consist of an organic and a nitrogenized substance, which the author has now under examination.

Various Communications.In the name of a Commission consisting of MM. Thenard, Balard and General Piobert, M. Balard read a very favorable Report on the researches of M. Violette on the carbonization of wood by means of over-heated steam, of which we gave an account in the number for September, 1853.-M. Payen read a memoir, demonstrating the presence of carbonate of lime in vegetables.-A naval officer, M. Tramblay, read a paper on a new apparatus for saving property at sea.--M. Thomas, of Colmar, presented an arithmometer upon which he had worked for thirty years, which, as appears, resolves completely the problem of calculating machines: we shall return again to it.-At each session of the Academy, communications flow in from the four quarters of the globe both on the subject of the Bréant legacy (100,000 francs, to the person who shall discover the cause and cure of cholera), and that of the prize proposed respecting the disease of the vine. The largest number of communications come from Germany. This earnestness is no doubt praiseworthy, and yet may excite a smile; for each of the authors pretends to have resolved the problem better than all others, and the number of panaceas discovered or announced now amounts to thousands.

In the year X. of the first Republic, the French Government founded a prize of 60,000 francs, to be given to the person who should through experiment and discovery, make a step in electrical science comparable with that of Franklin and Volta, to be adjudged by the Academy of Sciences. The fact of this offer has recently been called to mind by Madame Ersted, who claims the prize in the name of her late husband, M. Ersted. A commission consisting of MM. Pouillet, Becquerel, Despretz, Thenard and Regnault, have been charged with the examination of this demand. They find much embarrassment, since without contesting the merit of Ersted's discovery, his is not the only important one made since the year 1801. The discoveries of Davy, Ampère, Arago, Faraday, Ohm, Morse, Wheatstone, Jacobi, the pile with a constant current discovered by M. Becquerel, the thermo-electric cur rents discovered by Seebeck,-all show that it would have been far easier to have awarded the prize in 1820 than at the present time.

Industrial Photometry.-An instrument by Mr. Babinet for exact photometric measurements, has for a long time been used, which is based on the neutralization of the tints of polarized light, as employed in photometry by Arago. We have not space for a figure and complete description of this small apparatus, which the ingenious Duboscq has rendered very portable and convenient for use. It consists essentially of a tube having a ground glass at one end, and at the other end an analysing prism of Iceland spar. A pile of plates of glass, serving as a polarizer is fixed to the tube so as to form with it an angle of 35°, the angle of polarization of the glass. The light diffused upon the ground glass, reaches the eye only after having passed across the pile of glass, and is consequently polarized by refraction perpendicularly to the plane of incidence of the rays.

The ground glass is for receiving the illuminations for comparison. It is successively illuminated by the lights to be compared. On traversing the pile of glass plates, the rays are brought into a condition to

color the four semicircles of a Soleil's polariscope, which is furnished with plates, having the property of double rotation. By means of a third source of light, a second ground glass is illuminated, which is placed obliquely so as to neutralize the colors produced by one of the luminous sources under comparison; then leaving this light fixed with relation to the instrument, the photometer is moved towards or from the second source of light, until the colors disappear anew. The relation of the square of the distances give, then, the relation between the intensities of the two lights. Different precautions are necessary when it is not convenient to vary the distance of the photometer from each of the sources of light, as, when they are two jets of gas, or of electric light, not easy of access. But it is impossible here to enter into these details.

On forming vessels of gold by the aid of phosphorus.-The property of phosphorus, of precipitating certain metals from their solution has long been known; and gold is among the number. M. Levol has used this process in forming gold vessels useful in chemical research. He takes the perchlorid of gold, and places in it, at the ordinary tempera. ture, some phosphorus, moulded of a form convenient to serve as a nucleus for the vessel of gold. To give the phosphorus the desired shape, it is melted in a water-bath near 60° C. in temperature, within a vessel of glass having the form required. After cooling it, the phos. phorus is taken out solid, from its envelop, breaking it, if it be neces sary. The precipitation of the gold or the construction of the vessel is then begun; and it finally remains only to remove the phosphorus by re-melting it and washing by the aid of boiling nitric acid until the last traces are removed.

Gilding of Silk, &c.-Commerce has furnished for some time a kind of silk treated by a galvanoplastic method; the threads produce a costly fabric of wonderful solidity. The author of the process is M. Pouilly. He first metallises the silk, then covers it with a thin layer of copper and finally applies the gold by the aid of the galvanic battery.

Similar trials have been made within a few years by Madame Foa. The gold is dissolved in aqua regia, then dried by evaporation, then it is dissolved again in water, which is diluted with a large quantity of distilled water. The fabric under treatment was placed in this bath; the salt of gold fixes itself upon the ligneous fabric, and the compound is reduced by an exposure of the tissue to the action of hydrogen. This process has been abandoned, as it proved to be not uniformly successful, though without reason, as success once is enough to insure constant success after the causes of failure are studied out.

Local anesthesis.-The process invented by Mr. Harris enables the surgeon to render insensible the part of the body to be operated on, without affecting the rest of it. MM. Nélaton and Paul Dubois, two skillful surgeons of Paris have made with the apparatus the following experiments. After having for five minutes directed a jet of the vapor of chloroform on an abscess, Dr. Nélaton was enabled to make an incision into the hollow of the foot without the least sign of pain on the part of the person operated on. The following fact observed by Dr. Dubois is still more remarkable. A young woman had an abscess in * armpit and an ulcer on the wrist. She suffered much from both d not use her arm. The first application of chloroform was the armpit. The tumor, although so painful that she could

not bear to have it touched, became so completely insensible, that it could be handled without pain, and the woman could raise her arm; the insensibility continued for three hours. The operation was not performed that day. When the abscess was at its head, the chloroformic fumigation was renewed, and almost immediately Dr. Dubois plunged the knife into the abscess without any sensation on the part of the patient; he then turned her attention from it, and after this there was no more feeling of pain in the region. Afterwards the small place on the hand, fumigated in the same way, also remained completely insensible. These facts are strongly affirmed by two honorable physicians who also cite the witnesses to the operations. Other doctors have attempted to repeat the experiment; but, as is singular, without success. More study of the conditions necessary may lead to new and complete success; and we hope to announce such in our next communication.

Influence of bismuth on the ductility of Copper.-There has recently arrived from Australia a black copper in ingots possessing some peculiar properties. Although of high per-centage the color is bronze; it is but little ductile; the fracture is loose and crystalline, which may be removed by refining according to the ordinary methods.

M. Levol, Assayer at the Mint of Paris, has analyzed this copper before and after refining, with the following results:

0.041167

0.008917

Loss, The lead and trace of arsenic proceeded from the process of refining; and it is found by experiment that the small proportion of antimony, arsenic, gold, silver and lead do not explain the want of ductility of the copper. The bismuth, then, only one-third of which had resisted oxydation, is the sole cause of the loss of ductility. M. Levol has proved the correctness of this conclusion by preparing different alloys. It is remarkable that bismuth which has so many points of resemblance to lead, should be so different in the above respect. It is important to examine for bismuth the coppers of commerce, in order to search out the cause of the peculiar mechanical and chemical quali ties often found, even in copper of excellent appearance.

On the bronze employed in sheathing ships.-This subject has been alluded to in the November number of this Journal. Some new facts have been brought out by M. Bobbierre, confirming the results before announced; and he has established them by experiments. For the purpose of experiment, he has made with metals either pure or impure, ingots of bronze of a cylindrical form by castings in sand, having a height of 40 centimeters and weighing 25 kilograms. Portions for analysis were taken from different parts of the ingots, both from the

surface and interior. The central parts in all cases contained less tin than the surface. For example, in the alloy of 97 of copper and 3 of tin, the richness in tin for the two parts had the ratio of 1 to 3-97. On adding to the alloy 1 p. c. of zinc, the homogeneity was much increased, the ratio becoming 1: 1·45.

Under Louis XIV, the cannon were of better quality than those of the present time; zinc was mixed with the metal, in the condition of brass. The trials made in our time have failed because the zinc was introduced directly into the alloy while in fusion, in which case the zine is burnt off and forms no combination with the fused metal.

Traité des Poisons, ou Toxicologie appliquée à la Medicine legale, à la Physiologie et à la Therapeutique, par le Docteur CH. FLANDIN. 3 vols. in 8vo. Paris, chez Mallet-Bachelier.-The first volume of this work has been some time out and has been favorably received. The author does not admit of poisons in the sense ordinarily understood. Poisonous substances are not, as has been said, irritants, etc., but substances not capable of being assimilated, which penetrate into the organism by absorption and become an obstacle to chemical or physiological action on which life depends. Thus the pathological and therapeutic department of poisoning are distinct. These views characterize the work. All the processes for detecting poisons before and after inhumation are given with details, among which are some that have given a just reputation to M. Flandin, their discoverer.

Traité de l'Electricité théorique et appliquée; par AUG. DE LA RIVE. 2 vols. in 8vo. Paris. Baillière.-The first volume has just appeared and it announces that the second will treat particularly of the applications of electricity. This work is beyond doubt the most complete that we have on the subject, and the name of the author, de la Rive, is sufficient to assure us that the facts have been experimented upon by himself, and that nothing is given without good authority.

Mécanique Analytique par LAGRANGE, 3d edit., revue et annotée par BERTRAND. 2 vols. Paris, chez Mallet-Bachelier.-Lagrange published the first edition of his work in 1788. In 1811, the principles and general applications, contained in the first edition, were extended and completed. Some obscure points remained, which one of our youngest geometricians, Joseph Bertrand, Examiner at the Polytechnic School, has elucidated with skill, profiting by the progress which the science had made since that period. The edition of 1811 having been exhausted, the new edition has been received with much favor by geometricians and mechanicians.

Leçons sur la Theorie mathematique de l'élasticité des corps solides, par LAME; 1 vol. 8vo, avec planches. Paris, chez Mallet-Bachelier.M. Lamé, one of the most learned geometricians of the Academy of Sciences, has succeeded in rendering the mathematical theory of elasticity as exact and as rigorous as rational mechanics. This work is addressed to engineers, physicists, geologists, and especially to practical men in these arts, who will find in it, rigorous laws on the action of elastic forces, and on the best plans for constructions.

La règle à calcul expliquée, où guide du calculateur à l'aide de la règle logarithmique à tiroir, par BENAIT. 1 vol. in 12mo, avec planches. Paris. Ches Mallet-Bachelier.-This work treats of the methods of constructing the sliding computing scale, and of its use in calculations.

SCIENTIFIC

INTELLIGENCE.

I. CHEMISTRY AND PHYSICS.

1. Artificial production of polychroism in crystallized substances.SENARMONT has communicated to the Academy of Sciences the results of experiments upon this subject which are very unexpected and important. The capital fact which the author has discovered is, in his own words, expressed as follows: "A coloring matter disseminated continuously in the interior of a crystal, between its layers of increment but absolutely foreign to its substance, chemically inert and capable of being spontaneously eliminated by successive solutions and crystallizations in pure water, may nevertheless communicate to it in the highest degree the properties of polychroism, and an energy of absorbing action comparable if not superior to that of substances naturally colored in which it shows itself in the most decided manner." As a proof of the correctness of this assertion, the author exhibited large crystals of nitrate of strontia formed in a concentrated tincture of campeachy wood rendered purple by a few drops of ammonia. In these crystals white light developed by transmission under certain incidences, a red color, and under others a blue or violet. Observed with a doubly refracting prism the crystals gave two images, the one red and the other dark violet, according to the thickness, and these images exchanged their colors, passing through identity, as the crystallized plate was made to turn in its own plane. Two similar and perfectly transparent laminæ superposed with a parallel orientation allowed a portion of the incident white light to pass with a purple color; superposed with a right angled orientation, they arrest the light like tourmalines, or at least reduce it to a violet shade so obscure that we may consider the light as extinct. Finally we may detach from these crystals perfectly pure and homogeneous plates slightly inclined to the optic axes. By placing such a plate very near the eye and using white natural light, we see alternately in the direction of each of the axes, a brilliant orange spot traversed by a hyperbolic branch. These open to the right and left of the principal section under the form of curved brushes composed of two equal parts of violet and sombre blue and dividing the field of the plate into two regions in which the purple tints regularly degenerate on both sides of their common limit. The dark tufts interrupted by the luminous spot are moreover fringed towards the point with a little yellow and blue, colors which are altogether local, and which arise manifestly from the dispersion of the optic axes corresponding to the differ. ent colors. These phenomena are characteristic of polychroism in crystals with two optic axes, and perfectly similar to those which Brewster observed in Cordierite, and Haidinger in Brazilian Andalusite. The author obtained similar results with other coloring matters and other crystals, and promises more ample details hereafter.-Comples Rendus, xxxviii, 101, Janvier, 1854.

[Note. The results obtained by Senarmont clearly demonstrate that the existence of polychroism in crystals by no means necessarily im. plies their chemical homogeneity, since this polychroism may in any SECOND SERIES, Vol. XVII, No. 51.-May, 1854.

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