THE FIRST ANNOUNCEMENT OF JOULE'S LAW, ONE OF THE FUNDAMENTAL LAWS OF ELECTRICITY

JOULE, James Prescott. On the Heat Evolved by Metallic Conductors of Electricity, and in the Cells of a Battery during Electrolysis, In Philosophical Magazine, Vol. 19, No. 124 (October), pp. 260-277. London: Richard and John E. Taylor, 1841. Octavo, contemporary blue paper wrappers. $4500.

First edition of the description of Joule's Law, one of the fundamental laws of electricity, "the first of the great laws with which Joule's name is imperishably connected" (DNB).

Joule, at only 22 years of age, established one of the most fundamental laws of electricity, Joule's Law, stating that "when a current of voltaic electricity is propagated along a metallic conductor, the heat evolved in a given time is proportional to the resistance of the conductor multiplied by the square of the electric intensity" (page 264). Joule's discovery of the universality of the conversion between electrical and thermal energy, a landmark in itself, led directly to the dramatically important law of the conservation of all energy. "These experiments contained the germs of Joule' second great discovery, the equivalence of heat and energy, which he fully developed later. But he had already made it clear that the energy set free in the battery is also proportional to the resistance of the circuit and to the square of the current" (DNB). Joule had originally announced his experimental results in a speech before the Royal Society on December 17, 1840, but the Royal Society did not deem the paper worthy of inclusion in its chief periodical publication, Philosophical Transactions; only an abstract appeared in Proceedings of the Royal Society. This is the first appearance in print of Joule's full paper. Also included in this volume is a paper by the young Charles Darwin, "On a Remarkable Bar of Sandstone off Pernabuco," an early Darwin publication resulting from his observations during the cruise of the Beagle. This issue has been bound with the entire Volume 19 of the Philosophical Magazine, covering the second half of 1841.

Interior fine, wear and soiling to wrappers. A desirable copy.