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by water than inflammable air procured by any other procefs, being in fact the very fame thing; and that, in fome cafes, it even diflodges fpirit of nitre and oil of vitriol, which in general appear to be ftronger acids than itself. I have fince obferved that, by giving it more time, it will extract phlogiston from substances from which I at firft concluded that it was not able to do it, as from dry wood, crufts of bread not burnt, dry flesh, and what is more extraordinary from flints. As there was fomething peculiar to itself in the process or refult of each of thefe experiments, it may not be improper to mention them distinctly.

- Pieces of dry.cork wood being put to the acid air, a small quantity remained not imbibed by water, and was inflammable.

Very dry pieces of oak, being exposed to this air a day and a night, after imbibing a confiderable quantity of it, produced air which was inflammable indeed, but in the flightest degree imaginable. It seemed to be very nearly in the state of common air.

A piece of ivory imbibed the acid vapour yery flowly. In a day and a night, however, about half an ounce measure of permanent air was produced, and it was pretty ftrongly inflam

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flammable. The ivory was not difcoloured, but was rendered fuperficially foft, and clammy, tafting very acid.

Pieces of beef, roasted, and made quite dry, but not burnt, abforbed the acid vapour flow ly; and when it had continued in this fituation all night, from five ounce measures of the air, half a measure was permanent, and pretty ftrongly inflammable. This experiment fucceeded a second time exactly in the fame manner; but when I ufed pieces of white dry chicken flesh though I allowed the fame time, and in other refpects the process feemed to go on in the fame manner, I could not per ceive that any part of the remaining air was in flammable.

Some pieces of a whitish kind of flint, bea ing put into a quantity of acid air, imbibed but a very little of it in a day and a night; but of 2 ounce measures of it, about half a measure remained unabforbed by water, and this was ftrongly inflammable, taking fire juft like an equal mixture of inflammable and com, mon air. At another time, however, I could not procure any inflammable air by this means, but to what circumftance thefe different refults were owing I cannot tell.

That

That inflammable air is produced from char coal in acid air I obferved before. I have fince found that it may likewise be procured from pit coal, without being charred.

Inflammable air I had alfo obferved to arise from the exposure of spirit of wine, and various oily fubftances, to the vapour of spirit of falt. I have fince made others of a fimilar nature, and as peculiar circumftances attended fome of these experiments, I fhall recite them more ar large.

Effential oil of mint abforbed this air pretty fast, and presently became of a deep brown colour. When it was taken out of this air it was of the confiftence of treacle, and funk in water, fmelling differently from what it did before; but still the smell of the mint was predominant. Very little or none of the air was fixed, fo as to become inflammable; but more time would probably have produced this effect.

Oil of turpentine was also much thickened, and became of a deep brown colour, by being faturated with acid air.

Ether abforbed acid air very fast, and became first of a turbid white, and then of a yel

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low and brown colour. In one night a confider, able quantity of permanent air was produced, and it was ftrongly inflammable.

Having, at one time, fully faturated a quantity of ether with acid air, I admitted bubbles of common air to it, through the quickfilver, by which it was confined, and obferved that white fumes were made in it, at the entrance of every bubble, for a confiderable time.

At another time, having fully faturated a fmall quantity of ether with acid air, and having left the phial in which it was contained nearly full of the air, and inverted, it was by fome accident overturned; when inftantly, the whole room was filled with a vifible fume, like a white cloud, which had very much the finell of ether but peculiarly offenfive. Opening the door and window of the room, this light cloud filled a long paffage, and another room. In the mean time the ether was feemingly all va nished, but fome time after the furface of the quickfilver in which the experiment had been made was covered with a liquor that tafted very acid; arifing, probably, from the moisture in the atmosphere attracted by the acid vapour with which the ether had been impregnated.

This vifible cloud I attribute to the union of the moisture in the atmosphere with the compound of the acid air and ether. I have fince faturated other quantities of ether with acid air, and found it to be exceedingly volatile, and inflammable. Its exhalation was alfo vifible, but not in so great a degree as in the case abovementioned.

Camphor was prefently reduced into a fluid state by imbibing acid air, but there feemed to, be fomething of a whitish sediment in it. After continuing two days in this fituation I admitted water to it, immediately upon which the camphor refumed its former folid ftate, and to ap pearance, was the very fame fubftance that it had been before; but the tafte of it was acid, and a very small part of the air was permanent, and flightly inflammable.

The acid air feemed to make no impreffion upón a piece of Derbyshire fpar, of a very dark colour, and which, therefore, feemed to contain a good deal of phlogiston.

As the acid air has fo near an affinity with phlogiston, I expected that the fumes of liver of Julphur, which chemifts agree to be phlogistic, would have united with it, fo as to form inflammable air; but I was disappointed in that expecta