252 LAVOISIER. 



While M. Lavoisier was employed in generalizing the 

 phenomena observed by others, in correcting former 

 opinions, and in adding materially to the store of facts 

 by his own experiments, but rather filling up blanks 

 left by his predecessors than producing any very striking 

 novelties himself, two most important discoveries were 

 made in England which call for our careful observation, 

 the composition of water and of the nitrous acid. 

 Respecting the latter discovery there is no question 

 whatever. Mr. Cavendish alone is its author. Dr. 

 Priestley had shewn that nitrous acid was resolvable 

 into nitrous gas, which he discovered, and oxygen. 

 M. Lavoisier had never gone further than to suppose 

 that gas the base of the acid. He had never sus- 

 pected it to be compounded of any other known mate- 

 rials, except in so far as it plainly contained oxygen ; 

 and as for azote, the residue of atmospheric air after the 

 oxygen gas, or respirable part, is withdrawn from it, we 

 find him expressing strongly ('Mem./ 1777,) that this 

 is a body of whose nature we are wholly ignorant. I 

 am not aware that he ever laid any claim whatever to 

 share in Mr. Cavendish's great discovery, to which he was 

 led by the most philosophical consideration of the acid 

 always found when oxygen gas, impure from the pre- 

 sence of nitrogen or azote, is burnt with inflammable air. 

 A careful course of experiments devised and directed by 

 him, performed by his colleagues of the Royal Society, 

 led to the knowledge of this important truth. 



But the other great discovery with which his name is 

 inseparably connected stands in different circumstances. 

 Nothing can interfere with his title to be regarded as 

 having first made the capital experiment upon which it 



