CAVENDISH, HENRY. - WEIGHING THE WORLD - THE MOST IMPORTENT ADDITION TO GRAVITATION THEORY SINCE NEWTON.

Versuche über die Dichtigkeit der Erde zu Bestimmen. Erläutert vom Herausgegeber (Gilbert). (Experiments to determine the Density of the Earth.).

Halle, Rengerschen Buchhandlung, 1799. Without wrappers. In "Annalen der Physik. Herausgegeben von Ludwig Wilhelm Gilbert", Bd. 2, Erstes Stück. (The entire issue offered). Titlepage to vol. 2. Pp. 1-118 a. 2 folded engraved plates. Cavendish's paper: pp. 1-62. (the torsion balance of Michell shown on the plates).

First German edition of Cavendish's famous paper in which he calculated the weight of the earth and determined its mass. He also, as the first, observed gravitational motion of minute portions of matter. He estimates the earth's mass to 6,6 x 10 to the potential of 24 kg. The original paper "Experiments to determine the Density of the Earth" appeared in Philosophical Transaction, 1798.

"Cavendish published five papers between 1784 and 1809...With one exception they were comparatively minor productions....The exception was his determination of the density of the earth or weighing of the world in 1798, by means of John Michell's torsion balance. The apparatus consisted of two lead balls on either end of a suspended beam; these movable balls were attracted by a pair of stationary lead balls. Cavendish calculated the the force of attraction between the balls fro the observed period of oscillation of the balance and deduced the density of the earth from the force. He found it to be 5.48 times that of water. Cavendish was the first to observe gravitational motions induced by comparatively minute portions of ordinary matter...By weighing the world he rendered the law of gravitation complete. The law was no longer a proportionally statement but a quantitatively exact one; this was the most importent addition to the science of gravitation since Newton."(DSB III, p. 158.).

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