Chap. II.] Chanical Piiilosophy. 105 



opinion, gave it the name of aerial acid. Mr. 

 Bewly called it mephitic acid, because it could not 

 be respired without occasioning death. Mr. Keir 

 called it calcareous acid; and, at last, M. Lavoi- 

 sier, after discovering that it is formed by the com- 

 bination of carbon and oxygen^ gave it the name of 

 carbonic acid gas, which it now generally bears *. 



The discovery oi inflammable hydrogenous air, in 

 1766, deserves also to be recorded as a remarkable 

 event. This air was obtained by Dr. Mayow, and 

 afterwards by Dr. Hales, from various substances, 

 and had been known, long before, in mines, under 

 the name of ih^ Jire damp. But Mr. Henry Caven- 

 dish ought to be considered as its real discoverer ; 

 since it was he who, in the year above-mentioned, 

 first examined it, pointed out the difference be- 

 tween it and atmospheric air, and ascertained the 

 greatest number of its properties f. It was found 

 by M. Lavoisier to be twelve times as light as 

 common air. Its nonrespirable character was 

 more fully determined by Scheele, Fontana, and 

 Davy. The products resulting from the combina- 

 tion of hydrogen with the sulphuric, phosplwric, 

 and ca?'bonic acids, were discovered and investigat- 

 ed principally by Scheele, Bergman, Fourcro}-, 

 Vauquelin, Gengembre, Kirwan, and Volta. It 

 was first called Hydrogen by the French academi- 

 cians, because it enters into the composition of 

 wafer. 



A short time after the discovery of Mr. Caven- 



* Thomson's Chemistry. In some sentences the autlior hnf 

 borrowed not only the facts, but also the language of thi'^ respect- 

 able writer. 

 ' f Pidlosophioul Transactions for I'^QQ. 



