604 On the Materiality of Caloric. 
to examine, whether J have been anticipated by 
any of the authors, whose essays have been 
published, during the two last years, 
A Review of some Experiments, which have. been 
supposed to disprove the Materiality of Heat. 
It has long been a question among philoso- © 
phers, whether the sensation of heat, and the 
class of phenomena arising from the same cause, 
be produced by a peculiar kind of matter, or 
by motion of the particles of bodies in general. 
The former of these opinions, though far’ from 
being universally admitted, is now most generally 
received ; and the peculiar body, to. which the 
phenomena of heat are referred, has been deno- 
minated by M. Lavoisier, caloric, Against 
the doctrine of the French school, some forcible 
arguments have lately been advanced by Count 
Rumford and by Mr. Davy, both of whom have 
adopted that theory respecting heat, which as- 
signs, as its cause, a motion among the particles 
of bodies. 
The method of reasoning, employed by Mr. 
Davy, in proving the immateriality of the cause 
of heat, is the reductio ad absurdum, i. e. the 
oppugned theory is assumed. as true, together 
with its applications; and facts are, adduced, 
directly coatradictory of the assumed principles, 
