I next proceeded to examine the properties of the dif ferent substances into which I had separated Richter's alcohol, but the time I had now left for this purpose was too short for making much progress in this inquiry; a few only of their habitudes with water, and with one another, were all that I had time to examine ; even these I could examine only imperfectly.
The lowermost stratum, or nearly colourless fluid, which I have called alcohol, had no flavour, and produ ced on the organ of smell only a sharp pungent sensation It has the remarkable property of smoking when expo sed to the air, and, when diluted with water, it differ: considerably in taste from common diluted spirit of wine.
I have made no experiments to ascertain the specifi' gravity of this alcohol. It may at first sight be conclu ded, that, hy being deprived of its impurities, which arc evidently specifically lighter than it, this alcohol would have its specific gravity increased : such a conclusion, however, would be obviously rash ; for, since these impu rities were, without doubt, previously in combination with the alcohol, and when mixed with it again enter into that state, and since, by this kind of combination, the mean specific gravity is generally altered, most frequently in creased—supposing that this combination follows the more general law, the increase may be either greater or less than the diminution occasioned by the lighter impu rities ; and therefore, for any thing we at present know, the specific gravity of this alcohol may be either greater or less than that of the compound from which it is ob tained.
The pale yellow substance, or second stratum, has a pungent taste, leaving an impression of sweetness. It has a very strong but agreeable smell. When mixed with the alcohol, and diluted with water, it has vers much the flavour of the better kinds of highland whisks It readily dissolves in water, and communicates to that fluid its peculiar flavour.
The pale yellowish green substance which composes the uppermost stratum, has a strong and very offensive smell, and a very sharp nauseous taste. It dissolves in alcohol, to which it communicates its peculiar flavour ; its disagreeable smell is considerably heightened by this combination. It dissolves in water, though less readily
than the substance last treated of. The compound, when much diluted and heated, has very much the flavour of the low wine of our lowland distillers, at the time when it issues from the still.
The two last mentioned substances, or those of which the two upper strata are composed, when mixed together and greatly diluted with water, have very nearly the fla vour of alcohol. They have rather more volatility than water ; for when half of a solution of them has been distilled over, the distilled part has a much stronger smell than that which remains in the retort. The kind of smell, however, of both portions is the same, which shows that these impurities cannot be separated by dis tillation.
It may be proper to mention, that from the circum stance of my sense of smell having been for some time extremely obtuse, I have been under the necessity of trusting to others for the facts regarding the flavour of these new substances and mixtures. From the ut iform ity of the reports, however, which I have received from different persons, 1 have no doubt that these facts are correct.
Besides that from which I filled the thermometer in the first experiment, I have operated on alcohol of the specific gravities 802, 797, and 784. The specific gravi ty of the last was taken when its temperature was 66°, and it is probably the most concentrated that has eve: been obtained. But with alcohol of all these differen strengths, the general results were similar. In alcohol obtained from different sources, the proportions of the impurities were different, both with regard to the pure. alcohol, and to one another, but I has e w that did not contain both.
From tl,csc experiments I think it is ascertained, 1st, That the strongest alcohol which we are able to obtabi, may be frozen by the method alluded to.
2d, That this alcohol contains at least two foreign substances, are highly volatile, and, so far as is known, can only be separated by freezing.
3d. That it is to these substances that alcohol owes its peculiar flavour, and that, according as the one or other predominates, the flavour of the alcohol is agreeable or otherwise.