470 M E M O I R S of fh^ 
drachms i8 grains of acid fait 5 fo for the impregnation of an 
ounce of fair of tartar, there was poured upon it two ounces 
five drachms cf fpirit of fait 5 and the increafe after the eva- 
poration has been found three drachms 14 grains 5 and there- 
fore an ounce of fpirit of fait contains one drachm 1 5 grains of 
acid fait : Upon an ounce of fait of tartar was poured five 
drachms of the oil of vitriol ; the increafe was found three 
drachms five grains j therefore an ounce of oil of vitriol contains 
three drachms 6^ grains of acid lalt; Upon an ounce of fait 
of tartar was poured of Aquafortis an ounce two drachms 30 
grains; the increafe was found three drachms fix grains^ there- 
fore an ounce of Aqua fort is contains two drachms z6 grains 
of acid fait: Upon an ounce of fait of tartar was -poured dif- 
tilled vinegar 14 drachms, the increafe was found three drachms, 
5(J grains, therefore an ounce of diftilled vinegar contains 18 
grains of acid fait : It appears by this table, that the quantity 
of acid fait for faturating the fait of tartar is nearly the fame, 
tho' the quantity of acid liquors Hiould be very different 5 it 
is only the acid of vinegar, whereof the fait of tartar retains 
more than it does of the others,^ which M. Romberg attributes 
to the fubtilty of the particles of the vegetable acid, that 
have been very much divided by the alterations in the fermen- 
tation of the liquors of the plants, ^c, of the wine, and alfo 
in the diftillation, which alterations the mineral acid has not 
received j that the vegetable acid by its fubtilty of particles can 
impregnate a greater quantity of liquor, than the fame quan- 
tity of mineral acid, and fo is more eafily fublimed by the fire 
than the others. 
By thefe obfervations M. Homberg makes the reafon of fomc 
cafes evident, which would otherwife be difficult to be ex- 
plained without them; as it is well known that one ounce of 
^qna Regia compounded with the fpirit of nitre and ar- 
moniac-lalt diffolves twice more gold, than an ounce of the 
fpirit of fait can do ; chemifts afcribe that effedl: to the foftnefs 
of the points of one acid, and to the hardnefs of thofe of the 
other; when thele obfervations (hew evidently that the fpirit of 
riitre contains twice more acid fait, than the little volume of 
fpirit of fait, and point out at the fame time the true caufe of 
this effeifl : M. Homberg alfo (hew'd how that by comparing thefe 
two tables we may know the quantity of acid fait contained in 
any acid fpirir, in the following manner ; he took an acid fpirit, 
as fpirit of nitre, which he weighed by his arccometer, and at 
the fame time he weighed alfo diftilled water (for the weight 
of 
