Chap, i.] M. Lavoijier. 



pleafing inftance of well-directed afliduity. But one 

 of the mod (Inking difcoveries of this phiJofbpher is, 

 that the nitrous air, which he procured from the fo- 

 lution of certain metals in the nitrous acid, had the pro- 

 perty of diminifhing a quantity of the pureft part of the 

 common air, the remainder being by this procefs ren- 

 dered noxious and unfit for combuftion j and upon 

 this principle nitrous air was for a long time received 

 as a teftofthe purity of the atmofphere, though it will 

 afterwards appear that this tell is imperfect. Dr. 

 Prieftley alfo purfued the laft mentioned experiment 

 of Mr. Cavendifh, and found that a fimple acid, or 

 alkali, might be made to affume the form of a per- 

 manently elaftic fluid; and thefe fluids he diftinguifhed 

 by the title of acid and alkaline airs. But to fpecify 

 all Dr. Prieftley's difcoveries, even in this very con- 

 cife manner, would greatly exceed my limits ; I muft 

 therefore be content with only curforily mentioning the 

 moft remarkable. 



The publication of thefe experiments of the Englifh 

 philofophers excired the attention of feveral ingenious 

 foreigners; but the only difcoveries worthy of notice 

 in this place are thofe of M. Lavoifier. The experi- 

 ments of this philofopher, afcertaining the precife quan- 

 tity of water and elaftic fluid, which are contained in 

 flaked lime and mild alkali, alfo thofe upon the burn- 

 ing of.pholphorus, are the neateft and mod complete 

 that have ever been -publifhed. The only new <3if- 

 covery of any note, which we can attribute to him, 

 was, demonftrating that the calcination of metals is 

 owing to the abforption of a certain elaftic fluid ; but 

 he did not at firft perceive that this fluid was in any 

 refpect different from the fixable air produced by effer- 

 vefcing mixtures. In a memoir, however, which he 

 read after the publication of his elTays, before the 



French. 



