190 Analyjis of the Air. 



above one third of their elafticity 5 after; 

 which the remainder was permanently ela- 

 ftical. In which ftate it has continued, 

 without any fenfible alteration, for thefe 

 fix years, that I have kept fome of the 

 air of calculus humanus by me. 



That the great quantities of air, which are 

 thus obtained from thefe feveral fubftances 

 by diftiilation, are true air, and not a mere 

 flatulent vapour, I was allured by the fol- 

 lowing Trials; viz* I filled a large receiver, 

 which contained 540 cubick inches, with air 

 of tartar; and when it was cool, Ifufpended 

 the receiver on the end of a balance while its 

 mouth was inverted in water. Then, upon 

 lifting the mouth of the receiver out of water, 

 I immediately covered it by tying a piece of 

 bladder over it. When I had found the ex- 

 acT: weight, 1 blew out all the air of tartar 

 ,with a pair of bellows which had a long ad- 

 ditional nofe that reached to the bottom of 

 the receiver. And then tying the bladder 

 on, I weighed it again, but could find no 

 difference in the fpecifick gravity of the two 

 airs ; and it was the fame with an air of 

 tartar, which was 10 days old. 



As to the other property of the air, elafti- 

 city, I found it exaclly the fame in the ait 



of 

 5 



