In place of a sudden diminution in the quantity of rain like that on this side the Rocky mountains of America, there is only a gradual change in the old Continent, where the steep ranges do not come quite down to the west coast. To the rain-torrents which pour down along the foot of the Sierra d'Estrella and made the siege of Coimbra under Don Miguel so tedious, there had been a parallel only in Norway where the mountains run down so sharp to the westward that the sea fills the transverse valleys, making them fiords, until lately the occurrence of that unheard of fall of rain which swept down in the neighborhood of the Cumberland Lakes and excited such universal wonderment in England. They knew of course, that, as the captains in the North Sea ask one another if it rains in the mountains, so a traveller on the west coast of England enquired impatiently "if it always rained there," and got the quieting answer, "no, it sometimes snows;"-but no one supposed that in Langdall there fell 123 inches of rain, in Gatesgarth 136, in Scathwaite 142. In Ireland, this diminution of the quantity of rain on the west coast comes more gradually; but here too, there is, as Lloyd has shown, a peculiarity depending on the position of the mountains with reference to the point where the observations are made: a range of mountains to the northeast having great influence, but little if to the southwest. Hence it is that we find in Cahirciveen 594, and in Portarlington only 21"; for the former lies, like West Point with 459, and Castletownsend with 42"-5, on the SW side of high mountains, on the other side of which are Portarlington on the Slievebloom, just as Kellough with 23"-2 on the NE of the Mourne Mts., although all these stations are right on the edge of the sea. This diminution is seen clearly in Prussia; for the 30" of Cleve become 25" in Cologne, Bonn, Aachen (Aix la Chapelle), and Trier, 22" in Berlin, 19" in Posen. The Riesengebrige of Silesia makes a dividing wall, which gives on the south side heavy showers, on the north side generally only inconsiderable rains. Thus the insignificant quantity of 14" in Prague becomes 33" in Hohenelb, and diminishes in Neisse to 16. Still more remarkable is this fall in Russia; for the 17 English inches in Petersburg, Bohoslowsk and Slatoust, become 15 in Catharineburg and 11 in Barnaoul. Ajansk on the Sea of Ochotsk, with 35", shows that here too the increase landward is conditional, since the moving air of the continent here make east winds; for of these 35", 30 come in summer and autumn; Pekin shows the influence of the monsoons, since of its 27", 20 come in the three summer months.

The time of the maximum amount of rain as well as the small annual diminution of atmospheric pressure in the south, extends through Central Asia into Hindostan. There is just as little trace of a Subtropic zone here as in America. In Redutkale on

the southern slope of the Caucasus, there fall 58" of rain, in Kntais 50", in Tiflis only 19" for high chains of mountains lie SW of it. The significant quantity of 43" in Lenkoran, whose distribution recalls the Subtropical rains, diminishes on the other side of the chief range of the Caucasus in Baku to 13-4, in Derbent to 157, a proof that the source of that fall is not to be sought in the Caspian Sea which washes these places, but lies off to the SW. The inconsiderable amount of rain appears to show that the masses of air over Africa are unaccompanied by heavy vapors; hence from Africa to the interior of Asia in the direction of SW to NE, there lies a waste tract, in which the evaporation exceeds the fall of rain; consequently, the level of the interior waters, as in the Dead Sea, the Caspian and Aral, is below the level of the Ocean, and just in proportion as they are nearer to the Equator; while on the southern slope of the Andes and Appenines the Sirocco betrays, through powerful rains, its cradle, which lies, as I have long since demonstrated, not in Africa, but in the Sea of the West Indies.

Why in England the autumn rains are so much more important than the summer rains, a subject which has attracted Dalton's attention, will not be fully ascertained until for many years, such registering instruments as those of Osler at the Liverpool Obsevatory, have been in general use for ascertaining all the phenomena accompanying each shower, and especially the direction and intensity of the wind.

The distribution of rain in annual periods is very different in different neighborhoods; it may become the same however, after a time in different localities, and from very different causes.

Un

less attention be paid to all these causes the graphic exhibition of the results may make the explanation more difficult, instead of simplifying or elucidating the subject. [We omit the tables, which follow, referring to the original paper in Poggendorff's Annalen, for January, 1855, vol. xciv, p. 58.]

ART. XVII-Correspondence of M. Jerome Nicklès, dated Paris, Oct. 30, 1855.

Death of M. Magendie.—At the opening of one of the recent ses sions of the Academy of Sciences, the President announced the death of Dr. Magendie, after a long and painful sickness. In another communication I propose to give a biographical sketch of this savant, whose labors have done so much for the progress of experimental physiology.

M. Bruconnot.-The decease of M. Braconnot was noticed in the May number of this Journal, and I now add a brief memoir of this chemist, as then promised.

HENRY BRACONNOT was born on the 29th of May, 1780, at Commercy, Department of the Meuse. His father, a lawyer, died seven years after, leaving two sons, of whom Henry was the older. His property was not large, but was still sufficient to give his two children, who were bright and active, a good education. At that time, the education of children was wholly in the hands of the clergy who recognised no punishment excepting corporeal inflictions. Braconnot was placed in a college of Benedictines, and brought little honor to his teachers. The slightest misdemeanor was met with a blow of the ferule-a mode of correction calculated to exasperate rather than improve, and espe cially injurious to this rather impetuous child. He grew more and more ungovernable, and finally stood in open revolt against his reverend op. pressors; uniting with one of his companions equally spirited, and having like him a feeling of a man, he became the terror of his gov. ernors. His mother in despair, took him from the Benedictine college and entrusted him to a village schoolmaster noted for his severity; but the pedagogue succeeded no better than the Benedictines; he sent young Henry home, presaging for him a dark future.

Meeting with the Benedictines, at this time, they expressed the same opinion of his comrade. But they were mistaken in both. We know what Braconnot was; his companion in frolic became afterwards Dr. Marjolin, formerly Professor at the Faculty of Medicine at Paris, and one of the first physicians of the modern school.

Young Braconnot now engaged earnestly in chemical studies. He spent four years at Strasburg. He then returned to Paris to perfect his education, where he attended the courses of Fourcroy, Geoffroy St. Hilaire, Desfontaines in Botany, and Faujas de St. Fond in Geology. He was noted for his zeal, carried off prizes, and published his first work entitled "Analysis of a fossil horn found in an ancient cave.” This memoir was soon followed by another "on the assimilating force in plants," which was published in the Annales de Chimie et de Physique. It attracted the attention of Fourcroy, then of great influence, who secured for him the directorship of the Botanical Garden of Nancy (1807). The death of his father-in-law now left to his mother a large fortune which ultimately came to Braconnot; his mother living until her death at Nancy.

From this time his memoirs succeeded one another without interruption. In his analyses, he discovered successively pectine, populine, equisetic acid, ellagic acid, and pyrogallic acid. In 1820 he suddenly changed his line of investigation, and took up the products of the decomposition of ligneous fibre by acids, discovering xyloidine, leucine, sugar of gelatine, and the transformation of wood into sugar-this last a work of the very highest merit.

Braconnot in mature years was the reverse of what he was in youth; modest and mild even to extraordinary timidity, he was understood by only a few friends. His townsmen thought him of contracted mind, and one day were surprised to learn that he was a Member of the InstiBut alongside of his timidity, there were decided opinions. Profoundly sceptical, he believed nothing and doubted especially medicine. Always at war with the doctors, he would have none of their advice when ill. He thought that nature could do everything, and he died

tute.

with great suffering from a cancer in the stomach, unwilling to the last to take council from the doctors or his friends.

Bayle, Diderot, Voltaire, were his favorite authors. His tastes and habits were of extreme simplicity; he lived on little and had no diver. sion but the theatre and the promenade. He saw his mother unfortu nately married, and he suffered much from his father-in-law who was a physician; and this may have occasioned his celibacy, and his hatred of medicine.

Like Scheele, he made his researches with very restricted means. He had one good thing in his laboratory-his reagents, which he prepared himself, of extreme purity. But he was unwilling to admit any one into his laboratory. Arago on a visit to him asked the favor in vain. He was often at Paris, and took part in the sessions of the Institute, but not at their banquets open to the public. His timidity even hindered him from visiting chemists, being contented with seeing them at a distance.

Heat produced through the action of the magnet on bodies in motion. -The gyroscope of Foucault, described in a former volume of this Journal, is far from having said its last word. The author has just established by means of it, the recent views as to the relation between mechanical force and heat. M. Babinet announced the results to the Academy on the 17th of September last with a vivacity and enthusiasm quite indescribable, and which was shared by his auditors.

Foucault placed between the poles of a strong electro-magnet the solid of revolution belonging to the gyroscope. This solid is a torus of bronze connected with a toothed pinion of a motive wheel, which has a handle and is made by the hand to make 150 to 200 turns per second. To render the action of the magnet more effective, two pieces of soft iron are added to the bobbins, prolonging the magnetic poles and thus concentrating them close to the revolving body.

When the apparatus is moving at its greatest velocity, a current from six Bunsen's couples passed through the electro-magnet stops the motion in some seconds, as if an invisible rein had been thrown around it. This is the experiment of Arago developed by Faraday. But if now force is applied to the handle in order to restore the motion, the resistance compels the use of a certain amount of power, which is represented in heat in the interior of the turning body. By means of a thermometer, the progressive elevation of temperature was noted. Taking the apparatus, for example, at the surrounding temperature 16° C., Foucault found the mercury rise to 20°, 25°, 30°, 40°, when heat was quite sensible to the hand.

Foucault thinks he may easily construct an instrument which will exhibit on a large scale this phenomenon. By means of a machine easily made consisting only of permanent magnets, we may produce an elevated temperature and exhibit to a public assembly this curious example of the conversion of labor into heat.

On the neutral combinations of saccharine substances with the acids. -At the same session of the Academy, a research by M. Berthelot excited equal attention. We have spoken of Berthelot's reproducing synthetically the existing fatty bodies; he now prepares a multitude of new bodies by combining with acids certain organic substances analo

gous to glycerine, such as mannile; Dulcose C12H14012, a peculiar sugar found by Laurent in a Madagascar product; Quercite Ċ12H12 Q10, discovered by Braconnot in acorns, though confounded by him with lactine and afterwards proved to be a distinct principle by Dessaignes; Pinite, C12H12010; Erythroglucine, C12H15012, cane sugar and glucose.

When these different substances are put into a closed tube containing the acid with which it is proposed to combine them, and sufficient heat is applied, the combination usually takes place; and on opening the tube, after cooling, it is only necessary to remove by appropriate solvents the new substance from the material about it. Thus mannite, quercite, and the other substances mentioned have been obtained com. bined with acetic, butyric, stearic, oleic, palmitic, benzoic acids.

Chevreul in presenting this memoir, which he did with animation, equal to that of M. Babinet for the memoir of Foucault, said: "Thirty years since I foresaw that most of the neutral fatty bodies could result from a combination of glycerine with a fatty acid. To demonstrate this law, rigorous quantitative analyses were necessary, which I then thought impossible. Since then Science has moved on, and the proba ble has become the ascertained composition. But Berthelot has gone further. By the reaction of pure acids on glycerine also pure, he has succeeded in fortning with precision many neutral fatty bodies-not only those before known, but others which had not been isolated. Glycerine, as is well known, has a sweet taste; and it was hence natural to enquire whether the other saccharine substances could be united, by synthesis, to those same acids. This is the object of Berthelot's recent investigations, which have been so eminently successful.

Observations on Cholera.-The subject of the cholera still continues to occupy the Academy. The developments as to its causes and cure have not yet been deemed sufficient to call for the 100,000 francs offered by the chemist Bréant : still some interesting results have come out, the influence of climatal conditions favoring or combating the disease have been shown in statistical researches. The statement is also noted that from the time of a great fire at Varna, the cholera, which had been very fatal, began immediately to diminish and the sick were in rapid convalescence. Dr. Burg has deduced from his researches that persons working in copper and brass escape this pestilence, even when living in infected districts. In 1832, when the cholera was prevailing at Paris, the tanners and leather-dressers escaped it almost entirely, although occupying the worst parts of the city. Dr. Hubertz, a Danish physician, has made similar observations at Copenhagen.

He says, "persons employed in emptying privies, even those used by cholera patients, were not attacked by cholera. The same was true of men employed in drying fish, in making cat-gut, and other employ. ments regarded as unhealthy because of the putrid emanations attending the work. Even those employed carrying the dead and digging graves were completely spared.

New process of manufacturing soda and sulphuric acid.—In place of a dull and imperfect review of the "Universal Exposition," it seems better to describe a new process, yet unpublished, which promises to change one of the most important industries of the age.