RUMFORD, BENJAMIN COUNT (BENJAMIN THOMPSON). - THE MECHANICAL EQUIVALENT OF HEAT.

An Enquiry concerning the Nature of Heat, and the Mode of its Communication. Read february 2, 1804.

(London, W. Bulmer and Co., 1804). 4to. No wrappers as extracted from "Philosophical Transactions" 1804 - Part I. Pp. 77-182 and 2 engraved plates (showing his experimental apparatus). First and last leaves with some faint browning and brownspots. The plates with some browspots, mainly to margins. Wide-margined.

First appearance of Rumford's second large paper on the mechanical equivalent of heat, in which he owerthrows the caloric theory. Rumford's early papers were importent steps towards the conception of the principle of the "Conservation of Energy" and the thermodynamical laws.

"The importence of this investigation here entered into, - inasmuch as it applies to most of the operations of nature as well as art, - appears so manifest, that we shall not recapitulate what the author advances on the subject. before he proceeds to the details of his experiments for the purpose oof computing the emissions of heat from various bodies under a variety of circumstances, he finds it necessary to prmise a minute description of the principal part of the apparatus he contrived for the purpose..."(Abstract).

In his famous paper of 1798 "An Inquiry Concerning the Source of Heat Which is Exicited by Friction" showed that heat is a form of motion and not a substance as it was seen in the 18th century.
"He had been lead to the hypothesis that friction is an inexhaustable source of heat while considering the boring of a canon at Munich's military arsenal and had proceeded to experiment with brass guns at the arsenal. The experiments confirm the hypothesis, justifying his conclusion that heat is not a material substance as others had believed. He goeson to equate heat to motion."(Parkinson in "Breakthroughs" 1798 P.)

Order-nr.: 45131