Many persons contested the prize. The desideratum is to obtain a coating of carbon in a manner analogous to that from silver or gold, namely, by reduction. But chemistry as yet has failed to discover a process for the reduction of carbon compounds, and photographers have resorted to animal black which they have applied in any convenient manner to plates previously exposed to the sun. We give a résumé of the new results in two memoirs esteemed by the Commission worthy of reward. Messrs. Garnier and Salmon, the authors of one of these memoirs, cover the surface of paper with a film obtained from an intimate mixture of bichromate of ammonia and albumen. This coating is dried by heat and exposed to the sun in a frame covered by a glass positive. The picture appears in a yellow-brown tint which becomes more intense by a gentle warmth. The sheet thus prepared is fixed on a planchette and covered with finely powdered ivory-black, the coating being made even by a stump of cotton. It is next detached and plunged in common water, the image uppermost, and there gently moved at intervals for a quarter of an hour. The water is then drawn off and the picture served in a bath composed of 5 parts of concentrated sulphurous acid diluted in 100 parts of water, moving it about as before at intervals. After this double pro cess the carbon almost entirely disappears from the lights and clear spaces, while it remains in quantities proportional to the greater or less intensity of action of the light upon the other portions, and thus the proof finally reproduces the positive, but not perfectly, since the lights and half tints are not pure and the blacks lack somewhat of brilliancy and perfectness. But the process is simple and good; it remains only to perfect it. M. Pouncy, another competitor, operates a little differently, but obtains results equally satisfactory. His process differs in applying the carbon before exposure of the proof to light, the sensitive coating being formed at once, of bichromate of potassa, gum arabic and finely divided carbon, exposed not under a positive but under a negative plate. On removal the plate is placed in a bath of pure water; after five or six hours immersion he washes under a cock of common water and the carbon positive is obtained. In this process the manipulation is a little easier and more simple. The use of a negative authorized the expectation of a better result, but the exposure is longer than in the mode of Garnier and Salmon, whose use of a positive avoids the chances of accident which attend the negative plates in the hands of the operator. Messrs. Pouncy, Garnier and Salmon share the prize with Mr. Poiterin, who has the merit of anticipating these photographers, whose methods are only an advance on the process which Mr. Poiterin published in 1856. Transformation of cellulose into sugar.-We have already spoken in this Journal of the plan of Pelouze for facilitating the experiment of Braconnot-the transformation of cellulose into sugar-by exposing the woody fibre and dilute acid to high pressure and heat. It is known, and the fact is recognized by M. Pelouze himself, that this idea has been some years since put in practice both by Mr. Weil and also by Mr. Tribouillet, who obtained a patent for the process. This volume, page 126. Transformation of cellulose into parchment or parchment-paper.-It appears that this curious product of the action of concentrated sulphuric acid on bibulous paper, by which means the paper is changed to a tissue very much resembling ordinary parchment, nearly as strong and resisting the action of boiling water, which parchment does not. It appears that this is not a new observation, but was first made known in 1846 by Messrs. Poumarêde and Figuier in the Journal de Chemie et de Pharm. for 1847, under the name of papyrine. This product however was prepared by aid of an acid of less concentration than is used for parchmentpaper and consequently it did not possess all the desirable properties belonging to vegetable parchment, which is susceptible of a multitude of important applications. Acclimation. The Dromedary imported into South America. On the 21st of June last the ship "Splendide" of Marseilles sailed from the port of Algiers for Brazil, having on board fourteen camels (four males and ten females) selected and purchased by the Society for Zoological Acclimation (Societé Zoologique d'Acclimation) to the order of the Brazilian government; this government having decided to test the acclimation of these animals in the sandy provinces of Brazil. Several of these provinces, particularly Céara, during many months of the year are destitute of water, and much resemble in physical characters those regions of Africa and Asia where the camel and dromedary are so eminently serviceable. The Society of Acclimation, in view of the importance of the case, have sent one of the Vice Presidents of the society, M. Richard (du Cantal), a distinguished zootechnist, to Algeria, between Boghar and Lagonat, in a region inhabited by one of the tribes most distinguished for the number and beauty of their dromedaries. From these herds Richard selected ten females of three to four years old, three males of four years, and one of seven, all in the highest condition, at a cost of 380 francs each. Four Arab camel drivers were also obtained to accompany the animals. The July (1859) number of the Journal of Acclimation relates all the history of this experiment, to which we refer for the details. But it is to be remarked as regards the prospect of success for this enterprize that a similar experiment has met with success some time since in Texas and Central America, the credit of which is due to Major Wayne of the United States Army. BIBLIOGRAPHY.-There has appeared from the central book depot of Agriculture at Paris Dictionnaire raisonné d'Agriculture et d'Economie du Bétail par le Dr. Richard, du Cantal, 2 vol. in 8vo.-Richard is one of the Vice Presidents of the Society for acclimation spoken of above. He is best known for his intimate knowledge concerning domestic animals and especially of what in France is called Zootechny. The two volumes of his Dictionary are filled with his observations on this important agricultural question. MALLET-BACHELIER, quai des Augustines, Paris, has publishedRecherches sur les Météores et sur les lois qui les régissent par Coulvier Gravier. 1 vol. in 8vo, with numerous plates.-Mr. Coulvier Gravier has brought out in this volume the fruit of forty years of observations on the state of the heavens. We have often found occasion to mention his ob servations on shooting stars. This work embraces all belonging to what are called meteors. The author is under great obligations to the French government who, on the recommendation of Arago, placed Mr. Coulvier Gravier in a situation to follow his tastes for this sort of observation. This observer does not despair of obtaining the means of predicting the meteoric periods. He unfolds his theory in a volume which all can understand, since it is written in a simple style and contains few mathematical formulæ. It shows that the author has obeyed a controlling taste; and his work fills an important gap in astronomical bibliography. Cours de Mecanique appliqueé par M. Mahistre. 1 vol. 8vo, illustré de 211 figures. Mr. Mahistre is professor of Mechanics a la Facultè des Sciences a Lille, one of the great manufacturing centers of Europe. His admirable work is especially adapted to engineers and to students who are destined to industrial pursuits. Cours de Mécanique appliquée par M. Bresse. T. 1.-Mr. Bresse is Professor of Mechanics at the celebrated Ecole des Ponts et Chaussées. This first volume treats specially of the strength of materials. Like the work of Mahistre, it is particularly adapted to civil engineers; above all it interests the engineers of bridges and roads, who in France occupy so important a rôle, particularly in railroad constructions. Multitudes of these engineers are found scattered over the continent of Europe, especially in Russia, Germany, Spain, Switzerland and Belgium. The science of the pupil gives evidence of the master, who is Mr. Bresse. Cours d'Electrophysiologie par M. Matteucci. 1 vol. 8vo.-This course pronounced at the University of Pisa is now reproduced in France where the well known high reputation of the author will secure it the attention it deserves. Cours d'Analyse de l'Ecole Polytechnique par M. Sturm. T. II, in 8vo, 1859. We have already announced the first volume of this great mathematician, who died some years ago. It is published by one of his pupils, Mr. Proutret, by the choice of the author, and from the manuscript left by him. This work is of special value to professional mathematicians, and to those who are charged with the instruction of this science. SCIENTIFIC INTELLIGENCE. I. CHEMISTRY AND PHYSICS. 1. On Torsion and its relations to Magnetism.-WIEDEMANN has communicated several interesting papers on torsion and its relations to magnetism, from the last of which we extract the following comparative view, referring to the original paper for the details of the experimental methods employed. Torsion. 1. The temporary torsions of a wire twisted for the first time by increasing weights, augment more rapidly than the weights. Magnetism. 1. The temporary magnetisms of a bar magnetized for the first time by increasing galvanic currents, augment more rapidly than the intensities of these currents. 2. The permanent torsions of the wire increase still more rapidly. 3. A much smaller force is necessary to untwist the wire than to twist it. 4. By repeated turnings of the wire, its torsions approximate more and more closely to a proportionality with the turning weights. The torsions are thereby greater than in the first turning. 5. By repeated application of the same twisting and untwisting weights, G. and G. the maximum of torsion reached in the turning, sinks, and the minimum reached in the detorsion of the same, rises up to a definite limit. 6. When twisted beyond the limits of the repeated torsions and detorsions the wire behaves as if it were twisted for the first time. 7. A twisted wire which is untwisted by the force -G cannot be twisted by repeated action of the force G in a direction opposite to the first torsion. But the force +G twists it easily in the first direction. 8. When a wire which possesses the permanent twisting A is brought by the force b to the torsion B and then farther to the torsion C, which lies between A and B we need the force b to give it again the torsion B. In this case, A may be also 0, and B may be greater or smaller than A. 9. Vibrations during the action of a twisting weight increase the torsion of a wire. 10. The permanent torsion of the wire after removing the twisting weight, is on the contrary, diminished by vibrations. 2. The permanent magnetisms of the rod increase still more rapidly. 3. A much weaker counter current is necessary to demagnetize the bar, than to magnetize it. 4. In a case of repeated magnetizations of the bar, its magnetisms approach more and more closely to a proportionality with the intensity of the magnetizing currents. The magnetisms are thereby greater than in the first magnetization. 5. By repeated application of the same magnetizing and demagnetizing currents, J. and J. the maximum of magnetism reached in the magnetization, sinks, and the minimum of the same reached in the demagnetization rises up to a certain limit. 6. When magnetized beyond the limits of the repeated magnetizations and demagnetizations, the bar behaves as if it were magnetized for the first time. 7. A magnetized bar which is demagnetized by a current of the intensity J cannot be magnetized in a direction contrary to that of the first magnetization by repeated action of the current -J. But the current +J magnetizes it easily in the first direction. 8. When a bar which has the permanent magnetism A is brought by the current b to the magnetism B, and then farther to the magnetism C, which lies between A and B, we need the current b a second time in order to communicate again the magnetism B. In this case A may also be 0, and B may be greater or smaller than A. 9. Vibrations during the action of a magnetizing current, increase the magnetism of a bar. 10. The permanent magnetism of the bar after removing the magnetizing current is on the contrary, diminished by vibrations. SECOND SERIES, VOL. XXVIII, No. 84.-NOV., 1859. 11. A wire twisted and then untwisted loses or gains torsion by vibration according to the magnitude of the detorsion. 12. The permanent torsion of iron wires diminishes by their magnetization, and that in a ratio which diminishes as the magnetism in creases. 13. Repeated magnetizations in the same direction scarcely diminish the torsion of the wire. A magnetization in the opposite direction to the first produces however a new strong diminution of the torsion. 14. When a wire, by frequent magnetizations in opposite directions, is untwisted as far as possible by this process, it assumes by magnetization in one direction a maximum, by magnetization in the opposite direction a minimum of torsion. 15. A twisted wire which has been partially untwisted, loses by magnetization much less of its twist than an ordinary twisted wire. A wire farther untwisted, exhibits on feeble magnetization at first an increase of its torsion, which by augmenting the magnetization rises to a maximum and then again diminishes. The more strongly the wire was untwisted, the stronger must the magnetism be, in order to reach this maximum. When the wire is very strongly untwisted, its torsion increases, even up to the application of the strongest magnetization. 16. When a wire is magnetized while under the influence of the twisting weight, its torsion increases by weaker, diminishes by stronger magnetization. 17. A wire twisted at the ordinary temperature loses torsion by heating, and on cooling again recovers a portion of its loss. The changes increase with increasing torsion. After repeated changes of 11. A magnetised and then demagnetized bar loses or gains magnetism by vibration, according to the magnitude of the demagnetization. 12. The permanent magnetism of steel bars diminishes by their torsion and that in a ratio which diminishes as the torsion increases. 13. Repeated torsions in the same direction diminish the magnetism of a steel bar but little. A torsion in a direction opposite to the first, produces, however, a new strong diminution of the magnetism. 14. When a bar by repeated twisting and untwisting is demagnetized as far as this is possible by torsion within definite limits, it assumes a maximum of magnetism by torsion in one, and minimum by torsion in the opposite direction. 15. A magnetized bar which has been partially demagnetized, loses by torsion much less magnetism than an ordinary magnetized bar. A bar, which has been farther demagnetized, exhibits on feeble torsion, at first, an increase of magnetism which on increasing the torsion, rises to a maximum and then again diminishes. The more strongly the bar was demagnetized, the stronger must be the torsion to reach this maximum. When the bar is very strongly demagnetized the magnetization increases even up to the application of very strong torsions. 16. When a steel bar is twisted when under the influence of a magnetizing current, its magnetism increases by weaker, diminishes by stronger torsion. 17. A bar magnetized at the ordinary temperature, loses magnetism by heating, and on cooling recovers a portion of its loss. The changes are proportional to the magnetization. After repeated changes of |