« ПредыдущаяПродолжить »
same ;-that the metallic oxyds are not equally fit to attract and fix the vegetables : some, which attract them the most readily, retaining them the most feebly ;--and lastly, that the oxyd of tungsten has a decided advantage over the others.
Letter from S. FABRONI, to M. Van Mons. The author here endeavours to prove that alcohol is not the product of the vinous fermentation, but of distillation. He thinks that this is demonstrated by an experiment, in which one hundredth part of alcohol introduced into a quantity of wine can be made to appear : whereas the wine itself, though it will afford by distillation 20 or 25 per cent. of alcohol, does not yield an atom when treated according to the same method. The method is to introduce new wine into a measure graduated into 100 parts; to add as much potash in powder, as it has been previously determined will be necessary to precipitate all the resinous colouring matter; and the alcohol which has been added will float distinctly on the alkaline solution. The author prescribes the separation of the colouring matter, merely to render the result more sensible; and he orders new wine, because the temperature of the air may determine the production of alcohol in the bottles.
Review of a Work entitled Tableau du Regne Vegetal, i. e. Picture of the Vegetable Kingdom, according to the Method of
Jussieu. By G. P. VENTENAT. 4 vols. 8vo. with 24 platos. The reviewer, M. FOURCROY, speaks in the highest terms of this introduction to botany; which is also represented as an introduction to the physiology of plants, and in some sort to rural economy.
Analysis of the Bark of the IVhite Willow. By M. BARTHOLDI. The white willow bark, (long since proposed in this country as a substitute for Peruvian bark, in some cases, and superseded here by the more powerful bark of the broadleaved willow,) was employed with advantage at Colmar; and the physician to the hospital desired the writer of this paper to undertake the present analysis ; which is, we think, a very common-place performance. : Memoir on the fabrication of Crayons of Paste of Sanguine, (bloodstone, hæmatites) employed for drawing. By A. F. Zomer. This is a very interesting paper. The author describes with accuracy the proper proportions, and the modes of proceeding, in order to make good crayons.
Note by A. N. SCHERER, on the Extraction of Sugar from the Beet. The plant in question is stated by M. Van Mons to be the Beta Cicla, not the B. vulgaris. Thirty-two pounds and a half of the root are said to have given three pounds and three
ounces of crude sugar, of a light-brown colour; and eight pounds of refined sugar are calculated to be produced from 100 of the root: M. Achard has since published his method at full length. Axsfuhrliche Beschreiburg, Berlin, 1799, 8vo. pp. 63. He lays much stress on the mode of culture, and says that crude sugar can be procured at about 3d. a pound; which, if true, is intelligence of no small concern to our commercial interest, and to the slavc-trade.
Account of a Work entitled the Assayer's Manual, by M. VauQUELIN. --These instructions are strongly commended by the author of the article, M. B. LA GRANGE.; and the well-known character of the writer of the manual inclines us to suppose that the commendations are well bestowed.
Account of a Work by M. VAN MARUM, containing the Description of some new or improved Apparatuses belonging to Teyler's Foundation, and of Experiments made with the Apparatuses.These apparatuses and experiments were contrived with the view of repeating, on a large scale and with rigorous exactDess, certain processes already published by M. Lavasier, as íundamental to the pneumatic theory.
Thus far had we written, and were on the point of dispatching our manuscript to the printer, when we received the NinetyFirst Number : of which the contents make ample amends for the barrenness of its two predecessors,
On the Décomposition of Muriat of Scła by Oxyd of Lead, by M. VAUQUELIN.-The explanations of this phænomenon, hitherto given, are quite unsatisfactory. The alleged superior affinity of the oxyd is refuted by the decomposition of muriat of lead by caustic soda; and as to the carbonic acid in lithaige, that has nothing to do with the phenomenon, as appears from the absolute inactivity of carbonat of lead on muriat of soda.M. VAUQUELIN has found also that the decomposition of the neutral sait is complete, when there is enough of the metallic oxyd. His experiments lead him to conclude that the litharge, which has served to decompose muriat of soda, is a muriat of lend with excess of oxyd; that the caustic alkalis do not decompose this salt, but merely dissolve it; that it is in virtue of the affinity of muriat of lead to this oxyd, that litharge decompounds sea-salt ;--that it is the excess of oxyd above that in ordinary muriat of lead, which communicates to the salt the property of assu!ning a yellow colour, on the application of heat, which does not happen to common muriat of lead ;- that it is this excess which renders this muriat of lead almost insoluble is water; and that this excess is dissolved by nitric acid to
form nitrat of lead, while it leaves the neutral muriat of lead undissolved.
Extract from Scherer's Journal of Chemistry.--As we mean to present our readers with an extract of all that is interesting in Scherer, we pass over this article.
Extract from a Memoir by. M. VACQUELIN on the Sap of Ve. getables.-M. VAUQUELIN examined the saps (collected at dif. ferent times from each) of the common elm (ulmus campestris), of the service (sorbus aucuparia), of the beech (fagus sylv.), of the birch (betula alba), of the carpinus sylv., and of the mulherry. He found them to differ considerably in their composition :- but it is remarkable that the acetous acid, in greater or less proportion, is common to them all. The alkalis in the first two subjects do not exist in a state of combination with the vegetable matter, but in that of salts united with the ace: tous and carbonic acids; and their developement is owing to the decomposition of the acetous acid. The sap of the beech differs from that of the elm and service in containing no carbonat of lime, and in presenting acetous acid disengaged ; ag also tannin, and Gallic acid. From the sap of the birch, no white sugar could be separated; whence the writer concludes that it contains no proper sugar.-From the sap of the mulberry, in the course of a month, a number of chrystals of nitrat of potash were deposited.
The memoir itself is said to be sold separately, and to prea sent a number of new facts, which the author of the extract has passed unnoticed.
Observations on the Manner in which the Mountains in the Cevennes are rendered fertile.-By M. K. CHAPTAL. This is not, -as might be expected from such a title, occurring in such a work,-an account of chemical means of rendering soil fertile, but of mechanical means of detaining, and causing to be de. posited, the soil washed from the higher parts of the mountains. The contrivances here described consist of a number, of walls built without cement, in such a direction as to cause some stagnation in the descending torrents, without stopping it entirely. Indeed, without allowing it some vent, they would be swept away; which disaster does sometimes happen --Such is the effect of industry exerted in this particular mode, that a surface of territory, which formerly would have been inade. quate to the support of a single family of savages, now main. tains two or three hundred thousand inhabitants.
Extract from a Memoir, the first of a Series, contributing to the natural, chemical, and medical History of Human Urine ; containe
ing some new Facts, relative to its Analysis and its spontaneous Alteration, by M.M. FOURCROY and VAUQUELIN.- This account of a truly important investigation will excite, in the highest degree, the curiosity of the needical and philosophical reader. It is shewn that the means hitherto employed have given many uncertain results, and that many errors have been committed. The materials constituting urine act on one another while the chemist is at work, and produce a liquid quite different from that which is discharged from the body. A small increase of temperature occasions, in a few moments, the formation of ammonia and carbonic acid ; and these substances are produced by the spontaneous alteration of the fluid, independently of artificial heat.
From observations on the putrid decomposition of urine, made with the view of illustrating the production of calculi, it appears that the authors have no idea of an opinion which has obtained credit in this country, and which it is of great consequence to the inquiry to establish or overturn. We mean the doctrine of the secretion of calculous matter, in opposition to that of its deposition.
Human urine contains, according to the present writers, ten principal or constant ingredients, viz. muriat of soda, muriat of aminonia, acid phosphat of lime, phosphat of magnesia, phosphat of soda, phosphat of ammonia, uric acid, ben. zoic acid, jelly, and albumine, and the specific matter of urine, denominated here urée ; of the nature of which, a particular account will be given in a future paper. In the present, it is said that to this matter the urine owes the property of becoming, by sporitaneous fermentation, a fluid so different from what it is when first voided, as to contain nine new ingre. dients.
Extract from the Procès-verbal of the Experiments made in teza Stercessive Years, at the Polytechnic School, on the Combustion of the Diamond. By M. GUYTON.-Much as the chemical world has been interested in the modern experiments on this prince of gems, the labours of M. GUYTON will excite not less sensation than those of his ablest predecessors. We cannot, for want of the engraving, undertake to impart to the English public a complete view of the manner of proceeding : but the result, which is more important, 'comes out as follows:- The dia. mond, in forming carbonic acid by combustion, consumes n.uch inore oxygen gas than an equal weight of charcoal does; not reckoning the residuary ashes from the charcoal. The proportion of ingredients in the acid, so far from being 0,28 of carbon and 0,72 of oxyger, turn out 17,88 of the former, and 82.12 of tlie latter.
It is pure
Hence the diamond is not crystalized charcoal. Carbon.- What, then, is charcoal ?--principally an oxyd of carbon; and there are other oxyds of carbon, containing less oxygen than charcoal, such as the incombustible coal or anthracolite, coaks, and plumbago. During combustion, the diamond actually shewed, in the changes of colour which it underwent, no indistinct signs of oxydation.
All these inferences rest on the accuracy of M. GUYTON'S manipulations; which were difficult indeed, but which no individual is perhaps more capable of performing without error. This paper will doubtless create many attempts to produce diamond powder from charcoal, by de-oxydation.
We have just received No. 92, but too late for farther notice.
Art. XV. Von dem Perkinismus, &c. i. e. On Perkinism, or the
Metallic Needles of Dr. Perkins : with American Testimonies, and Experiments of (some) Copenhagen Physicians, published by M.M. HERHOLDT and Raru; with Observations by J. C. TODE, M.D. 8vo. Pp. 108. Copenhagen. 1798.
"He first part of this publication consists of a tract by Dr.
Perkins himself, entitled, Certificates of the Efficacy of Dr. Perkins's Patent Métallic Instruments ; Newbury Port, 1796 ; and it is matter of some surprise to us, that the Copenhagen faculty were not satisfied of the inutility of this pretended discovery, by the very testimonies produced in the original work to demonstrate its importance. Certainly, if, in some instances, want of precision in the statement of cases, so great as to reader it nearly impossible to divine their nuture; and if, in others, assertions contrary to the very nature of things, joined to a confused and almost unintelligibie set of directions, had been sufficient to damp the ardour of the philosophical contribuiors to the tract before us, we should not now have to make a report to the public of the result of their joint labours.
These contributors are not sewer than eleven ; some of them presenting names which are familiar to all who are interested in physical and medical science, viz. Professors sibile gaard, Tode, Schumacher, and Bang; Surgeons Kicrogberg, Blech, Jacobsen, Han, Herholdt, As vassar, and Rafiu.
The experiments were made witli needles of iron, brass, silver, zinc, copper, and lead ; and some with pointed pieces of ebony and ivory. ---Publications that challenge attention in the name of matters of fact have so indefeasible a claim; the
* We suppose the original axedlea to be mere sharpened bits of iron and brass. Rev.