48 On air heated 



In order to- vary the circumflanccs of thie experiment, 

 I heated clean filings of copper, and alfo bits of filver, 

 in inflammable air, by means of a burning lens ; and 

 tlie refult was fimilar, viz. a converfion of the inflam- 

 mable into phlogifticated air, for not only was the quan- 

 tity of air diminilhed, but the remainder was much lefs 

 in{l:\mmable than before. Atter heating hlings of copper 

 in 14 ounce meafures of inflammable air, till it was re- 

 duced to "1 ounce meafures, I fired a quantity of it to- 

 gether with a quantity of dcphlogifticated air, when the 

 diminution was to o.yy ; though when the fame dephlo- 

 gifticated air was exploded together with the fame quan- 

 tity of the original inflammable air the diminution w^as 

 to 0.62. The lame procefs being repeated with the re- 

 mainder of the inflammable air till it was reduced to 3-|- 

 ounce meafures, the diminution, when fired with the 

 liime quantity of dcphlogifticated air, was only to 

 1.25. When fmall bits of filver were heated in the fame 

 manner in inflammable air, the refult was the fame, viz. 

 a diminution both of its quantity and its inflamma- 

 bility. 



In the following experiments phlogifticated air was 

 produced from atmolpherical, dephlogiilicated, and ni- 

 trous, air. 



Three ounce meafures of atmofpherical air expofed a 

 whole day to a red heat in a copper tube were reduced 

 to 2-§-, completely phlogifticated ; which is in the propor- 

 tion of 91.6 of phlogifticated air in 100. Confequent- 

 ]y, there muft have been a produdtion of phlogifticated 

 air in the procefs. 



Two ounce meafures of dcphlogifticated air, of the 

 ftandard of 0.64, heated three or four hours in a caft 

 copper tube were reduced to fomething lefs than 2 

 ounce meafures, wholly phlogifticated. And 4 ounce 

 meafures of the fame dcphlogifticated air were in half 



a day 



