water, M. Lavoifier thinks, is decompofed by the attraction of the oxygen, fo in vegetation it is effected by that of the hydrogen: the laft, he obferves, leaves the oxygen to unite to the coal, and form oils and refins, while the oxygen is copiously disengaged and paffes off through the excretory veffels.

But the most important part of the fubject, and that for which we chiefly introduced it, is the memoir of M. M. Paets, Van Trooftwyk, Deiman, and Cuthbertfon. They first state the queftion in difpute very correctly. It is allowed on both fides, fay they, that in burning inflammable with vital air, not only water but an acid is obtained; 2dly, that this acid could not have exifted in the airs employed, but that it is formed during the inflammation; it is not the fame with the water, which is in lefs quantity the drier the airs are which are burnt. They add, that the adverfaries of the new theory may confider the water as an accidental fubftance, with the fame reafon as its fupporters confider the acid to be so. After fome other observations refpecting the decompofition only having taken place in iron tubes, they proceed to fay, that they are now convinced of the truth of water's being a compound body, from their own experiments. They employed a tube hermetically fealed at one end, and the other opening into a refervoir of distilled water. At the fealed end a golden wire was inferted fo as to project an inch and half into the tube. At the distance of five inches and one-cighth was another wire, which was carried through the open extremity: the firft was connected to the prime conductor of a very powerful electrical machine; the other to the outer furface of a Leyden vial, the button of which communicated with the prime conductor, and which had a fquare foot of coating. As thofe wires, therefore, formed, by means of the water, the electrical circle, the fpark was paffed through the fluid; and foon after fome very powerful fhocks had been given, bubbles of air appeared in the water and gradually collected into larger maffes. When the column was fo great as to extend to the end of the fuperior wire, the whole inflamed, and a very small refiduum was left. On continuing the experiment, the air was again collected and again exploded; but the refiduum was lefs, and after each experiment was ftill farther diminished. They conclude from thefe trials, that by the electrical fhock the water was decompofed, and the ingredients again reunited by the explofion. They obferve that inflammable air and vital air could only explode with the electrical fpark, and neither could be obtained from the atmosphere, through the water, the only fource of air, except from the decompofition. If it be fuppofed to be derived from the electrical spark, this could not furnish the vital air, and the inflammable air would not explode without its affiftance. But it was proper to enquire whether the spark would not produce the inflammable air, and whether the vital air might not be owing to a portion of common air accidentally entangled in the water. To afcertain the first point, they tried

the

the effect of the electrical spark when the tube was filled with oil of vitriol, and the pale nitrous acid. They repeated the fhocks till the air was collected, but would not explode. This might probably be vitriolic acid air or nitrous gas; but as thefe gaffes are abforbed by their refpective acids, this property was fried, though after fome continuance no abforption took place. It was probably, therefore, vital air, and by fending up fome nitrous gas the fufpicion was confirmed. We may, however, be permitted to obferve, that this experiment is by no means decifive, and renders the others doubtful. With all the acids there is much water; and we fee no reason why the water in the acid should not be decompofed: befides, if the acids had been in part decompofed, it might have hindered the explofion, though inflammable air had been present. We do not yet know that the air might have not been a mixture of vital, inflammable and vitriolic acid air. If it was vital air only, it probably arose from the decompofition of the acid; but much of this experiment remains to be elucidated before any confequence can be drawn from it.

The effect of the explosions was afterwards tried with a little variety in the apparatus, but chiefly with the tube and the water carefully exhaufted of its air. The refult was the fame, and the refiduum was one-fixteenth of an inch; but bringing it to the extremity of the thread, and again exploding, it was reduced to one-thirty-second. This was fuffered to escape, and the experiment repeated: the refiduum was then one-twentieth, and after the fecond inflammation one-fortieth. The third time it was one-fortieth, and reduced afterwards to one-fixtieth; the fourth it was one-eightieth and could not be inflamed again. The common air must have been in very fmall proportion even if the whole bubble confifted of it. What then became of the airs produced? did they again form water or acid? This principal part of the queftion is neglected: and the refult is gratuitously fuppofed to have been water, and it is concluded that, the acid was only an accidental production. The advocates for the new theory have attributed the acid to the azote (phlogisticated air) always contained in the oxygen: to this it has been objected, that the purer the oxygen has been, the more acid has been obtained, and by adding azote the acidity is destroyed. To thefe objections our authors anfwer, that the vital has a greater affinity to the inflammable air than the azote, and never combines with the laft, unless there is not a fufficient quantity of hydrogen. If the proportion is, therefore, the proper one, water is the refult; if the oxygen is in excefs, a little acid will be formed by the union of the azote with the excess of vital air. The fame reafon will explain why the addition of azote makes no change in the acidity: if the proportion of the other airs remain, it will only augment the refiduum; but if the proportion of hydrogen be leffened, it will increase the acidity, as Mr. Cavendish found in his experiments. In this reafoning there is apparently much force and much truth.

We must haftily step over the other articles which we pur posed to mention in this sketch: in reality they are of little comparative importance. As we have been speaking of explofions, we may add M. Macor's account of a new and unexpected one. I had precipitated, fays he, with vitriolic æther, fome gold diffolved in aqua regia, made with four parts of nitrous acid and one of fal ammoniac. This mixture was made in a little white vial, which, when full, might contain about half an ounce. As I ufually carried this vial in my pocket in a cafe which contained another full of volatile alkali, I put it in the cafe and returned it to my pocket: I carried it there five or fix days. The feventh day I luckily took it out of my pocket and put it upon a table in a room which I foon after left; in an inftant I heard a found like the report of a cannon. The cafe was burst, and the vials reduced almost to powder, though they were feparated by a little partition: but that which contained the volatile alkali was leaft broken.' We have tranfcribed this paffage to guard our chemical friends against any inattention of a fimilar kind. The pure air of the calx of gold combining with the inflammable air of the æther, probably produced this effect; but it is not easy to affign a reafon why it should have happened when the materials were at reft.

M. Pelletier, in his examination of phofphorus, has lately treat. ed of its union with fulphur. These two bodies eafily unite in the heat of boiling water, and the mixture remains fluid in the heat of from 7° to 10° of Reaumur, (about from 48° to 55° of Fahrenheit) though it might be expected that the union of fulphur would have made the phofphorus more refractory. This fubject, however, he afterwards examines more particularly. Phosphorus alone generally fixes at from 24° to 30° (85° to 100° F.); and at the moment of congealing gives out heat, conftantly 6o (131). The pureft phosphorus congeals at the higheft point. The lowest point at which it fublimes is 76° (203-). When brittle, it is made flexible by melting in water or burning in part the reduefs feems connected with flexibility, and fome phosphorus which we have kept many years in the dark, is perfectly white and brittle: the last point at which the rednefs appeared, was on that fide and in that part where it occafionally received a ray of light. Some fuming orange-coloured ftrong nitrous acid is by the fame means as limpid as the purest water. So powerful is the attraction between air and phlo gifton, or at least phlogifton in its form of light! But to return. Phofphorus, we are informed, boils at 232° of Reaumur, (615°). M. Pelletier then proceeds to the mixture of phofphorus and fulphur. A drachm of the first added to nine grains of the fe cond congealed at the twentieth degree; with double the quantity, the congelation was at 12°; with half a drachm of fulphur at 8°; with equal quantities at 4"; with three drachms of fulphur at 30. The degrees are Reaumur's, but the propor tions only are required; fo that we have not reduced them.

Thefe

These combinations are cafily decompofed in water; the water foon becomes acid and its fmell hepatic. According to the new doctrine it is the water which produces thefe changes by its decomposition; the vital air forming with the radicals an acid, while the inflammable air efcapes, carrying with it a little fulphur. A little phofphorus alfo accompanies it, as the vapour is luminous in the dark.

M. Sage has compared the intenfity of the fire produced by burning equal bulks of the wood of the oak, of its charcoal, the charcoal of peat, and pit-coal. Coal, in our author's opinion, is produced by the action of vitriolic acid on wood; this opinion he endeavours to confirm by experiment; but the greater part of pit-coal contains fome clay, and fometimes, as we have had occafion to remark from baron Born, it occurs in the retracted cavities of lava. But we fhall at a future period return to this fyftem of our author. It is enough now to observe, that the intensity of the fire produced by wood, is to that of the charcoal of the fame wood as 4 to 5. The fire of peat-coal to that of wood is as 4 to 12, and the ratio of the heat produced by pitcoal to that of charcoal of wood is as 4 to 32.

M. Sage's analysis of foffil wood is alfo connected with this fubject. The fofil wood of Iceland, which the Danes call futurbrand, lies in horizontal strata, and the trunks of trees appear often exfoliated, and almost always compressed.' The colour is of a greyish brown: it is brittle, and its fracture frequently difcovers black brilliant veins like jet: the futurbrand indeed appears to be an exhausted jet, for the analysis of each produces nearly the fame refults. The foffil wood of different parts of France differs a little in colour, and in occafionally containing fome martial pyrites. The odour in burning is extremely fœtid. On diftillation, water, accompanied with an hepatic gas of an infupportable ftench, came over, and foon after a limpid acid water, a black, foetid, thick, and heavy oil. The coal was one-fifth of the wood diftilled on burning it gave out the fulphureous acid, and the white light cinder was one-twelfth of the wood; it made a flight effervefcence with acids, and the fmell was hepatic.

The few chemical facts which remain are of fo little importance that we fafely leave them till we again engage in fimilar fubjects: we fhall conclude with a miscellaneous letter of M. Crell, which contains the latest intelligence refpecting the objects treated of, and some matters of real importance.

The most interefting difcovery is undoubtedly the new femimetal which M. Klaproth of Berlin has just discovered in the pechblende and the green glimmer of Saxony (Magellan's Cronstedt, fect. 277. var. 6. p. 56c.)* p. 56c.)* Because it is distinguish

The fection relates to filver mineralifed by fulphurated zinc; but the fecord variety, that which was probably defigned to be pointed out by M. Crell, appears to be added from refemblance only: its nature was evidently not underfood before.

ed

ed from every other, M. Klaproth has called it uranite. It is more difficult to reduce than manganefe, externally greyish, and internally of a clear brown: fpecific gravity 6. 440. Its brilli ancy is not great, and it is fufficiently foft to be fcraped with a file. The calx well calcined and mixed with the necessary flux gives porcelaine of a deep orange colour. In my next letter you shall have a fuller detail. M. Hermstadt continues his labours to extract the acid of tin. He diffolves the tin in pure muriatic acid, and boils the folution with nitrous acid diftilled from manganefe, till no more red vapours arife. The limpid fluid is diftilled till all the muriatic and nitrous acids have disappeared. The white mafs which remains, diffolved in three parts of dif tilled water, is the acid of tin. If this mafs is exposed to a red heat, it changes into a yellow tranfparent matter, without aci dity, and no longer foluble in water, though it regains thefe qualities on being expofed fome weeks to the air+. M. Kunfcmuller thinks that naphtha owe their origin to acids, phlogifticated, by one part, of spirit of wine, and brought to the state of air, and that they are then abforbed by the other part of the fpirit of wine. M. Lowitz has frozen vinegar and diftilled the part which remained fluid from powder of charcoal. This fluid cryftallifes at 195" of Delifle (-21 of Fahrenheit), and the cry. ftallization is regular. At 126° it becomes fluid, and changes to a folid when this heat is leffened. On fuffering all the fluid to drop from the cryftals, we obtain the acid more pure than in any other way. It shows that. Weffendorf's concentrated acid contains nothing heterogeneous, as was formerly fuppofed. A vinegar of the fame ftrength may be obtained by uniting three parts of foda acetata, with eight parts of vitriolated tartar, in which there is an excess of acid, crystallised and distilled with a gentle fire. From the phlegm of the diftillation of vinegar, half the quantity of an anodyne vegetable liquor may be obtained.' (This we have lately explained at length).-The vegetable anodyne liquor may be employed to make vitriolic æther, by adding it to the acid inftead of alcohol, and the product is double of that obtained in the ufual way. M. Weftrumb has often found that in burning dephlogisticated air (drawn from manganefe) and inflammable air, the effect was the same as if he had burn. ed in pure air, fplinters of fir, a fmall candle, or the agaric of the oak; or inflamed pure and well waflied inflammable air together. In all thefe experiments, particularly in that with the mushroom, he obferved a red nitrous vapour, and obtained a nitrous water (a news confirmation of the experiment of Dr. Prieftly, and little favourable to the new doctrine). According to M. Weftrumb alfo, vinegar may be procured from acids, rich in phlogifton, by repeated diftillations only; viz. from the acids of lemons, fugar, and from empyreumatic acids: from whence in thefe inftances do they obtain their oxygen?'

It is certainly, therefore, not the base of tin, or the base is not an acid. 61% of Far. but there is probably fome error of the prefs in the original.

MONTHLY