OF PHLOGISTON. 



31 



could not by'any mixture of dephlogifticated and inflam- 

 mable air, fired by an eledlric ipark, reduce it to lefs than 

 2.5 ; whereas by nitrous air the fame dephlogifticated 

 air was diminiflied to 0.04 ; fo that there muft have been 

 a produdion of phlogifticated air when the inflammable 

 air was ufed. 



If after any diminutions of common air by phlogiftic 

 procefles more phlogifticated air is found in fome of them 

 than there is in others, the additional quantity muft have 

 been formed in the procefs ; and that there is a great va- 

 riety in thefe rcfults I have obferved before. 



Keating fine needles in common air over mercury till, 

 after its greateft diminution, it was incrcafed to its origi- 

 nal bulk, I found that it had nothing fenfibly inflamma- 

 ble in it, but was wholly phlogifticated ; whereas the ad- 

 dition of one-fourth of inflammable air to three-fourths 

 of phlogifticated air was eafily diftinguiftiable by the 

 flame of a candle. Fixed air will be produced in this 

 procefs if it be made over lime water, but not with cer- 

 tainty in any other circumftances. 



When fubftances that diminiili air, and leave it phlo- 

 gifticated, emit inflammable air before and after the pro- 

 cefs, it is reafonable to conclude that they did the fame 

 during the procefs ; and fince nothing inflammable is 

 found in the air after it, thatit united with the pure part 

 of the air to which it was expofed, and by that union 

 formed part of the phlogifticated air ; fo that lefs of this 

 kind of air exifted in the atmofphere than has generally 

 been fuppofed. This I have obferved to be the cafe with 

 a mixture of iron filings and fulphur. It was the fame 

 with iron that had been partially difl^blved in vitriolic 

 acid. After climinifliing a quantity of air 1 immerfed it 

 in mercury, and it gave out a fmall quantity of inflam- 

 mable air. 



I have 



