and attraclive Powers of various f 'altne Sub/lances. 23 
gravities betwixt which that fought for muff lie, and a propor- 
tionate excefs or defect. 
I have added a column of attraction of the nitrous acid to 
water as far as it keeps pace with the increafe of denfity, but 
no farther, as I am unacquainted with the law of its further ■ 
increafe. 
The fpecific gravity of the Itrongeft fpirit of nitre yet made 
is, according to Mr. baume, 1,500; and according to Mr.; 
BERGMAN, 1,586. 
I next proceeded to examine the proportion of acid, water, 
and fixed alkali in nitre, in the fame manner as I had before 
done that in digeftive fait, and found that 100 gr. of perfectly 
dry nitre contain 28,48 gr. acid, 5,2 of water, and 66,32 of 
fixed alkali. 
I fhall now compare the refult of thefe experiments with 
thofe of Mr. homberg. 
The fpecific gravity of the fpirit of nitre which Mr. hom- 
berg made life of was 1,349 ; and of this, he fays, 1 oz. 2 dr„ 
and 36 gr. that is, 621 Troy, are requifite to faturate 1 French 
(oz. 4 72,5 Troy) of dry fait of tartar ; according to my com- 
putation 613 gr. are fufficient ; for this fpecific gravity lies be- 
tween the tabular fpecific gravities by ohfervation 1,362 and 
1,337, and is nearly an arithmetical mean between them. The 
correfponding mathematical fpecific gravity lies betwixt the ta- 
bular quantities 1,315 and 1,286, and is nearly 1,300. Now, 
the proportion of acid and water in this is, 2,629 of acid, and 
8,765 
7,465 of water; for - 1,300 8,765 x .300 
■= 7?4 6 5 water and = ~ 2,629 acid > ' 
and the fum of both is 10,044. Now, fmce 10,5 gr. mild ve- 
getable fixed alkali require 3,55 gr. of acid for their faturation, 
472,5 ; 
