Caloric theory: Encyclopedia II - Caloric theory - Demise

Caloric theory - Demise

In 1798, Count Rumford published An Experimental Enquiry Concerning the Source of the Heat which is Excited by Friction, a report on his investigation of the heat produced while manufacturing cannons. He had found that boring a cannon repeatedly does not result in a loss of its ability to produce heat, and therefore no loss of caloric. This suggested that caloric could not be a conserved "substance" though the experimental uncertainties in his experiment were widely debated.

Rumford's experiment led to the work of James Prescott Joule and others in the 19th century, and a competing theory began to gain popularity, characterising heat as a kind of motion, the kinetic theory.

In 1850, Rudolf Clausius published a paper showing that the two theories were compatible, as long as the calorists' principle of the conservation of heat was replaced by a principle of conservation of energy. In this way, the caloric theory was absorbed into the annals of physics, to be replaced by modern thermodynamics, in which heat is the kinetic energy of molecules.

Adapted from the Wikipedia article "Demise", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki