618 On the Materiality of Caloric. 
absorption of caloric. Thus, when ether is 
converted into gas, on removing the pressure 
of the atmosphere, according to this hypothesis, 
the capacity of the ether is increased by its vola- 
tilization; and the change of form is prior to, 
and the cause of, the absorption of caloric. 
The order of events, then, in the volatilization 
of ether, is first an alteration of form; next a 
change of capacity; and lastly an absorption of 
caloric. On this hypothesis, ether may exist 
in the state of gas, without containing a greater 
absolute quantity of caloric, than in a liquid 
form. But such an interpretation of pheno- 
mena is directly contradictory to an established 
principle, admitted, even by those who prefer 
the doctrine of capacities, viz. that all bodies, 
during their conversion froma fluid to a vapo- 
rous state, absorb caloric. It is at variance, 
also, with observed facts: for if a thermometer 
be immersed in a portion of ether, confined 
under the receiver of an air pump, the temper. 
ature of the ether will be found to sink gra. 
dually, during the exhaustion of the air; and 
the evaporation becomes proportionally slower, 
till, at last, it is scarcely perceptible. We may, 
therefore, infer, that at a certain point of dimi- 
nished temperature, the volatilization of ether 
would entirely cease, if the supply of caloric, 
from surrounding bodies, could be completely 
