2 ANALYSIS OF 



But in every cafe of the diminution of atmofpherical 

 air in which this is the refult, there appears to me to be 

 fomething emitted from the fubftance, which the anti- 

 phlogiftians fuppofe to a£t by limple abforption, and 

 therefore that it is more probable that there is fome fub- 

 ftance, and the fame that has been called phlogifton, or the 

 prificiple of itiJJammabilify (being common to all bodies 

 capable of combuftion, and transferable from any one of 

 them to any other) emitted, and that this phlogifton 

 uniting with part of the dephlogifticated air forms with 

 it part of the phloglfticated air which is found after the 

 procefs ; and in fome cafes there is more of this, and in 

 others lefs. Alfo, in fome cafes fixed air is the refult of 

 the union of the fame conftituent principles. 



A mixture of iron filings and fulphur, which, with a 

 little water, has been commonly made ufe of to diminifh 

 and phlogifticate air, and probably many other fubftances 

 which produce the fame effedt, if they be continued in 

 the air after tne diminution has advanced to its maxmiim, 

 occafion an increafe of the quantity, by an addition of 

 inflammable air. This mixture I find to have the fame 

 effedt when it is long confined in nitrous air, or in fixed 

 air ; and therefore it is probable that the fame would be 

 the cafe if it were confined in any other kind of air, or 

 in vacuo. It therefore, fecms natural to infer that the 

 fame principle which conftitutes inflammable air was from 

 the firft exhaling from the mixture, but that it did not 

 adually form inflammable air till there was no m.ore 

 dephlogiflicated air for it to unite with, and thereby 

 form phlogiilicated air. The experiments from which 

 this conclufion is drawn are recited in my former pub- 

 lications, and I have lately repeated them with particular 

 attention, and the fame refult. I have alfo lately obfer- 

 ved that by heating bones made black by burning without 

 accefs of air, in atmofpherical air, there is, after the 



period 



