Notices respecting New Books. 137 
“Caloric (for the reasonsadduced) is certainly contained in every 
body but the coldest, and, no one will hesitate to conclude from 
analogy, in that also. If then there be in all bodies an invisible 
imponderable fiuid or substance, capable of producing all the 
_phznomena of heat, it is surely unphilosophical to seek for any 
other cause of it, w here this exists.” The author therefore as- 
sumes that this mater is the only source of heat. He employs 
the name commonly used “calorie,” but ‘¢ without any intention 
to express an opinion that it isa simple substance.” —*¢ If caloric 
be matter, it possesses inertia; andc onsequently,w when once with- 
out taphion. unless acted on by some other body, it would re- 
main for ever at rest.’’—** The only powers by which matter 
unaided can act upon matter, are attraction and repulsion.”— 
Opposite powers in similar bodies where one is sufficient are re- 
jected in sound philosophy;—but we cheat ourselves with terms, 
What is *‘ radiation” but another name for  repulsion?’’+—“‘The 
law is universal, that all bodies attract caloric—but the degree in 
whick they attract it is different in different circumstances.”— 
<* That which has been called latent heat is only the effect of 
an increased exertion of the attraction for caloric, produced by 
the modifications of the attraction of cohesion.’ 
For the reasons stated by the author, “ caloric must necessarily. 
be imponderable.”—Though the passage of caloric is produced 
simply by attraction, the phanomena are modified by circum~. 
stances. ‘‘ Motion is given to caloric at its issuing from the 
heated body. But the attracting power continues tq operate on 
the caloric as it proceeds, and with a force increasing as it ap- 
proaches the attracting body; consequently the motion is con- 
tinually and increasingly accelerated. The ray strikes therefore 
upon the attracting hody, with a force greater than the then 
acting attraction, by the sum of the force of all the attraction 
preceding. Suppose the body attracting the caloric to be per= 
fectly hard and impenetrable, and the ray would rebound or 
be reflected; the then exerted attraction which alone would tend 
to continue it in contact, being so evidently less than the force 
of the attraction accumulated through its whole progress. Al- 
though no body is impenetrable to caloric, it is generally ad- 
mitted that the particles of every body are so. All the caloric 
therefore, whicl should not pass between the particles, but strike 
immediately on them, would be reflected as though it impinged. 
on a body perfectly hard and impenetrable. _ Accordingly, it is, 
found by experiment, that a very large portion of caloric is re- 
flected from some bodies to which it is attracted. Metals par- 
ticularly, attract caloric with considerable force, in proportion to 
their volume ; but when highly polished, a very small part is able 
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