this second kind into the French colonies, as a tree from which singular advantages may be derived. Two engravings are subjoined.

Observations on Terrestrial Refraction. By M. DANGOS, Associate of the Institute.-The phænomenon here described was observed at Malta, March 20, 1784, about one o'clock. An island seemed to rise out of the sea in the canal of Malta; a peculiar appearance, which M. DANGOS observed more than once, and which was caused by the reflection of the snowy top of Mount Etna: but this image, it is contended, could not have been effected by one simple reflection on the surface of the sea. It is remarked that a thick fog preceded this phæno

menon.

Memoir on the Pepper conveyed in 1788 from the Isle of France to Cayenne, by M. MARTIN, by order of the Minister La Luzerne, and on the Advantages of its Culture in that Colony. By J. B. LEBLOND. Of all the spices, pepper is in the most general use, and its cultivation is of the most importance. On this subject, the author of the present memoir quotes the observations of M. Velloso, a Portuguese writer, and of M. Huffenet, au experienced agriculturist in French Guiana.

An Attempt to form a new Natural Classification of Reptiles. By ALEX. BRONGNIART, Professor of Natural History, &c.—The substance of this ingenious essay is contained in two sections, the first of which relates to the rules that should be followed in this classification, and the formation of orders; and the second, to the formation and disposition of the genera. After having adverted to the difficulties which attend the undertaking, and to the objections with which the former methods of arrangement are embarrassed, M. BRONGNIART proceeds to develope his new classification; which contains four orders of reptiles, nicely characterized by their organization and external parts. Order I. consists of the Chéloniens, or reptiles analogous to the tortoise, whose distinctive external characters are, that they have no set-in-teeth, and that the body is covered with a sheil. Order II. of the Sauriens, or reptiles resembling the lizard; the external characters of which are, that they have claws, teeth set-in, and the body covered with scales. Order III. of the Ophidiens, or reptiles resembling the serpent; the external characters of which are, that they have no claws nor feet, and have long cylindric bodies. Order IV. of the Batraciens, or reptiles analogous to the frog, having feet and a naked skin. The several genera which occur under each of these divisions are specified in the second section: but it will not be expected

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expected of us to enter into this detail. The curious naturalist will, in course, peruse the whole of the essay.

We have now taken a brief view of the contents of this large volume: which, it will be seen, are of a miscellaneous nature, and afford various degrees of merit. Our attention is next called to a continuation of our report of the regular volumes of

this learned body, according to the last livraison which has from p.460.

reached us.

Mo-y.

See pp. 457.460.

ART. II. Mémoires de l'Institut, &c.; i. e. Memoirs of the National
Institute. Vol. VI. Mathematical and Physical Sciences.

[Article concluded from our last Appendix.]

MEDICINE, CHEMISTRY, NATURAL HISTORY, &c.

MBM

BMOIR on the Bones of the Female Pelvis. By M. TENON. In this paper, which appears to us rather tedious and uninteresting, the author discusses at considerable length the question respecting the opening of the symphisis pubis during delivery; after which he gives us the result of his examination into the structure of the part, and the nature of the connection which exists between the two bones. Respecting the first object of inquiry, he adduces many powerful authorities in support of each of the opinions: but we do not perceive that any new light is thrown on the question, or that the controversy is brought more nearly to a conclusion. M. TENON seems to have examined with much minuteness the manner in which the bones are connected together; and the result of his inquiry is, that they are sometimes united by a common cartilage, while in other cases each of the bones is furnished with its separate cartilage, which are joined together by a common ligament.

--

Memoir on the Determination of three Natural Epochas for the Production of Volcanoes, and of the use which may be made of these Epochas in the study of Volcanoes. By M. DESMAREST. To the effects produced by volcanic eruptions, geologists have always had recourse, in the speculations and hypotheses which form so large a portion of their labours. As M. DESMAREST is known to have devoted himself particularly to this object, we are happy to meet with any thing from his pen, which will tend to generalize the scattered observations that occur in the writings of so many travellers and naturalists. He thinks that yo lcanoes may be arranged under three divisions, correspondAPP. REV. VOL. LII.

Hh

ing

1

ing to the length of time that has elapsed since their forma tion; and to each of these species he assigns determinate characters. Fir, those of the most recent formation possess open craters, and are surrounded with scoria, and different bodies which exhibit the immediate effects of fasion. In the secorid kind, the craters and scoria are no longer to be found, but the currents of lava may be traced, covering the horizontal strata of the earth, and intersected by streams and vallies. In the last and most antient species of volcanoes, the lava is difcovered below the horizontal strata, and not unfrequently even beneath the waters of the ocean. How far this hypothesis will be found to accord with the phænomena of nature must be determined by those who have more opportunities than we possess, of diving into the depths of geological science: but it wears a plausible appearance, and, if established, would obviously lead to some important conclusions, and tend to correct many erroneous speculations.-We are concerned to ob. serve an author of acknowleged merit, like M. DESMAREST, speak in an arrogant and supercilious manner of certain Scotch and Genevese philosophers,' who happen to differ from him respecting the formation of basalt.

Memoir on the Comparative Nature of the Gaseous Oxid of Azote, or the Nitrous Oxid of Mr. Davy, and of Nitrous Gas. Ey MM. FOURCROY, VAUQUELIN, and THENARD.-After some observations on the history of the nitrous oxid, in which is justly ascribed to Dr. Priestley the discovery of most of its properties, except its action on the animal economy, the authors give an account of the experiments which they instituted for the purpose of analyzing the two gases. They performed the decomposition by transmitting them over iron filings, in hot earthen tubes. We have then a relation of the effects produced on M. VAUQUELIN, by the respiration of the nitrous oxid; which seems to have partaken more of the nature of asphyxia, than of that increased action which was experienced by Mr. Davy and his friends. On the whole, we do not think that this paper is worthy of the talents of the three chemists whose names appear in the title.

New Experiments on Cow's Milk, by MM. FOURCROY and VAUQUELIN. We are here presented with some important additions to the knowlege which we previously possessed, respecting the composition of this fluid. It has been already announced that the acid which is developed during the coagulation of milk, and which was supposed by Scheele to be endured with specific properties, is merely the acetic acid, united to a portion of animal matter; and in the paper before us, the authors

give in detail the experiments on which the opinion is founded. They also state that milk, when fresh drawn, contains a -small quantity of acetic acid: that the phosphate of magnesia, as well as that of lime, has been detected in this fluid; and that it likewise contains a small quantity of iron, probably also in the state of a phosphate. The animal matter which is united to the acetic acid, they suppose to be similar to the gluten in wheat.

Memoir on Guand, or the Natural Manure of the Islands of the South Sea, near the Coast of Peru. By the Same.-M. Humboldt, during his travels in South America, observed a singular substance on some of the small islands near the coast of Peru, which is employed for the purpose of manure in the neighbouring parts of the continent, and seems to possess the requisite properties in a very high degree. It forms a stratum of considerable thickness, and is dug up in the way in which we obtain peat in this country. From a chemical analysis, it was found to consist principally of uric acid, partly saturated with lime and ammoniac; and it contains oxalic and phosphoric acids in the same state of combination, as also a quantity of a fatty substance. The origin of the guano is doubtful; it agrees in many particulars with the excrement of birds: but the large masses in which it is obtained are almost incompatible with the idea that it can be derived from a source which appears so inadequate.

Analysis of Tabasheer. By the Same. This is a peculiar substance, found in the joints of the bamboo. It had been previously ascertained that silex was a principal ingredient in it; and the present analysis shews that, in addition to siles, it contains pot-ash and lime.

Memoir on falap. By M. DESFONTAINES.-This valuable article of the Materia Medica was long employed as a purgative, before the nature of the plant was known from which it was procured. It was at length discovered in Mexico, and appears to belong to the genus convolvulus. We have in this paper an accurate botanical description of the plant, and an account of its natural history, accompanied by two engravings.

Result of the different Methods employed to give to Plates and Bars of Steel the greatest degree of Magnetism. By M. CouLOMB.-Referring to the opinions which he has formerly published on this subject, the author remarks that there is a point of saturation, beyond which iron cannot be rendered more magnetical, and that it is of great importance to ascertain with accuracy when the metal has arrived at this condition. The method which he recommends is to suspend the magnet horizontally

Hb 2

rizontally by means of a silken thread, and to observe the number of oscillations that are performed in a given time; the quickness of the oscillatory motion increasing with the intensity of the power. We have afterward some remarks on the best method of magnetizing bars;-the one recommended by M. COULOMB is nearly similar to that which was formerly proposed by Knight.

Memoir on several Species of Unknown Fossils. By M. DESMAREST. In this paper, which is the first of a proposed series, we have a minute account of a fossil considerably resembling the oyster. The memoir is accompanied with illuftrative engravings.

Chemical Observations on the Art of Scouring or Cleansing Stuffs. By J. A. CHAPTAL.-After having remarked that the art of scouring or cleansing stuffs or cloths of all kinds depends en tirely on chemical principles, and requires a very extensive knowlege of the science, in order to explain all the operations that are employed in it, M. CHAPTAL describes in detail the nature of the various kinds of substances by which cloth is injured, and the appropriate means by which they may be removed. Although we do not find that the paper possesses any thing particularly new, it contains much useful information, clearly stated, and well arranged.

Memoir on the Spongy Substance of the Uterus, submitted to some Experiments, by M. TENON.-In these experiments, portions of the spongy substance of the uterus were immersed in different sorts of fluids; as water, alcohol, urine, &c. As might have been predicted, in some the substance was rendered firmer, in consequence of the coagulation of one or more of its constituent parts; while in others it was softened, from the effects of a partial solution. We do not see that the experiments can lead to any important conclusion; and we think that M. TENON's application of them to the living body is quite inadmissible.

Memoir on the Chemical Nature of Smutted Wheat. By MM. FOURCROY and VAUQUELIN.-This substance had been previously submitted to experiment, and had been found to manifest acid properties, but the nature of the acid was not ascertained. From the researches of MM. FOUR CROY and VAUQUELIN, it would seem to be the phosphoric acid, united to ammoniac, magnesia, and lime; the acid, however, existing in excess. It also contains a vegeto-animal matter, a fœtid oil, and a carbonaceous substance. All its natural constituents are quite changed; and it no longer affords gluten, starch, nor sugar.