on the fpecific Gravities , &c. of Saline Subfiances. 185 
. The foregoing experiments were made at the temperature of 
between 50 and 6o° of Fahrenheit ; but as it may be fuf- 
pe&ed, that the denfity of the above acids is confiderably 
altered at degrees of temperature confiderably different, I en- 
deavoured to find the quantity of this alteration, and to calcu- 
late what this denfity would be at 55% that the quantities of 
acid and water may thereby be inveftigated. 
To this end I took fome dephlogi {Heated fpirit of nitre, and 
examined its fpecific gravity at different degrees of heat, and 
found it as follows : 
at < 
Deg. 
' 3 ° 
46 
86 
1 20 
Sp. gravity. 
1,4653 
i, 45 8 7 
1,4302 
1,4*23 
X’i 
A T ,0 .... f ^ . r n • * • ■ • 
Therefore, the total expanfion of this fpirit of nitre from 
30 to 120 0 , that is, by 90° of heat, was 0,0527 ; for 
1,4650- 1,4123 = ,0527, by which we fee that the dilatations 
are nearly proportional to the degrees of heat : for beginning 
with the firft dilatation from 20 to 46°, that is, by 16 0 of heat 
-H-90 . 0,0527 :: 16 . 0,0093 ; but in reality thefe 16 0 of heat 
afforded a dilatation equal only to 0,0065 ; for 1,4650 - 1,4587 
= 0,0062 ; fo that the difference betwixt the calculated and 
obferved dilatations is only a difference of no confe- 
quence in the prefent cafe, and that might arife from the im- 
merfion of the cold glafs ball filed with mercury in the liquor, 
it being the folid I ufe to try the fpecifc gravity of liquids. In 
the next cafe the difference is ftill lefs ; for fr 90 . 0,0527 :: 
56 . 0,0327 ; but 56° of heat produced in reality a' dilatation 
ofo,o348 for f ,4650 - 1,4302 = 0,0348, fo that the calculation 
is deficient only in 
Vol. LXXII. B b I after. 
