on different Combinations of Fluoric Acid. 369 
combine, it is easy to calculate the proportions of each by 
weight in the respective salts. 
100 Parts consist of 
Ammonia. 
Acid. 
The solid compound 
39.64 
80.32 
The first fluid 
32-9 
67.1 
The second fluid 
42.4 
57 6 
These combinations are curious in many points of view. 
They are the first salts that have been observed liquid, at the 
common temperature of the atmosphere, without containing 
water. And they are additional facts in support of the doc- 
trine of definite proportions, and of the relation of volumes. 
