XIV 

 HENRY CAVENDISH 



1731-1810 



Henry Cavendish, the discoverer of hydrogen, was horn of English 

 parents in Nice, October 10, 1/31. He studied at Cambridge Uni- 

 versity, England, and in lydo joined the Royal Society, devoting his 

 great fortune to the advancement of science. He discovered hydro- 

 gen in iy66, and later, using Priestley's discovery of oxygen, found 

 that the two gases combined under certain physical conditions to pro- 

 duce water. Besides his studies in chemistry, he made some interest- 

 ing discoveries in physics. In lyS^ he proposed the theory that heat 

 zvas a motion rather than a substance; and in i/q8 he computed the 

 density of the earth to be about five and a half times that of water. 

 He died at Clapham, February 24, 18 10. 



THE COMBINATION OF HYDROGEN AND OXYGEN INTO 



WATER * 



In Dr. Priestley's last volume of experiments is related an experi- 

 ment of Mr. Warltire's, in which it is said that, on firing a mixture of 

 common and inflammable air by electricity in a close copper vessel 

 holding about three pints, a loss of weight was always perceived, on 

 an average about two grains, though the vessel was stopped in such a 

 manner that no air could escape by the explosion. It is also related, 

 that on repeating the experiment in glass vessels, the inside of the 

 glass, though clean and dry before, immediately became dewy ; which 

 confirmed an opinion he had long entertained, that common air 

 deposits its moisture by phlogistication. As the latter experiment 

 seemed likely to throw great light on the subject I had in view, I 

 thought it well worth examining more closely. The first experiment 

 also, if there was no mistake in it, would be very extraordinary and 



* From Experiments with Airs — Transactions of Royal Society of London 



(1784). 



102 



