RESEARCHES UPON SALICIN. 
141 
separately obtained for the vapor of hydrated benzoic acid, is 
exactly the same as that which I found for the hyduretof sali- 
cyle. From this, each volume of the vapor of this latter 
should contain: 
7 of the vapor of carbon, =2.9512 
3 " " =0.2064 
1 " " =1.1026 
1 " hyduret of salicyle, =4.2602 
the same as crystallized benzoic acid. 
Chemistry exhibits few of such perfect cases of isomerism, 
where two substances, totally distinct, have at the same time a 
like elementary composition, and a similar condensation of 
their elements in the state of vapor. We shall likewise see 
that the combinations which result from the union of the hy- 
duret of salicyle with bases, have the same composition as the 
corresponding benzoates considered as anhydrous. 
According to the theory most generally received by che- 
mists, benzoic acid is regarded as an oxide of a compound ra- 
dical, benzule. This mode of considering the molecular ar- 
rangement of the element corresponds admirably with its re- 
actions, and explains the remarkable stability of this sub- 
stance, under the influence of the most active agents. The 
hyduret of salicyle, on the contrary, undergoes considera- 
ble alterations with many substances, whence result new com- 
pounds, of a very definite composition, and connected by sim- 
ple relations with this hyduret. 
This hyduret does not combine directly with other bodies. 
Chlorine, bromine, and the metallic oxides, by their action up- 
on it, take away an equivalent of hydrogen, and an equivalent 
of chlorine, bromine, or metal, taking its place, is added to the 
other elements of the hyduret. There is consequently in the 
hyduret of salicyle an equivalent of hydrogen, which may be 
replaced by an equivalent of another body, and another part 
which always remains invariable, and which enters into nu- 
merous combinations. It is this latter which I regard as a 
compound radical, analogous to benzule, or rather to cyanogen, 
and which, to indicate its origin, I call salicyle. 
