currents they have met with, it has been made to appear more than probable that a current has been discovered, which (if found to exist) will shorten the usual sailing distance from Havana to New Orleans, and to other ports in the States bordering on the Gulf, nearly one third. By the route usually pursued, vessels have to encounter an opposing current, running at the rate of nearly sixty miles per day. It is believed that, by following along the Cuba shore, vessels bound to New Orleans will find a current in their favour of equal velocity. In a letter to some citizens of New Bedford, Lieut. Maury enumerates some of his other results. He says that he has ascertained that " the northeast trade-winds form an atmospherical band in the North Atlantic, with surprising regularity of breadth. Were this band opaque, or were it visible to an astronomer in the moon, it would appear to him not un- like the belts of Jupiter do to us, but upon a scale greatly enlarged. Could it be seen by an observer in the moon, he could mark our seasons by it ; so regularly do the materials already furnished show its vibrations up and down in latitude to be according to our months and seasons. This band of northeast trades is not, as has been supposed, parallel to the equator. It is parallel to the ecliptic. The manner in which these conclusions are arrived at admits of no more doubt as to these facts, than there is as to the existence of the trade-winds themselves." Referring to the merchant-vessels, which have been supplied with his charts, he adds, "When these thousand ships return with their observations made simultaneously in all parts of the world, W 7 ho can anticipate the value or the nature of the results to be obtained? When it is blowing a norther in the Gulf, or a tornado in the West Indies, for instance, these observations will enable us to see what it was doing on the other side, across the Isthmus of Tehuantepec. I am beginning to receive returns from this fleet. Our system of observa- tions requires the water-thermometer to be used ; and in consequence it is now beginning, for the first time, to be generally used in the mer- chant service. From the returns already received, this instrument indicates a fork in the Gulf Stream, on the banks of Newfoundland. It also indicates the existence of a cold current setting westwardly between two warm ones running towards the east ; and it indicates, further, the probability of the Grand Banks extending nearly to the coast of Europe. This is all the thermometer can do in this respect ; it can only indicate. Suppose and the supposition is probably not far wrong that the rate of this cold current and of each of these warm ones is one mile the horn- ; vessels do not know where the di- viding line between them is. They lie in the track to Europe ; and if we suppose the average time for which a vessel, on her passage to and fro, is exposed to them to be ten days, we shall see that each vessel 14 158 ANNUAL OF SCIENTIFIC DISCOVERY. may be swept back or carried forward by the current to which she is exposed during that time, 240 miles ; thus making a difference of 480 miles in her progress during onfy ten days of her passage, according as she may have the luck to strike the adverse or favorable current. Would it not be a great advantage to every vessel in the European trade, if she knew exactly where to find these currents, and where to go to avoid the adverse one, and where to take the favorable one ] To ascertain their limits is more than individual enterprise can do, it would require a vessel to be sent there for the purpose, and to em- ploy several months in the examination ; therefore this would seem to be the business of government. " As for your favorite subject, the whales, I am happy to inform you that Lieut. Herndon has them already in hand ; and though his investigations have not yet gone far enough to authorize conclusions, yet there is no doubt in my mind, that, if you will send us well-kept journals, and enough of them, we shall be able to ^construct a chart which will show at a glance in what part of the ocean the whales have been found in quantity in the different months ; and we shall show the parts that are never frequented by them. Take, as an ex- ample : he has examined the logs of vessels which in the years 1833, '34, '35, '39, '40, '44, '45, and '46, cruised 429 days in the square from 5 N. to the equator, between the meridians of 80 and 85 W., and whales were found there in quantities in every month except January, February, and March. In the square from 5 N. to the equator, between the meridians of 90 and 95 W., he has in like manner examined the logs of vessels which cruised there in search of whales 190 days in the years 1832, '33, '34, '35, '36, '39, '40, '41, '43, '45, and '46. Some one of these vessels was there in every month of the year, except December ; and they saw only a few strag- gling whales in February and September. It remains to be seen whether this animal revisits annually the same part of the ocean. So far, it seems probable that he does not ; though it does not appear that he remains in any one part all the year round. What then is to regulate his visits from place to place ? Probably the abundance of food ; therefore this is a subject to which I would invite particular attention. What is the food of the whale ? What localities and what temperature of the water are most favorable to its production 1 How long does it take to mature ? Satisfactory replies to these interrogato- ries would throw much light upon the subject. " The observations, in addition, required for this work are the lati- tude and longitude of the ship, the temperature of the air and water, and the set of the current daily ; the variation of the compass as often as it is observed, and the prevailing character of the wind for every eight hours of the twenty-four, stating always the point of the com- pass whence it blows. Besides this, the mention of whales, large quantities of sea-fowl, drift, tide-rips, discolorations of the water, fogs, rain, thunder and lightning, whenever they occur or are seen, with any other remarks that may be deemed of general interest, should be entered in the journal kept for this office. Care must be taken to note in it, also, the kind of whale, whether right or sperm." NATURAL PHILOSOPHY. 159 Perceiving the importance of the results likely to be obtained, the late Secretary of the Navy authorized these charts to be given to every navigator, who would return to the National Observatory, ac- cording to a form, an abstract of his voyages. Several thousand sheets of the chart have already been distributed upon these terms; and there are now engaged, in all parts of the Atlantic Ocean, hun- dreds of vessels, making and recording observations. Thus it will be seen, that in the course of two or three years the system will prob- ably be nearly perfected, and to this time all intelligent navigators look forward with much interest. Another result already obtained is, that, by examining the manner in which the charts are cut up by the tracks of vessels, Lieut. Maury is enabled to assert confidently, the non-existence of a number of rigias, and other dangers of doubtful position, which disfigure our most accurate charts. OCEANIC CURRENTS. WHILE Lieut. Maury is developing in this country a series of charts, showing the actual winds and currents of the ocean, a French saian, using like him, the results discovered by others, is endeavour- ing to assign a cause for these currents. M. Babinet has communi- cated to the French Academy an hypothesis with reference to the universal law of currents, W 7 hich he supposes to hold good in the main, though it will be found to be often modified by a great many accidental circumstances. M. Babinet is not a seaman, but having carefully studied Dnper- ry's " Chart of Oceanic Currents," and observed many other phenom- ena of physical geography, he has built on them the following hy- pothesis : The equatorial zone of the ocean is naturally much broader than the others, therefore it expands and overflows itself to both poles, while the water at the poles flows to the equator to re- store the equilibrium; but owing to the revolution of the earth on her axis, the velocity of the water strata, under the equator, is much greater than that of those north and south of it, while the latter have a lesser path to describe. It results from this, that the waters which flow from the equator have an inclination to advance before the motion of the earth, whilst those which come from the poles have a tendency to remain behind the motion. If we cast a glance over the formation of the several continents, the ocean will be found divided into a certain number of basins, in which the force of this law still endures; each basin has an eastern and western shore, and is inclosed on the other side, by the equator and a boundary which may reach to the pole. If the water which comes from the pole to this point attains to the equatorial boundary, then it is behind the motion of the earth, which goes from east to west; the counterpart is found on the boundary opposite the pole, and to complete the course, the water which flows from the pole runs along the western boundary, and that which returns to the equator runs along the eastern boundary. Let us cast a glance on the map of the earth, 160 ANNUAL OF SCIENTIFIC DISCOVERY. and it will be seen that the great ocean is divided into five principal basins. The Atlantic contains two, separated from one another by the equator; the Pacific contains two also separated from one an- other by the equator ; the other is formed by the Indian Ocean, lying between India and Australia. Two circumpolar currents may also be perceived, one of which goes round the north pole, and the other round the south pole from east to west. The theory speaks of certain tracts of water in the middle of each of the basins, where the fluid remains motionless, and where no current exists, shown in the chart by the absence of the arrows marking the direction of cur- rents. Similar but much simpler operations are going on in the at- mosphere, producing trade-winds and their counter currents, the cause of which has long been known, and M. Babinet has been led through them to the present solution of the oceanic current phenom- ena. This double circulation of air and water possesses great influ- ence in the mitigation of the climate, and the consequences would be inconceivable, if, as in the Ptolemaic system, the earth were to stand still, and the sun to revolve round her, for the revolution of the earth on her own axis, and round the sun, is one of the most important elements in the terrestrial system. THE WATER-THERMOMETER. LIEUT. MAURY states that he has been very much assisted in de- veloping his theory of winds and currents by means of the thermom- eter used by some vessels for determining the temperature of the water. It was by means of these observations on the temperature of the water that he was enabled to prove that off" the shores of South America, between the parallels of 35 and 40 S., there is a region of the ocean in which the temperature is as high as that of our own Gulf Stream, while in the middle of the ocean and between the same parallels the temperature of the water is not so great by 22. Now this very region is noted for its gales, being the most stormy that the as yet incomplete charts of the South Atlantic indi- cate. Lieut. Maury says, however, that very few navigators make use of the water-thermometer, so that he has experienced some in- convenience in his undertaking. He is the more surprised at this, from the fact that New York owes much of her commercial impor- tance to a discovery that was made by this thermometer. At the time when Dr. Franklin discovered the Gulf Stream, Charleston had more foreign trade than New York and all the New England States together. Charleston was then the half-way house between New and Old England. When a vessel in attempting to enter the Delaware or Sandy Hook met a northwest gale or snow-storm, as at certain seasons she is apt to do, instead of running off for a few hours into the Gulf Stream to thaw and get warm, as she now does, she used to put off for Charleston or the West Indies, and there remain- ed till the return of spring before making another attempt. A beau- tiful instance this of the importance and bearings of a single fact, elicited by science from the works of nature. NATURAL PHILOSOPHY. 161 THE BUOTANCr OF THE WATER OF THE DEAD SEA. " ABOUT sunset, we tried whether a horse and a donkey could swim in the sea without turning over. The result was, that although the animals turned a little on one side, they did not lose their balance. A muscular man floated nearly breast-high without the least exertion. A horse taken into the bay could with difficulty keep himself upright. Two fresh hen's eggs floated up one third of their length ; they would have sunk in the water of the Mediterranean or the Atlantic. The water of the sea was very buoyant ; with great difficulty I kept my feet down ; and when I laid upon my back, and, drawing up my knees, placed my hands upon them, I rolled immediately over." "Tried the relative density of the water of this sea and of the At- lantic, the latter from 25 north latitude, and 52 west longitude ; distilled water being as 1. The water of the Atlantic was 1.02, and of this sea 1.13. The last dissolved one eleventh, the water of the Atlantic one sixth, and the distilled water five seventeenths of its weight of salt. The salt used was a little damp. On leaving the Jordan we carefully noted the draught of the boats. With the same loads, they drew one inch less water when afloat on this sea than in the river. Since our return, some of the water of the Dead Sea has been subjected to a powerful microscope, and no animalcules or ves- tige of animal matter could be detected." Lieut. Lynch's Expedition to the Dead Sea and the Jordan. TO SEPARATE POTATOES OF DIFFERENT QUALITIES. WE learn from the London Patent Journal that Mr. James Ander- son, of Glasgow, has secured a patent for a plan for the seemingly in- significant purpose of separating potatoes of different qualities, but the method adopted merits attention. According to experiment it was found that a potatoe containing 20 per cent, of solid nutriment was about the specific gravity of 1.080, that is, taking distilled water at 52 as unity, while the same root with 30 per cent, of nutriment is of a specific gravity of 1.120. Taking this rule, which the patentee found to be invariably correct, he is enabled to divide the vegetables into two or more distinct classes. For this purpose he places them in a vessel containing water brought to a density suited to the quality of the article, which is easily effected by adding salt or clay to the water, and then those which are of less specific gravity will float, while the heavier ones will sink. These two qualities may be again immersed in liquids of different specific gravity, and so again subdivided. li* CHEMICAL SCIENCE. RECENT CHEMICAL DISCOVERIES. M. PASTEUR, of Paris, has availed himself of the beautiful discov- ery of M. Biot, of the influence of chemical composition in altering- the rotation of polarized light, to show that the tartrates and paratar- trates differ from each other only in the form of their crystals. M. Ossian Henry has communicated to the Paris Academy of Sciences a memoir upon the existence of two new bodies belonging to the amide series, one a limpid yellowish oil, lighter than water, and disengaging a strong and penetrating odor, which he considers a bi- sulphuret of amidogen, the other a delicate yellow oil, which, when burnt, gives out an alliaceous smell, combined with a citron-like odor, which he regards as a sulphocyanuret of amidogen. In the Brussels Academy, M. Louyet has given the results of some experiments on the passage of hydrogen gas through solid bodies, by which he shows that this subtile gas passes with facility through paper, and even through leaves of gold and silver. By directing a stream of the gas on one side of the leaf, it may be lighted on the oth- er. As proving the extreme tenuity of the gas and the porosity of the metals, this is important. Anhydrous nitric acid, which has not hitherto been procured by chemists, has at length been prepared by M. Deville, of Besancon, France, by passing perfectly dry chlorine over equally dry nitrate of silver ; no action takes place at ordinary temperatures, but the nitrate must be heated at first to 203 Fahr., and then lowered to 140 or 150; the decomposition then proceeds quite regularly. At first hyponitrous acid is formed, but on lowering the temperature the new substance is deposited in crystals, in the cooled part of the apparatus ; although a cold of 6 was employed to condense the vapors, the crystals were found to form when ice alone was used. The vapor of the anhydrous nitric acid penetrates caoutchouc tubes with such ease, that it is necessary that all parts of the apparatus through which it passes should be solidly joined. The anhydrous nitric acid forms large, bril- liant, colorless crystals in six-sided prisms of the trimetric system. CHEMICAL SCIENCE. 163 The melting point is 85, the boiling 1 point 113. With water much heat is evolved, and solution takes place without the escape of gas; the solution forms nitrates. Decomposition takes place so near the boiling point of the crystals, that the density of the vapor cannot well be determined. On attempting to recrystallize the substance in a sealed tube, in which it had been suffered to liquefy, a violent ex- plosion took place. LIQUID PROTOXIDE OF NITROGEN. M. DUMAS has recently communicated to the Paris Academy of Sciences an account of the method used by him in effecting the liquefaction of large quantities of protoxide of nitrogen. He used a force-pump constructed for the purpose, securely bound with a belt of iron. He so arranged it that, the reservoir being surrounded by ice, the body of the pump was cooled by a circulation of water around it, and even the stem of the piston was always moistened by cold water. He then compressed into the reservoir in the course of two hours 200 litres* of gas, of which 20 suffice to produce a pressure of 30 atmospheres, about which liquefaction commences. The remain- der of the gas furnishes a liquid. Once compressed, the liquid gas may be preserved in the reservoirs for a day or two, but if the stop- cock is opened the gas escapes, and a portion freezes at first, but soon flows in a liquid state ; the solid portion resembles a mass of snow. It melts upon the hand, and rapidly evaporates, leaving a severe burn. The liquid portion, which is far the most abundant, if received in a glass keeps for half an hour, even in the open air. The protoxide of nitrogen is liquid, colorless, very mobile, and perfectly transparent. Metal dropped into it produces a hissing noise like that of red-hot iron plunged in water. Quicksilver causes the same noise, freezes, and affords a hard brittle mass resembling silver in color. Potassium floats upon the liquid and experiences no change, and the same is the case with charcoal, sulphur, phosphorus, and iodine. Ignited charcoal floats and burns with brilliancy. Sul- phuric acid and concentrated nitric acid freeze. Water is converted to ice with a slight explosion. SiMmaris Journal^ July. AN ANCIENT ART REDISCOVERED. AT a late meeting of the Asiatic Society of London, a human hand and a piece of beef preserved by means of a preparation of vegeta- ble tar, found on the borders of the Red Sea in the vicinity of Mocha, were presented ; a specimen of the tar accompanied them. Col. Hold, who presented the specimens, observes, " During my resi- dence on the Red Sea, a conversation with some Bedouin Arabs, in the vicinity of Mocha, led me to suspect that the principal ingredient used by the ancient Egyptians in the formation of mummies was nothing more than the vegetable tar of those countries, which is called by the Arabs Katren. My first trials to prove the truth of this conjecture * Litre equals 0.220097 parts of British imperial gallon. 164 ANNUAL OF SCIENTIFIC DISCOVERY. were on fowls and legs of mutton, and, though made in July, when the thermometer ranged at 94 in the shade, they succeeded so much to my satisfaction, that I forwarded some to England, and have now the pleasure to send to the Society a human hand prepared in a similar way four years since. The best informed among the Arabs think that large quantities of camphor, myrrh, aloes, and frankincense were used in the preparation of the mummies. These specimens will, however, prove that such additions were by no means necessary, as the tar ap- plied alone penetrates and discolors the bone. This tar is obtained from the branches of a small tree or shrub, exposed to a considerable degree of heat, and it is found in most parts of Syria and Arabia Felix." NEW METHOD OF PREPARING- SULPHURIC ACID. IT has been generally supposed that the elements of sulphuric acid will not combine in a direct manner, and that the presence of water is necessary to insure its formation. Prof. Davy has lately shown that this is an error; and by the following experiment, made before the Royal Dublin Society, he demonstrated the practicability of form- ing sulphuric acid directly from its elements. Having placed in a dry Florence flask some sulphur, he vaporized it by the application of heat, and then ignited the vapor by means of a red-hot iron rod. The combustion extends throughout the vessel ; at the instant of its taking place, both sulphuric acid and sulphurous acid are formed, the former descending in condensed drops, and the latter escaping from the flask. Prof. Davy hopes to render his process available in the manu- facture of oil of vitriol. CHLOROFORM. Two French chemists have made a minute examination of chloro- form and have communicated the results obtained to the Journal de Pliar- macie et de Chimie, and it is from this that we derive the following statements. In commerce two liquids are known under the name of chloroform, which are of different origin, but are considered identical, and are often substituted for each other. There are, however, con- siderable differences in their properties ; one, which may be called the normal chloroform, being derived from the reaction of hypochlorite of lime upon alcohol, while the other comes from the action of the same substance upon pyroxylic spirit, and differs very much from the first. That derived from pyroxylic spirit, which the authors conditionally call methylic chloroform, although it has the same appearance as the other, has a very different odor, being not sweet and agreeable, but nauseous, and having a burnt or empyreumatic smell. Its density is also less than that of the normal chloroform, and its boiling-point not so high, and its inhalation is far from pleasant, often causing general uneasiness, followed by heaviness of the head, continued nausea, and sometimes vomiting. On examination it was found that the two chloroforms are in reality identical, but that there is in the methylic variety a considerable quantity of foreign matter of an oily con- sistency, which is composed of several substances, and which it is CHEMICAL SCIENCE. 1G5 impossible at present wholly to expel. This oil is extremely hurt- ful to the animal economy, so that the normal chloroform is the only one proper for inhalation, and even this should be carefully rectified by distillation, as it often contains foreign substances, which produce the same effects as the methylic chloroform. COMPARATIVE EFFECTS OF ANESTHETIC AGENTS. DR. C. T. JACKSON, at the meeting of the Boston Natural History Society, April 4th, laid before the Society the results of his obser- vation on the comparative effects of the inhalation of nitrous oxide, the vapor of chloroform, and sulphuric ether. Nitrous oxide, he said, administered in large doses, produces great excitement, which in- creases with the quantity inhaled. The vapor of chloroform, on the other hand, when inhaled rapidly, causes an immediate and entire prostration. The same is true, in a less degree, of sulphuric ether. They do not produce the intoxication which is caused by nitrous oxide, and this agent also, when administered slowly, fails to produce the usual effects. The vapor of chloroform, slowly inhaled, has an injurious influence, disorganizing the blood, and stopping the circula- tion in the capillaries. When suddenly introduced it retards, but does not stop, the circulation. Patients to whom it is slowly admin- istered recover slowly, and it is important in all cases that enough air should be admitted with it. Persons inhaling nitrous oxide retain the sensibility to touch, and respiratory action is quickened, increases, and becomes deeper as the inhalation is prolonged. During the in- halation of chloroform and ether, on the contrary, the respiratory action diminishes. Under the influence of exhilarating-gas the sys- tem is made very irritable. Dr. Jackson thought that the few cases of excitement after the inhalation of ether might be attributed to the previous state of mind of the patient, or to alcohol combined with it. Conclusions drawn from experiments upon animals with these agents, should be received with great caution, for their action on animals differs according as these have or have not a cutaneous o perspiration. It kills those of the latter class. Dr. Jackson recom- mended a mixture of chloroform with alcohol, in the proportion of an eighth or a quarter of an ounce of the former to four ounces of the latter. Dr. Warren remarked, that from his o\vn experience he preferred ether to chloroform, as being much safer, and in his own practice used chloric ether in preference to either of the other anaesthetic agents. USE OF ANAESTHETIC AGENTS DURING SURGICAL OPERATIONS. STANISLAS JULIEN has found, in examining the Chinese books in the National Library at Paris, the proof that the Chinese have been long acquainted with the use of anaesthetic agents during surgical opera- tions. The extract which he gives is from a book published about the commencement of the sixteenth century, in fifty volumes quarto, 166 ANNUAL OF SCIENTIFIC DISCOVERY. and entitled, " Kou-kin-i-tong" General Account of Ancient and Modern Medicine, and refers to the practice of a celebrated phy- sician, Ho-a-tho, who flourished between the years 220 and 230 of our era. It states, that, when about to perform certain painful opera- tions, "he gave the patient a preparation of hemp," (Hachich), and that at the end of a few moments "he became as insensible as if he had been drunk or deprived of life." After a certain number of days the patient was cured, without having experienced the slightest pain during the operation. In a subsequent notice he also shows that the same physicians use the hydropathic system as a cure for certain dis- eases; among others, chronic rheumatism. Comptes Rendus, Jan. 29. NAPHTHA VS. CHLOROFORM. PROFESSOR SIMPSON has been testing the properties of naphtha, which seems to be as good as ether for inducing temporary insensibi- lity. Professor S. administered the naphtha to two patients, a man and a boy, on whom Mr. Milter performed the painful operation of ex- tracting portions of necrosed bones from the tibia, by perforating the newly-formed shell with the trephine, and removing the sequestra with the forceps. The sleep induced was deep and tranquil, and the breathing was less stertorous than when chloroform is employed ; but it was remarked, that the effect of the naphtha upon the heart's action was much greater, the pulse becoming extremely rapid and flut- tering, thus rendering it less safe as an anaesthetic agent than chlo- roform. INHALATION OF HYDROGEN GAS. M. VAN ALSTEN, of Rotterdam, has recently fallen a victim to his devotion to science. He was the author of a work on chemistry, and was desirous before finishing it of testing to what dem-ee a man iniuht o o c^ without danger inhale hydrogen gas. He tried the experiment on his own person, and, in spite of all the exertions of his physicians, he died in a few hours. Atlienccum, June. NEW METHOD FOR THE EXTRACTION OF SUGAR FROM SUGAR- CANE AND BEETS. THE most extraordinary and valuable discovery which has been made during the year 1849 is undoubtedly that of M. Melsens, Pro- fessor of the State Veterinary and Agricultural College of Belgium, relative to the extraction and clarification of cane or beet sugar. The success which has attended this gentleman's experiments has caused the greatest sensation among the manufacturers and statesmen of France and Belgium. This could not be otherwise in countries where so large a capital is invested in the growth of beets, and the manufacture of sugar from them, in the refining of exotic sugar, and the important collateral interests to which they have given rise. A committee of the most distinguished scientific men of France and CHEMICAL SCIENCE. 167 Belgium were appointed by the two governments, and in their pres- ence experiments were made which tested the efficacy and value of the new method. The process for some time was kept secret, but M. Melsens having obtained a patent from the French and Belgian gov- ernments, a memoir has been published revealing the essential facts of the discovery and its method of application. The importance of this discovery and its bearing upon the interests of this country, induced Hon. S. G. Clemsen, Charge d? Affaires of the United States at Bel- gium, to transmit to the Secretary of State a full translation of the memoir. The following condensed and popular account of the discovery, with remarks on the same, we copy from the New York Journal of Commerce. " In the phenomena of the crystallization of sugar, we encounter a series of anomalies which have baffled the efforts of the greatest chemists, to reduce the incoherent facts to a consistent theory. Ber- zelius, Dumas, Proust, and other names known in the higher walks of practical science, are associated with investigations into the elementary properties of saccharine juice, and the most effective method of turn- ing those properties to advantage, in the manufacture and extraction of solid sugar. Although the improvements made in this branch of the industrial arts, within the present century, have been numerous and great, they have been very far from approaching the point of excel- lence attained by other arts, concerned in supplying the luxuries, wants, and necessities of mankind. In fact, it has long been recog- nized that, among the arts of production, it was in the manufacture of sugar that there remained to be taken one of those strides, which im- mortalize a name, and signalize an epoch. This stride has recently been taken by a young Belgian chemist, of the name of Melsens, pro- fessor in the Veterinary and Agricultural School of the State, at Brussels. It is a certainty that Melsens' discovery is destined to ex- ercise an influence upon the production of one of our national staples, which will be attended with a vast accession of national wealth. The principal features of this discovery may be compressed into a small space. " It is a well-established fact that the sugar-cane, when in a heal- thy condition, contains no sugar that is not crystallizable. It is also known that the extraction of this solid is easily effected by means of weak alcohol, which first dissolves it, and then leaves it, by evapora- tion, in the form of pure and colorless crystals. But, together with crystallizable sugar, there also coexist in the cane certain fermenta- tives capable of determining a transformation of the sugar into other products. The action of these agents is only rendered possible by placing them in' contact with the sugar by means of water, after hav- ing been previously exposed to the influence of the external air. "In bitter almonds there also exists a substance which may be crystallized by alcohol without losing its purity. But the effect is en- tirely different when water is used in the place of alcohol. This sub- stance found in bitter almonds (amygdaline) disappears or undergoes a metamorphosis, and by the change various new substances are 168 ANNUAL OF SCIENTIFIC DISCOVERY. formed entirely different from the original. That water should have this effect, it is necessary that it should come in contact with the air, and that it should encounter ad dissolve certain fermenting sub- stances which are found in the tissue of the bitter almonds, with the amygdaline. " The rapidity with which the cane juice, in warm climates, under- goes alteration, is the great obstacle to the extraction of the pure solid, and the great cause of loss in the process. The chemist, in his labo- ratory, solves the problem of the extraction of sugar, by the employ- ment of alcohol. This agent, without producing the slightest alteration in the properties of the sugar, separates it from its associated substances, and protects it from every destructive influence. Alcohol, however, will not answer the purposes of practical industry, which require the em- ployment of an agent low in price and of easy application. Such an agent alcohol is not ; it is costly and dangerous as a combustible. But is it beyond the resources of chemistry to discover a liquid which, like alcohol, will separate the sugar and prevent the fermentation which, in the manufacturing processes now in use, ensues as a consequence of the contact of the juice with the external air? Such \>as the question Melsens proposed to himself, and which he has answered triumphantly by the production of the agent. " It was step by step, by an infinite series of experiments, and by the concentrated direction of a thoughtful and educated intellect, that Melsens succeeded in detecting and bringing to the light of day what had escaped the scrutiny of Dumas and Berzelius. The first small fact upon which he proceeded was, that, in the tissues of the cane, sugar is found dissolved in water, and it will remain there in a state of preservation for a considerable length of time. From this fact, it was legitimate to infer, that if water could be used as a solvent, the conditions accompanying its presence in the tissues being retained, the saccharine substance could be extracted unaltered. The difficulties, therefore, attending the extraction are not connected with the sugar or the water, but with the air, and the fermentatives which its contact develops. This being the case, were it possible to crush the cane in xacuo and to express the juice and boil it in xacuo, either for the pur- pose of purifying or evaporating, nothing would remain to be desired. But this is not possible, at least upon a large scale. Melsens was thus urged to the discovery of an agent absorptive of air, hostile to fermentation, innocuous to man, low in price, and easy of production. Such an agent he found to exist in the bisulphite of lime. " Melsens' experiments with this agent were made upon a dozen varieties of juice, including beet-root juice, or pulp, grape juice, and cane juice. The results were uniform ; the sugar crystallized without loss, without trouble, and without the production of molasses. The earlier experiments demonstrated that the bisulphite of lime, em- ployed as a body absorptive of oxygen, and as an antiseptic, had no injurious effect upon the sugar, if applied cold, and in such a manner as to mix with the juice at the very moment of the rupture of the cellular tissues; and further, that in its presence the action of heat CHEMICAL SCIENCE. 169 required for purification became perfectly innocuous. In the latter operation, the lime employed caused the bisulphite to disappear by neutralizing it, leaving the juice purified and free from fermentatives, and from all matters capable of producing them. The juice thus pre- pared was ready for evaporation without any loss of sugar. " But the bisulphite of lime was soon discovered to possess other qualities of a peculiar character. With the antiseptic property, and the property of absorbing the oxygen gas of air, it unites the proper- ties of a powerful purifier. Heated to 100, French measurement, it separates the albumen, the caseine, and matters containing nitrogen, all of which are found to exist in a natural state in saccharine juice. The separation is eifected without loss, and without any appreciable transformation of the sugar. It remained to be ascertained how far the bisulphite was effective in opposing the coloring of saccharine liquids. The coloring of the saccharine juices of the cane proceeds from four principal causes: 1. The cane itself contains colored matter, which becomes dissolved in the juice. 2. The contact of the juice with the air rapidly engenders colored substances, which unite with the preceding. 3. The heat employed in evaporating, by altering a part of the sugar and of the products which accompany it, also forms color- ing matter. 4. The contact of the air and of the lime, and also of the ammoniacal gases, assisted by the action of the heat, produces coloring matter during the evaporation of the juices when alkalized by lime. " The bisulphite of lime almost instantaneously extracts the color of the colored matter which exists in the cane from natural causes ; it prevents the formation of the colored matter which the air produces by its contact with the juice ; and prevents the production of that which is engendered during evaporation, and especially of that which requires for its formation the concurrence of the air and of a free alkali. The effect attending the use of the bisulphite, as an agent capable of resisting the formation of color, is so remarkable as to de- serve the attention of persons employed in many branches of the pro- ductive arts. There is no doubt that the cases are numerous in which it can be employed in the most efficacious manner, in preventing the formation of those coloring matters, which, when once formed, it is found so difficult to destroy or extract. Such matters, for instance, are those which color hemp-yarn and flax, indigo after precipitation, the juice of barks used in tanning, and the extracts of certain dye- woods. .Meanwhile, Melsens has established that, in the process of evapor- ating without the application of artificial heat, the presence of the bi- sulphite effectually opposes the formation of coloring matter, and that where the evaporation is effected by the application of artificial heat, the coloring matter formed is scarcely perceptible. " Although we have omitted many details, we have exhibited enough to show that bisulphite of lime can be employed in the operation of extracting sugar from the cane, 1. As an antiseptic of superior ex* cellence, preventing the production and action of fermentatives of whatever kind. 2. As an agent absorptive of oxvgen, capable of 15 170 ANNUAL OF SCIENTIFIC DISCOVERY. preventing the alterations occasioned by the presence of the latter in the juice. 3. As a purifying agent, which, at 100 degrees, will clari- fy the juice and separate from it all albuminous and coagulating sub- stances. 4. As an agent capable of expelling preexisting colors. 5. As an anti-colorant, capable of effectually preventing the formation of coloring matter. 6. As an agent capable of neutralizing the injurious acids which may be found existing, or may be engendered in the manu- facture. "The questions that next presented themselves for investigation were, in what proportions, and under what forms, the bisulphite of lime should be applied, what inconveniences, balancing its promised ad- vantages, might attend its use. To enable himself to answer these questions satisfactorily, Melsens procured from the province of Murcia, in Spain, where for ages sugar from the cane has been manu- factured, a quantity of ripe canes. They reached Paris in good condition, and were deposited in the laboratory of the Sorbonne, where the experiments were being prosecuted. A number of persons con- versant with the manufacture of sugar in the colonies were pres- ent at the first essays. The results were such as to fill them with surprise. The juice was extracted by crushing the cane in a com- mon mortar previously supplied with the bisulphite. It was puri- fied by ebullition, and then passed through a piece of cloth. The syrup, after being concentrated and filtered a second time, was left to slow crystallization. The sugar obtained by this simple process was as excellent in quality as could have been obtained by the use of alcohol. " The experiments tried in Paris upon the cane-juice demonstrate that the employment of the bisulphite secures the extraction of all the sugar contained in the cane, and produces it in a solid and crystallized form. The crystals are large and firm : they are not more colored than common candy, of which they have the appearance, and they exhibit no appreciable traces of the slightest alteration being effected in the saccharine properties. If, therefore, we take into consideration the almost absolute purity of the cane-juice, which is in reality nothing but sugared water, when purification has once been effected, and if we also take into consideration the special aptitude of cane-sugar to as- sume the form of large crystals, it would seem almost certain that the first planter who will submit a quantity of syrup to slow crystallization, by Melsens' method, will obtain crystals exceeding in size and quan- tity, and excelling in whiteness and appearance, all previous expe- rience. " But we have not done with the advantages that will attend the introduction of this new agent. It is well known that the juice ex- tracted from the cane by means of pressure is but a small proportion sometimes only a half, and at most two-thirds of what might be extracted. There remains, therefore, behind, a third or more of the natural yield of the sugar-crop, and this third becomes, we be- lieve, a total loss. The extraction of the sugar, thus wasted, by sim- ply washing with pure water, is not to be thought of. The air, the heat, the fermentatives, and other causes, contribute to establish a CHEMICAL SCIENCE. 1*71 rapid fermentation, and no gain can be derived from the operation. But, by Melsens' process the difficulty and waste are obviated. With water containing a small quantity of the bisulphite, not only may the washing be effected with ease, but at the leisure of the planter. Hours or days, at his will, may be employed in this operation, now, perforce, neglected altogether. The saccharine washings will be found nearly as rich in sugar as the juice proves, and if treated in the same manner, by purification, by simple filtration, and by concentra- tion in the free air to the consistency of syrup', crystallization will en- sue with equal certainty and success, the product being in all re- spects similar and equal to that obtained from the juice itself. " A comparison of the methods actually in use, in the extraction of sugar from saccharine juices, with that prescribed by Melsens, will assist in the formation of a correct appreciation of the superiority of the latter. " By the present methods, the crushing being operated under ex- posure to the air, the alterations attending it render rapidity of exe- cution indispensable. But, however rapid the execution may be, it does not, and cannot, prevent alterations from taking place. Again, the purification effected by means of lime develops and stimulates the formation of coloring matter, and compels the employment of ani- mal black. Finally, the process of evaporation, which is effected at a high temperature, modifies a portion of the sugar which the heat renders uncrystallizable. From this results the necessity of resorting to repeated operations, and to four or five successive crystallizations, which are never comple