and attraBive Powers of various f aline Subftances. ^5 
5thiy. That, knowing the quantity of fixed alkali in oil of 
tartar, we may determine the quantity of real pure acid in any 
other acid fubftance that is difficultly decompofed, as the feda- 
tif acid, and thofe of vegetables and animals; for 10,5 gr. of 
the mild alkali will always be fatu rated by 3,55 gr. of real acid: 
and reciprocally, the quantity of acid in any acid liquor being 
known, the quantity of real alkali in any vegetable alkaline 
liquor may be found. 
OF THE SPECIFIC GRAVITY OF FIXED AIR 
IN ITS FIXED STATE. 
Being defirous to know the fpecific gravity of fome fub- 
ftances which are difficultly procured, or at leaf! preferred for 
airy time, free, from fixed air, fuch as fixed and volatile alkalies, 
X was induced to feek the fpecific gravity of the former in its 
fixed ftate as of an element neceflary to the calculation of the 
latter ; it being very evident, that its denfity, in its fixed Rate, 
mu ft be very different from that which it poffefles in its fluid 
elaftic ftate. 
I therefore took a piece of white marble, of the pureft kind, 
which weighed 440,25 gr. and weighing it in water, found it 
to lofe 162 gr. ; its fpecific gravity was therefore 2,7175. 
Of this marble, reduced to a fine powder, I put 180 gr. 
into a phial, and expelling the fixed air by the dilute vitriolic 
acid and heat, I found its quantity amount to 105,28 cubic 
inches ; the thermometer being at 6 5 0 , and the barometer be- 
tween 29 and 30 inches, this bulk of air would, at 55 0 of 
Fahrenheit, occupy but 102,4 cubic inches ; at which tem- 
perature, according to the experiment of Mr. fontana, a 
F 2 cubic 
