Cavendish, HENRY

Cavendish, HENRY, natural philosopher, eldest son of Lord Charles Cavendish, and a grandson of the second Duke of Devonshire, was born at Nice, October 10, 1731. From a school at Hackney he passed in 1749 to Peterhouse, Cambridge, but quitted it three years later without a degree; thereafter he devoted the whole of his long life to scientific investigations, a large fortune bequeathed him by an uncle enabling him to follow uninterrupted his favourite pursuits. A silent, solitary man, he hated so to meet strangers, that he had his library—a magnificent one—in London, four miles from his residence on Clapham Common, so that he might not encounter persons coming to consult it; whilst his female domestics had orders to keep out of his sight, on pain of dismissal. His dinner he ordered daily by a note placed on the hall-table. He died, unmarried, at Clapham, 10th March 1810, leaving more than a million sterling to his relatives. As a philosopher, Cavendish is entitled to the highest rank. To him it may almost be said we owe the foundation of pneumatic chemistry, for prior to his time it had hardly an existence. In 1760 he discovered the extreme levity of inflammable air, now known as hydrogen gas—a discovery which led to balloon experiments and projects for aerial navigation; and later, he ascertained that water resulted from the union of two gases—a discovery which has erroneously been claimed for Watt (q.v.; see also WATER). The famous Cavendish Experiment was an ingenious device for estimating the density of the Earth (q.v.). The accuracy and completeness of Cavendish's processes are remarkable. So high an authority as Sir Humphry Davy declared that they 'were all of a finished nature, and though many of them were performed in the very infancy of chemical science, yet their accuracy and their beauty have remained unimpaired.' Cavendish also wrote on astronomical instruments; and his Electrical Researches (1771-81) were edited by Professor Clerk Maxwell (1879). See his Life by G. Wilson, forming vol. i. of the Cavendish Society's Works (1846).