M. Baume, in his " Elemens de Phar tnacie," has given a table of the degrees of his hydrometer for spirits, indicated by different mixtures of alcohol and pure water, where he says, the spirit made use of gave 37 degrees at the freezing point of water ; and in a column of the table he states the bulk of this spirit, compared with that of an equal weight of water, as 355 to 30. The last proportion answers to a specific gravity of 0.842, very nearly. A mixture of two parts, by weight, of this spirit, with thirty of pure water, gave twelve degrees of the hydrometer at the freezing point. This mixture, therefore, contained 6i parts of Blagden's standard to 100 water ; and by Gilpin's excellent tables, its specific gravity must have been 0.9915. By the same tables these specific gravities of 0.842 and 0.9915 would, at 10° Reaumur, or 55° Fahrenheit, have fallen to 0.832 and 0.9905. Here then are two'spkific gravities of spirit correspond ing with the degrees 12 and 37, whence the following table is constructed.
It may not be amiss to add, however, that in the Philosophical Magazine, Mr. Bingley, the assay-master of the Mint "has given the following numbers as the speci fic gravity of nitric, acid, found to answer to the degrees of an areometer of Baume by actual trial ; temperliture about 60° Fahrenheit. But iris appears to have been
a different instrument, as it was 'graduat ed only from 0 to 50°. ' • With regard to the hydrometer for salts, the learned author of the first part of the "Encyclopedie, Guyton de Mor veal'," who by no means considers this an accurate instrument, affirms, that the sixty-sixth degree corresponds nearly with a specific gravity of 1.848; and as this number lies near the extreme of the scale, I shall use it to deduce the rest.
, .
One of the principal uses of the hydro meter in common life being to determine the gravity of vinous spirits on the mixtures of alcohol, 'which consist of water, an article of no value in a commer cial light, and alcohol, which is of consi derable price, it becomes of importance to, determine how much of each may be contained in any mixture. The following tables, extracted from the large table of Gilpin in the " Philosophical Transac tions," may be considered as of the first authority. They were made with mix tures of water and alcohol, of 0.825 at The alcohol was obtained from malt.