Inflammable air I had also observed to arise from the exposure of spirit of wine, and various _oily_ substances, to the vapour of spirit of salt. I have since made others of a similar nature, and as peculiar circumstances attended some of these experiments, I shall recite them more at large. _Essential oil of mint_ absorbed this air pretty fast, and presently became of a deep brown colour. When it was taken out of this air it was of the consistence of treacle, and sunk in water, smelling differently from what it did before; but still the smell of the mint was predominant. Very little or none of the air was fixed, so 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 saturated with acid air. _Ether_ absorbed acid air very fast, and became first of a turbid white, and then of a yellow and brown colour. In one night a considerable quantity of permanent air was produced, and it was strongly inflammable. Having, at one time, fully saturated a quantity of ether with acid air, I admitted bubbles of common air to it, through the quicksilver, by which it was confined, and observed that white fumes were made in it, at the entrance of every bubble, for a considerable time. At another time, having fully saturated a small 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 some accident overturned; when, instantly, the whole room was filled with a visible fume, like a white cloud, which had very much the smell of ether, but peculiarly offensive. Opening the door and window of the room, this light cloud filled a long passage, and another room. In the mean time the ether was seemingly all vanished, but some time after the surface of the quicksilver in which the experiment had been made was covered with a liquor that tasted very acid; arising, probably, from the moisture in the atmosphere attracted by the acid vapour with which the ether had been impregnated. This visible cloud I attribute to the union of the moisture in the atmosphere with the compound of the acid air and ether. I have since saturated other quantities of ether with acid air, and found it to be exceedingly volatile, and inflammable. Its exhalation was also visible, but not in so great a degree as in the case above mentioned. _Camphor_ was presently reduced into a fluid state by imbibing acid air, but there seemed to be something of a whitish sediment in it. After continuing two days in this situation I admitted water to it; immediately upon which the camphor resumed its former solid state, and, to appearance, was the very same substance that it had been before; but the taste of it was acid, and a very small part of the air was permanent, and slightly inflammable.