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Henry Cavendish (1731-1810) "His place in British natural philosophy is as the first after Newton to possess mathematical and experimental talents at all comparable to Newton's. In intellectual stature Cavendish was without peer in Eighteenth-century British natural philosophy" (DSB). |
| The
Discovery of Hydrogen, 1766:
"It appears from this experiment, that the air produced from sugar by fermentation, as well as discharged from marble by solution in acids, consists of substances of different nature" --page 179. |
The
Famous Cavendish Experiment, 1798: "By weighing the world, Cavendish rendered the law of gravitation complete... This was the most important addition to the science of gravitation since Newton" (DSB). A remarkable copy in original wrappers |
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| "In 1766 Cavendish published his first paper, for
which he received the Royal Society's Copley Medal. It was on
`factitious' airs, that is, airs that are contained inelastically in
other bodies but are capable of being freed and made elastic.
Cavendish's careful gravimetric discrimination of several factitious
airs, together with the work of Black on fixed air, put forward strong
evidence against the notion of a single, universal air" (DSB).
"Cavendish showed that hydrogen, which was then called `inflammable air' or `phlogiston,' was distinct from other combustible gases by measuring its density and the amount of gas evolved from a given amount of acid and metal... Early experimenters, had obtained the gas, but Cavendish was the first to study it carefully and report on its properties, so he is usually given the credit for having discovered it" (Britannica, Asimov). |
In 1798, Cavendish, by means of a torsion balance, was
able to measure the force of gravitational attraction between pairs of
lead spheres, thus allowing for the calculation of the gravitational
constant, G, in Newton's revolutionary law of universal gravitation.
With this value, the density of the Earth, and therefore the Earth's
mass, could readily be derived.
The experiment was beautiful in its simplicity. "The apparatus consisted of two lead balls on either end of a suspended beam; these moveable balls were attracted by a pair of stationary lead balls. Cavendish calculated the force of attraction between the balls from the observed period of oscillation of the balance and deduced the density of the Earth from the force. Cavendish was the first to observe gravitational motions induced by comparatively minute portions of ordinary matter. The attractions that he measured were unprecedentedly small, being only 1/500,000,000 times as great as the weight of bodies" (DSB). |
More images:
CAVENDISH, Henry. "Three Papers, containing Experiments on factitious Air," pp. 141-184 in Philosophical Transactions, Volume LVI for the year 1766 (the complete volume). London: L. Davis and C. Reymers, printers to the Royal Society, 1767. Small quarto, 20th-century leather library binding with embossed stamp of Boyce Thompson Institute for Plant Research on general title-page, two bookplates, and library pocket on rear pastedown. First printing. Light dampstaining, mostly marginal. Illustrated with numerous folding copper-engraved plates including large folding plate of Cavendish's experiments. |
More images:
CAVENDISH, Henry. "Experiments to determine the Density of the Earth," pp. 469-526 in Philosophical Transactions of the Royal Society of London for the year 1798, Part II (the complete volume). London: Peter Elmsly, printer to the Royal Society, 1798. Quarto, original paper wrappers with paper label, uncut. Housed in custom cloth clamshell box. First printing. An absolutely remarkable copy in original wrappers, illustrated throughout with folding engraved plates including two for the Cavendish experiment. Some foxing and dampstaining throughout; Cavendish article fine with foxing only to plates. As fine a copy as one can ever hope to obtain. Rare. |
Some notes on the life of Henry Cavendish.