ART. X. Mémoires de la Classe, &c. ; i. e. Memoirs of the Class of Mathematical and Physical Sciences, in the Institute of France, for the Years 1813, 1814, and 1815.

[Article concluded from the last Appendix.]

WE WE had some doubts whether the great extent of the labours of this Society would allow us, after the copious details in our last Appendix, to resume the volumes for the purpose of reporting the portion which we then left untouched: but the great variety of particulars which, on inspection, we found to be contained in M. Cuvier's usual analysis will not allow us to pass them over, nor to speak of them very briefly. We now, therefore, direct our attention to his

Analytical Report of the Labours of the Physical Class.

(1813.)

In referring to the Chevalier's comprehensive and summary intimations, however, we shall forbear to touch on works and discoveries which have already obtained currency, or which have undergone discussion in our own pages; and we shall thus leave more room for alluding to matters of less notoriety, but which may seem to be recommended to public attention by their claims to originality, or their promise of usefulness.

Physics and Chemistry. The experiments and observations of M. Gay Lussac on the formation of cold, by the escape of condensed air, would lead us to infer that the reduction of the solvent power of water is not attributable to the mere pressure of air, but that it is a phænomenon in some respects analogous to that of pure and perfectly tranquil water continuing uncongealed at a temperature below the freezing point, until the liquid is agitated. The attempts to communicate the magnetic virtue by the medium of the violet rays of light have failed in so many instances, that Morrichini's alleged discovery begins to be discredited: but, as it has been verified in a few other cases, without any obvious cause for the difference of the results, recourse should be had to more patient investigation. The successful attempts which had been made in the neighbourhood of Liege to procure malleable zinc, on a large scale, have been discouraged by the report of the members of the chemical and medical classes of the Academy, who have given it as their opinion that zinc is too readily dissolved by the slightest acids, by fat, and even by pure water; and that the salts which it forms are too acid, and too apt in certain cases to excite the intestines, to be used for domestic purposes with impunity.

Mineralogy and Geology. The discerning researches of MM. de Halloy, de Serres, de Férussac, and others, relative to fossil-shells, and especially to their distinction into marine and terrestrial, are of considerable importance; as far as they tend to confirm the doctrine of alternate depositions of salt and fresh water, which had been previously embraced by MM. Cuvier and Brongniart in their masterly delineation of the Parisian basin. The study of this distinction, however, is not unaccompanied by difficulties; for species only can be received as a test of difference, most of the genera including species of both descriptions; nay, even varieties require to be sedulously noted, because the same species sometimes undergoes such alterations as to deceive the observer who has not marked all its transitions of form; and the perplexity is increased when shells, in their fossil state, are deprived of their epidermis and other evanescent characters. Besides, there are species which, indifferently, inhabit either fresh or salt water, and which most frequently occur about the æstuaries of rivers. M. Marcel de Serres has bestowed much pains and diligence in his endeavours to reduce this novel department of inquiry to systematic principles. Two young and able naturalists, MM. Desmarest and Léman, have recognized, in the fresh-water soils of our environs, even such minute bodies as the shells of those entomostraca called Cypris, and the seeds of a genus of plants denominated Chara. Prior to their investigations, these seeds were supposed to be shells, and were known by the name of Gyrogonites.-M. Brongniart's new arrangement of rocks is announced in very general terms, but will, we trust, soon be fully developed in his system of geology. His discovery of secondary or transition syenite, in the department of the Channel, coincides with Von Buch's observations in Norway, and strengthens the inference that precipitations of crystallized rocks still took place after the manifestation of life in the waters which antiently encompassed the globe.

Vegetable Physiology and Botany.-M. Desvaux has ascertained that the closing of the flowers of the mesembryanthemum originates in the calyx, and not in the corolla; and that, if the former be removed, the latter remains expanded. M. de Mirbel impugns the accuracy of Malpighi's alleged analogies between the tunics which invest the foetus of an animal in the womb, and those which inclose the seed of plants. His speculations on the regulated form of the pericarp, although abundantly ingenious, will rarely suffice as a basis of classification: but more serviceable discriminations may be derived from his remarks on the internal structure of the seeds. Some

valuable

valuable characters and useful divisions may also be deduced from the observations of the younger Cassini, who has directed his attention to the structure of composite and syngenesious flowers, and has discovered some particulars which had eluded the scrutiny of preceding botanists: for example, the articulation of the filament near the anther, which he finds to be much more constant than the union of the anthers with one another. MM. Desvaux and de Beauvois have entered into a formal discussion concerning the nature of the yellow and combustible powder obtained from the Lycopodia; the former regarding it as composed of propagula, as he terms them; and the latter, as a genuine pollen. M. Decandolle has thrown considerable light on a race of parasitical fungi, which infest the roots of various plants, particularly those of the saffron and lucerne. Their presence in the lucerne fields is indicated by circular spaces of the discoloured crop; and the most effectual mode of preventing the farther propagation of the mischief is to cut sufficiently deep trenches round the infected spots, and thus arrest the extension of the root-like fibres.

Zoology, Animal Physiology, and Anatomy.-M. Cuvier lays before the Academy some curious notices of certain species of fish, which had either been overlooked by modern ichthyologists or unduly multiplied as species. In this track he is followed by M. Noel de la Morinière, who has consecrated many years of his life to the history of marketable fishes. M. de la Billardière announces that he found, in the nest of the Apis Sylvarum of Kirby, an old female and a working bee, whose wings were so pasted by a brown and compact wax as to render them incapable of flight; and he presumes that this was a precaution adopted by the other humble bees, to constrain these two individuals to remain in the nest, and nurse the larvæ of the future progeny. In consequence of an elaborate examination of the dorsal vessel of insects to which some entomologists had attributed the functions of a heart, M. de Serres is induced to believe that its appropriate office is the production of fatty matter. Dr. Montègre, of Paris, who has instituted a series of experiments on the common earthworm, conceives that it is not affected by light, or sound; and he has ascertained that it does not subsist on the juices derived from earth alone, having found in its viscera the relics both of plants and animals. M. Magendie's experiments on the action of vomiting are stated at some length: but they are too cruel to be detailed; and we advert to them here merely for the purpose of remarking that they lead to the somewhat unexpected conclusion, that the nausea and other symptoms

symptoms are occasioned by the compression of the muscles of the oesophagus and diaphragm on the stomach, and not by any immediate irritation of the coats of the last mentioned viscus. The same gentleman has satisfactorily proved that the tartrite of antimony, in a large dose, is of itself a mortal poison, but that, most of it being speedily rejected by vomiting, it often fails to prove fatal. He also submits a series of observations relative to the use of the epiglottis ; which would appear to be destined to some other purpose than that of preventing the substances swallowed from entering into the wind-pipe, since both men and quadrupeds, when deprived of this cartilage, swallow with perfect safety, the glottis naturally closing at the moment of deglutition.

Agriculture, and the Veterinary Art. — M. Marsan, professor at Padua, communicates a memoir on the Holcus Cafer; which, though indigenous to Africa, has been successfully cultivated in Italy, Bavaria, and Hungary, and which promises to yield more sugar than any of the substitutes that have been hitherto proposed for the cane. Dr. Levrat recommends the seeds of the common flag (Iris pseudacorus) as the best succedaneum for coffee: for which purpose, they should' be dried at the fire, stripped of their friable envelope, and roasted and ground like that berry. Their infusion is said to possess the same febrifuge properties as that of the latter, and may be exhibited instead of bark. As the antient rural economists expatiate on the advantages of cloathing sheep, Dr. Chambon took the pains to put the practice to the test: but he found that the consequent melioration of the wool afforded no adequate return for the expence of their wardrobe, so that the owners of flocks would soon discover them to be wolves in sheep's cloathing.

Medicine and Surgery.-M. Pictet, of Geneva, apprizes the Academy of the cure of a man whose breast had been completely pierced by the shaft of a cabriolet; and of the successful treatment of a distinct case of hydrophobia, in India, by excessive bleedings, which were repeated on every appearance of relapse.

1814. (Misprinted 1815.)

Chemistry.-From the examination to which M. Pelletier has subjected the colouring matter extracted from sandal-wood, and from onosma, and which were heretofore regarded as simple resins, it appears that the first unites to the properties of most of the resins those of being soluble in the acetic acid, even when much weakened; of yielding oxalic acid by means of the nitric acid; and of exhibiting some other characters,

found the only effectual preservative against the contagion ; and, although the affected individuals never recovered, their flesh was eaten without inconvenience. The same academician gives some account of a disorder which had prevailed among the cattle of the village of Rosny, and which was at first suspected to be hydrophobia, but proved to be a gangrenous quinsey.-M. Tollard recites the history of such vegetables as have been introduced into the system of French culture, in the course of the ten preceding years; besides composing a memoir on the genus Dahlia, a plant which now so generally figures as an ornament in our gardens, and of which the large roots are edible and nutritious.

1815.

Chemistry. Great as is the influence of light on most of the phænomena of nature, the range of observation and experiment on the subject is comparatively limited. A few facts, which M. Vogel has added to our former slender stock of information, deserve to be stated. Ammonia and phosphorus, which evince no mutual action in the dark, disengage phosphorated hydrogen gas in the solar rays, and deposit a black powder, composed of phosphorus and ammonia, in a state of intimate combination. The action of the different rays is not always similar: thus, the red produce no effect on a solution of corrosive sublimate in ether; whereas the blue and complete light effect a mutual decomposition. The highly oxidated metallic muriates are reduced, by the same means, to the minimum of oxidation.

Mineralogy and Geology. By combining the mechanical subdivision of certain portions of basalt, &c. with their chemical analysis, M. Cordier flatters himself that he has made an important step in distinguishing between antient lavas and rocks merely reputed to be such: - but, in speculations of this description, one historical fact is worth many operations in our laboratories, however sagely conducted. On this topic, we may also notice the Journal of M. Mesnard de la Groye, a young and zealous naturalist of Angers; who, during the years 1812 and 1813, watched the phænomena of Vesuvius with an assiduity and discernment which have been rarely surpassed. The following passage contains the substance of some of the most important of his statements:

He likewise draws our attention to the volumes of vapour which incessantly ascend from the currents of lava, and which announce their great humidity; for they are, in fact, merely aqueous. We see no real flames: but the ignited sand and stones, and the reverberation of the internal focus on the vapours which issue from it, produce the illusory semblance of them. The lava advances