Chap. II.] Chemical Philosophi/, lui 



gaseous form ; he discovered the power of vegeta- 

 tion to restore vitiated air*; he ascertained the 

 influence of light in enabling vegetables to yield 

 pure air ; and elucidated both the principles of 

 respiration, and the influence of oxygenous air 

 on the blood. But the great extent and value 

 of his inquiries, respecting the analyses of tlie at- 

 mosphere, and the production of various factitious 

 airs, can be fully understood only by the perusal of 

 his instructive volumes on these subjects. 



To the list of successive luminaries in chemistry, 

 now under review, it would be improper not to 

 add the name of M. Macquer, who contributed 

 in an eminent degree to the advancement of che- 

 mical knowledge by his excellent works, long held 

 in the highest esteem in every part of Europe. 

 His ingenious experiments and numerous discove- 

 ries, particularly respecting arsenic^ dyes, and earths^ 

 will ever entitle him to honour and gratitude from 

 philosophers. By the labours of these great men, 

 and of many others — whose names might vvith pro- 

 priety be mentioned, did not our limits forbid such 

 an enlargement of the list — the boundaries of che- 

 mical philosophy had been more extended, and its 

 stores of experiment and discovery more enriched, 

 within the twenty years immediately preceding the 

 introduction of the theory of the French academi- 

 cians, than in any whole century before. 



But some of the discoveries made bj' these aud 

 other chemists must be more particularly detailed, 

 in order to present the reader with a tolerable 



* See Additional Notes — (T), 



