32 Mr. kir w an* s Experiments , &c. on the fpecijic Gravities 
ca e the excefs of weight will be very nearly fuch as he deter- 
mined it: for 10,5 . 8,31:472,5 . 373,3. Now, the whole 
weight of his nitre was 560,2, as I have above fhewn : then 
560,2 - 373,3 = 1 16,9, which is only 4 gr. more than he de- 
termined it. 
Hence he inferred, that 1 oz,. (472,5 gr. Troy) of this oil 
of vitriol contains 291,7 gr. of acid. By my computation it 
contains but 213,3; but it muft be confidered, he made no 
allowance for the water contained in tartar vitriolate, and ima- 
gined the whole of the increafe of weight proceeded from the 
acid that is united in it to the fixed alkali. Now the aqueous 
part iii 560 gr. of tartar vitriolate amounts to 37 gr. the re- 
maining difference may be attributed to the different •degrees of 
deficcation, &c. 
OF THE ACETOUS ACID. 
I have made no experiment on this acid ; but, by calculating 
from the experiment of Mr. hoMBERG, I find the fpecific gra- 
vity of the pure acetous acid, free from fuperfluous water* 
fhould be 2,130. It is probable, its affinity to water is not 
ftrong enough to caule any irregular increafe in its denfity, at 
lead: that can be exprefled by three decimals ; and hence its pro- 
portion of acid and water may always be calculated from its 
fpecific gravity and abfolute weight. 
100 parts of foliated tartar, or (as it ffiould rather be called) 
acetous tartar, contain well dried 32 of fixed alkali, 19 of acid, 
and 49 parts of water. 
The fpecific gravity of the flrongefl concentrated vinegar yet 
made is 1 ,069. 
It 
