acetite of lead, (which latter is easily soluble in acetous acid,) we may be sure that it contains malate of lime.

The colours of the precipitate, which the juices of the different plants abovementioned (and others) yield with solution of acetite of lead, appeared in some instances beautiful and solid enough to deserve trial as paints. That which came from the sedum acre is yellow; from the arum maculatum, the most beautiful green.

On the Identity of the pyromucous, pyroligneous, and pyrotartarous Acids: By M. M. FOURCROY and VAUQUELIN.

This most important paper is introduced by observations on the multiplicity of the vegetable acids. The characters assigned to those mentioned in the title of the paper are there reviewed, and shewn to be indistinct. In the course of researches on the nature of cork, a red empyreumatic matter was obtained by distillation, which presented all the sensible characters of the pyroligneous acid. On rectifying this liquid, combining it with alkalis, and then recompounding the salt with weak sulphuric acid, the liquor obtained presented every character of true acetous acid. Hence we may presume that pyroligneous acid, however procured, was no other than the acetous; and that the two other empyreumatic acids were of the same

nature.

Pyromucous acid from sugar, on being combined with lime and then treated with weak sulphuric acid, afforded a liquid with a very strong acetous smell; which combined with potash into acetite of potash, of a dark colour, but turning perfectly white on being filtered hot through powdered charcoal.

The other two acids presenting the same phænomena, it remained only to corroborate the analysis by synthesis; and this was easily effected by adding the empyreumatic oils of the respective bodies to acetous acid. It is to the solubility of these oils in acetous acid, that the odour so easily contracted and so tenaciously preserved by vinegar, is to be attributed.

In consequence of these experiments, we have attained to the knowlege of four modes of producing vinegar, viz. destructive distillation, yielding an empyreumatic acetous acid: - the addition of strong acids to vegetable compounds;-(the malic and oxalic acids are in this case formed at the same time, and the acetous acid is very weak from the water, which, as the writers say, is also formed;)—the acetous fermentation ;—(this product is spirituous;) and a peculiar fermentation, independent of wine, to which animal liquids, and urine in particular, are subject. This acid is always accompanied by ammonia.

Extract of a Memoir by M. VAN MONS, on the Rhus radicans; by M. B. LA GRANGE.

We are told that M. Bosc ascertained the identity of the Rh. rad. and the Rh.toxicodendron during his residence in America, where it is called the small-leaved poison oak, and where its very touch is avoided. M. VAN MONs attributes the deleterious effects of this vegetable to a gazeous substance, which exudes from the living plant;-the dried and even the withered leaves never occasioning any inconvenience. The sufferings experienced by those who break the stem, or warm themselves at a fire of this poison-oak, arise from the same emanation, or from the gazeous base condensed. In the sun, this plant yields almost pure oxygen gas; in the night, a mixture of hydrogen

M. VAN MONS concludes, from his experiments, that the predominating principle of the Rh. radicans is a very combustible hydrocarbonate. The use of it in palsy is imputed to M. Du Fresnoy. The Rh. toxicodendron has been represented in this country as applicable to the same purpose.

The remainder of this paper respects the best form for the administration of this remedy; and a cold extract is recommended:-but nothing is said to prove the superiority of any preparation to the dried powder.

M. BARRUEL renders justice, in the next paper, to the claims of M. Guyton respecting synoptic tables.

Chemical Observation by M. CADET GASSICOURT.-Oxalic acid formed accidentally in a mixture of sulfuric acid and rectified alcohol, left in a cool place for about 30 hours.

M. VON CRELL on the Decomposition of boracic Acid.-This paper was first published in our Philos. Transactions. See Rev. Vol. xxx. N. S. p. 148.

Memoir on several new Properties of phosphorated hydrogen Gas. By M. RAYMOND.

Water fresh distilled dissolves a little less than 1-4th of its bulk. The solution is of the colour of roll brimstone; the taste is extremely bitter, vapid, and disagreeable; the smell is strong and unpleasant;-and it does not appear luminous in the dark. When left to stand in contact with the atmosphere, red oxyd of phosphorus is deposited, and hydrogen gas disengaged.

The hydro-phosphoreous liquor does not redden vegetable blues. It precipitates most metals from acids, in the state of metallic phosphures.

Treatise

Treatise on Wines, by M. CHAPTAL; extracted from the 10th Vol. of Rogers's Course of Agriculture.

This re-published paper appears to us to be calculated rather to diffuse among a particular class of people, in a particular country, the knowledge of facts already ascertained, than to extend the science of chemistry. Its interest being therefore local, the propriety of its appearance in a work of the nature of the Chemical Annals may well be doubted. That our readers, however, may be enabled to form their own judgment, we shall extract one article: viz. the Formation of Alcohol.

The saccharine principle makes one of the essential characters of must. This principle disappears on fermentation, and is re-placed by the alcohol; a substance essential to wine. As the end of the spirituous fermentation is to produce alcohol by destroying the saccharine principle, the formation of the one is in proportion to the destruction of the other; and the alcohol will have been more abundant, according as the saccharine principle shall have been plentiful. Hence the quantity of alcohol may be increased at pleasure, by adding sugar to the

must.

Hence the nature of the matter in fermentation varies every moment :-but, as there is in fermentation a continual progres sion, these changes may be followed, and be exhibited as invariable signs of the different states through which the fermenting material passes: 1. The must has a peculiar sweetish smell. 2. Its taste is more or less saccharine. 3. It is thicker, and its consistence varies as the grapes are more or less ripe, more or less saccharine. The difference is from 75° to 40° by the arcometer. Scarcely does the fermentative process begin, when all the characters change: -it has a pungent smell, from the disengagement of carbonic acid :-the taste, though as yet very sweet, has a mixture of pungency :-the consistence lessens; -and the liquor, which had hitherto presented an uniform whole, shews flocculi, which become more and more insoluble.

By degrees, the saccharine taste grows fainter, and the vinous stronger; the liquor becomes sensibly thinner; the flocculi are more completely detached; the smell of alcohol is perceptible at a great distance; at length arrives a moment at which the saccharine principle is no longer sensible; and the smell and taste indicate alcohol only. However, all the saccharine principle is not destroyed. The farther decomposition of this substance is effected by the slow fermentation which takes place in the vessels; and when the fermentation is complete, no sugar any longer exists. The liquor has gained in fluidity, Mm 3

and

and exhibits merely alcohol mixed with a little extractive and colouring matter.

Such is the manner of a paper which occupies 130 pages in three numbers, and which is destined to occupy more space in the succeeding: but it should certainly have been published in a separate pamphlet, for the use of those whom it might

concern.

Description of a Support applicable to Balances of all Dimensions by M. PRONY.-In the instrument here described and figured, this ingenious mechanic has furnished experimenters with a most commodious and by no means expensive mode of avoiding that tedious operation, balancing by hand.

Observations on the Constitution of different Kinds of Steel.— In this paper, which M. GAZERAU calls a very brief abstract from his experiments, but none of which are particularized, he endeavours to shew that the natural steel, or steel from the first smelting, is an allay of pure iron with manganese, as well as with carbon.

In a letter, M. ABILGAARD shortly states, on the faith of experiments not perhaps conducted with sufficient accuracy, that 148 grains of the charcoal of venous blood were required to detonate 480 grains of nitre, and only 119 of arterial blood.

Reclamation relative to the Invention of Parachutes.-M. LE NORMAND here claims the invention of the name and the thing, of which M. Montgolfier has hitherto enjoyed the honour. The Editors admit the claim.

Memoir on the Fabrication of the Wedgwood Pyrometric Pieces: by M. GAZERAU.-There is now, or there was very lately, (if we be not misinformed,) at the manufactory itself at Etruria, a difficulty in finding clay fit for these pieces. M. GAZERAU is led by his numerous researches to prescribe the use of a clay containing at least 34 parts in 100 of alumine; and the addition of siliceous earth enough to render the pieces at least as refractory as those of Wedgwood.

Analysis of a stone named Gadolinite, with an Account of some of the roperties of the new Earth which it contains: by M. VAUQUELIN.

It is known to chemists that, about six years ago, M. Gadolin discovered the earth here in question; and that M. Ekeberg has since employed himself in analysing the Swedish mineral which affords it. To the earth itself he gave the name of Yttria, from Ytterby, the place at which the mineral is obtained.

M. VAUQUELIN finds the new earth united in the Gadolinite to silex, oxydated iron, oxyd of manganese, and lime. He separated

parated it in two different ways; of which it will be sufficient One hundred parts of gadolinite being for us to report one. dissolved in diluted nitrous acid, he then evaporated; applying a brisk heat at last to effect the complete decomposition of the nitrate of iron. On redissolution in water, he obtained the peculiar earth dissolved, the silex and iron being detached. To separate the latter of these from the former, the mixture is boiled in rather strong marine acid; and the iron is disunited by filtration. Ammonia is then added to the nitrous solution; this leaves the lime, and separates the new earth These latter are then dissolved a third with the manganese. time; and a solution of hydro-sulfure of potash is gradually added, to separate only the metallic parts.

This earth differs from alumine and glucine in not being soJuble in caustic fixed alkali. It combines rapidly, and with heat, with sulfuric acid. The salt has an astringent taste at first, and afterward a sweet flavour like a salt of lead; which is distinguishable from that of salt of glucine.-Yttria forms de1quescent salts with nitrous and muriatic acids. - Prussiate of potash, chrystallized, and re-dissolved in water, causes a white grainy deposition in solutions of this earth in acids; which is not the case with solutions of glucine.

Analysis of the mineral Waters of Tongres: By M. PAYSSÉ.These waters are remarkable for the quantity of carbonate of manganese which they contain.

M. H. VAN MONS's Critical Examination of Wigleb's Commentary on the Conversion of Steam into Air; translated from the Latin by M. LE CLERC.

The numerous papers on the effect of transmitting steam through red hot tubes, which have been published, have appeared to us to prove so clearly that (in this way at least) water is not convertible into air, but that the air obtained arises from the porosity of the vessels, or from other sources of error, that we did not look for another discussion of the old arguments.

Analysis of the Honey-stone: By M. VAUQUELIN.

To obtain the acid, discovered by M. M. Abich and Lampadius to exist in this stone, it was digested with carbonate of potash, and then separated by sulphuric acid. M. VAUQUELIN, confessing indeed that his experiments are not satisfactory to himself, declares that he has only observed the following points of difference between the acid here in question and the oxalic. -The precipitate which the acid of the honey-stone occasions in solution of sulfate of lime, is longer in appearing, and has a powdery instead of a chrystalline appearance. It tastes

less