Calendar of Discovery and Invention

Abstract

August 21, 1843.—It was during the Cork meeting of the British Association in 1943 that Joule on Aug. 21 read to “an unwilling addience of six” his paper “On the Calorific Effects of Magneto Electricity and the Mechanical Equipment of Heat.” From the experiments described he attained the value of 838 ft.-lb. for the mechanical equivalent. In a post-script to this paper Joule said that he was satisfied “that tho groat agents of nature are by the Creator's fiat indestructible, and that whatever mechanical force is expended, an exact equivalent of heat is always obtained.”