OF PHLOGISTON. 29 



2. The experiments on the revival of precipitate per 

 fe in inflammable air being differently reported by dif- 

 ferent experimenters, and being fometimes attended wath 

 hazard, 1 fhall add the following, which 'were made 

 feveral years ago, to thofe which 1 have made and re- 

 peated fince. 



In 9 ounce meafures of inflammable air from mallea- 

 ble iron and water I revived part of the precipitate fent ' 

 me by Mr. BerthoUet, which I had found to contain no 

 fixed air, till not more than one-fourth of the air re- 

 mained uaabforbed ; on examination, I found about one- 

 twentieth part of it fixed air; but mixing nitrous air 

 with it, it appeared that the air diflodged from the pre- 

 cipitate had not united with the inflammable air ; for the 

 flandard of equal meafures of them was 1.71. After 

 the procefs 1 miffed 1 8 grains of the precipitate. But 

 there are feveral caufes of lofs in this cafe, befides the 

 quantity of air expelled from the fubftance. 



In ^.^ ounce meafures of the fame inflammable air I 

 revived fome of the fame precipitate till it was reduced 

 to 0.77 ounce meafures. Of this one-lixth part was fix- 

 ed air, and the refiduum of the ftandard of 1.6. It ex- 

 ploded at once when the flame of a candle was prefented 

 to it. 



3. As pyrophorus imbibes pure air when it is expofed 

 to atmofpherical air, leaving nothing but phlogifficated 

 air, (in whicli it refembles a mixture of iron filings and 

 fulphur, which alfo makes a pyrophorus,) the fixed air 

 expelled from it afterwards mufi: have been formed by 

 the union of the pure air imbibed by it and the phlogif- 

 ton contained in itfelf. 



From- a quantity of old and fpoiled pyrophorus I got 

 1 80 ounce meafures of air, of the firft part of which 

 one half was fixed air, and the reft phlogifticated. At 

 the laft, the one half was fixed air, and the reft was 



inflam- 



