Heinrich Hertz, ca 1878-1880

HERTZ, Heinrich (1857-1894). Autograph manuscript, “Research to Establish an Upper Limit for the Kinetic Energy of Electric Current," n.p., ca 1878-1880.

80 pages, 328 x 208mm, with seven pages of auxiliary text, with hand-drawn diagrams and graphs (pinholes and occasional small tears along left margin not affecting text, occasional light soiling from fingerprints).

The original manuscript for Hertz's first published scientific work—his first major experiment investigating the kinetic energy and mass of electricity—with significant portions of unpublished text. Performed in 1878, before the electron was discovered, Hertz's experiment necessitated that the mass and kinetic energy of electricity be indirectly deduced, and he was required to discount the effect of inertia on the flow of electrical current in a circuit. Hertz devised accordingly a technique to measure and compare the increased current generated by different self-inductive circuits – thus enabling Hertz to isolate the inertial contribution to the current and to assign an upper limit to the density of mass per unit charge. Undertaken while Hertz was still only a second-year physics student, this experiment yet aptly displays Hertz’s distinctive experimental genius, exhibiting both his capacity for conceiving new experimental techniques and his talent for constructing the often-novel apparatus required; and very notably, we already see here Hertz’s characteristic utilization of rectangular circuits and self-induction calculations, which would figure so prominently in his later work with electric waves.

Hertz explored intensively electromagnetism in a series of experiments over the course of a decade – beginning with this initial foray, and culminating in his 1888 discovery and production of electromagnetic radio waves. Hertz’s experiments validated Maxwell’s equations and demonstrated that electromagnetic waves traveled at the speed of light. (They also uncovered the photoelectric effect some 20 years before Einstein.) In his 1894 preface to Hertz’s seminal book on Mechanics, Wilhelm Helmholtz (Hertz’s mentor, and the party who suggested this present experiment to Hertz) stressed "the importance for Hertz’s future work of his early recognition of the quasi absence of inertial effects in the motion of electricity: 'These experiments clearly impressed upon his [Hertz’s] mind the exceeding mobility of electricity, and pointed out to him the way towards his most important discoveries.'" (Salvo D’Agostino, “Hertz’s Experiments on Electromagnetic Waves” in A History of the Ideas of Theoretical Physics: Essays on the Nineteenth and Twentieth Century Physics. Dordrecht: Kluwer Academic Publishers, 2000, 137).

Hertz’s experiments were of the greatest practical and theoretical consequence—essentially launching our modern age of electricity and telecommunications, and paving the way both for Einstein’s Theory of Relativity and for the quantum theory of the photon. Hertz’s brilliant career was cut short by his premature death at the age of 36. Autograph manuscripts or letters relating to his scientific work are very rare.

This lot is 80 pages, not 70 pages, as previously described.