2pt Analyfa of the Air. 



means of fire and fermentation raifedfrom^ 

 and abforbed by animal, vegetable and mi- 

 neral fubftances. 



That this air confifts of particles which are 

 in a very aftive ftate, repelling each other 

 with force, and thereby conftituting the fame 

 kind of elaftick fluid with common air, is 

 plain from its railing the Mercury in Expe- 

 riment 8 8 and 89, and from its continu- 

 ing in that elaftick ftate for many months, 

 tho' cooled by fevere frofts 5 whereas watry 

 vapours, tho' they expand much with heat, 

 yet are found immediately to condenfe in- 

 to their firft dimenfions when cold. 



The air generated by fire was not, in 

 many inftances, feparated without great vio- 

 lence from the fix'd bodies, in which it 

 Was incorporated ; as in the cafe of Nitre, 

 Tartar, SalTartar and Copperas: whence it 

 fhould feem, that the air generated from 

 thefe Salts, may probably be very inftru- 

 mental in the union of Salts, as well as that 

 central, denfer and compa&er particle of 

 earth, which, Sir Ifaac Newton obferves, 

 does by its attra&ion make the watry acid 

 flow round it, for compofing the particles of 

 Salt. qu. 31. for fmce upon the diffolution 



of 



