3C5 On thk doctrine 



inflammable. In another experiment of this kind I 

 found feven-tenths of the air fixed, and the reft inflam- 

 mable. 



The fixed air that is expelled from lime which has 

 been long expofed to the atmofphere cannot have any- 

 other origin than the pure air that it has imbibed and 

 fome phlogiflon which it derived from the fire ; for the 

 air to which it is expofed is always fomething lefs pure 

 than it was before. 



From 1 5 dwts. of fallen lime I got 45 ounce meafures 

 of fixed air, and 25 inflammable from the gun barrel in 

 which the experiment was made. Whether quicklime 

 has been expofed to the atmofphere, fo as to become 

 what is called fallen lime, or has been faturated with wa- 

 ter, they come in time to be of the fame weight, and to 

 have the fame properties ; the former continually gaining 

 weight, and the latter lofmg it. 



From 15 dwts. of lime faturated with water, and then 

 expofed to the atmofphere, I got ^^ ounce meafures of 

 fixed air. 



4. If any metal be calcined in common air over lime 

 water, a very thick fcum will be formed on its fur- 

 face, and much of the air will be imbibed by the calx 

 that is formed. I have recited the refult of this procefs 

 with feveral of the metals, and I fhall now obferve that 

 I had the fame refult with platina, filver, and gold. In 

 the experiment with platina t,t, ounce meafures of air 

 were reduced to 26^, of the ftandard of 1.75. 



5. That phlogifticated air is fometimes formed by the 

 union of dephlogifticated air and phlogifton is as clearly 

 proved by experiment as that fixed air is formed from 

 the fame elements. One proof of this is that common 

 air can never be diminifhed fo much by the pureft de- 

 phlogifticated air as it may be by nitrous air, the refidu- 

 um in both the cafes being alike phlogifticated air. I 



could 



