2? Mr. xirwan’s Experiments , &c. on the fpecific Gravities 
fpecific gravity by obfervation is 1,819, will be found to be 
= 3,664 ; but of this 2,95 gr. are the lofs of the water it 
contains, and the remainder 0,714 * are the Lofs of the mere 
<2 r r m 
acid part. Then, n 4,9649 is nearly the true fpecific gra- 
vity of the pure vitriolic acid. 
I then found the true increafe of denfity arifing from the 
union of the vitriolic acid and water in the foregoing mixtures, 
and obferved, that in oil of vitriol, whofe fpecific gravity was 
1,771, it was 0,84, and in that whofe fpecific gravity was 
1,719, it was 0,100. 
To obtain a fynthetical proof of thefe deductions, I compared 
them with the fpecific gravities of the firft mixtures I had made ; 
for if thefe deductions were true, the mathematical fpecific gra- 
vities, and the accrued denfities, added to each other, (hould 
amount to the fame quantity as the fpecific gravities by obferva- 
tion ; and this I found to happen very nearly ; for in the firft 
experiment, where 2519,75 gr. of oil of vitriol, whofe fpecific 
gravity was 1,819, were mixed with 180 gr. of water, that oil 
of vitriol contained by my calculation 1376,171 gr. of acid and 
1143,597 gr. of water, befides the 180 gr. of water- that were 
• • 1376 1 7 1 
added to it, the lofs of the acid was = 277,22.. The 
whole quantity of oil of vitriol was 2699,75 gr. then the 
fum of the lofles was 1600,81 ; and therefore the mathemati- 
cal fpecific gravity — 1,686 ; to which, adding ,084 the 
degree of accrued denfity, the fpecific gravity by obfervation 
* By miflake,.the following calculations were made on the fuppofition that the 
lofs was 0,715 ; the difference being immaterial, the calculations were not 
icpeated. 
t Ihould 
