1 94 Jnalyfis of the Air. 



and abforbed by animal, vegetable and mine- 

 ral fubftances. 



That this air confifts of particles which are 

 in a very active ftate, repelling each other 

 with force, and thereby conftituting the fame 

 kind of elaftick fluid with common air, is 

 plain from its raifing the Mercury in Expe- 

 riment 88 and 89, and from its continuing 

 in that elaftick ftate for many months and 

 years, tho' cool'd by fevere frofts ; whereas 

 watry vapours, tho* they expand much with 

 heat, yet are found immediately to condenfe 

 into their firft dimenfions when cold. 



The air generated by fire was not, in many 

 inftances, feparated without great violence 

 from the fix'd bodies, in which it was incor- 

 porated ; as in the cafe of Nitre, Tartar, Sal 

 Tartar and Copperas ; whence it mould leem, 

 that the air generated from thefe Salts, may 

 probably be very inftrumental in the union 

 ot Sq!:s, as well as that central, denfer, and 

 compacter particle of earth, which Sir IJaac 

 Newton obferves, does by its attraction make 

 the watry acid flow round it, for compoiing 

 the particles of Salt, qu. 3 1. For fince, upon 

 thedifiblution of the condiment parts of Salt 

 by fire, it is found, that upon feparating and 



.ciiizing the acid fpirir, the air-particles do 



in 



