384 On phlogiston. 



acquires no acidity, and gives out air more impure after 

 than before the procefs, nor is there any oxygen in what 

 remains of the metals. Where, then, is the oxygen into 

 which it is faid that the w^ater is refolved, at the lame tims 

 that it gives out hydrogen, or inflammable air? 



5. I have had abundant confirmation of the experiments 

 that I made with needles. I made ufe oi Jleel on the fup- 

 pofition that, abounding with phlogifton, it would part 

 with more than it would gain in proportion to other fub- 

 ftances ; and that the phlogifton it contained uniting v/ith 

 the pure air would make more phlogifticated air. 1 lately 

 heated 100 grains of the needles in 7.3 oz. meafurcs of at- 

 mol'pherical air, over mercury, till it was reduced to 6.5 oz. 

 mealures, without any fenfible quantity of fixed or inflam- 

 mable air in it, being wholly phlogifticated ; a diminution 

 fo much Icfs than ufual, that much phlogifticated air muft 

 have been formed in the procefs. As the needles had not 

 gained or loft any fenfible weight, fomething muft have 

 been thi^own off from them, though it could not be col- 

 lected ; and this could only kave been from fomething go- 

 ing out of them, and not by any thing entering into them. 



6. It is faid that when ted precipitate^ which is a calx 

 ot mercury, is heated in inflammable air, the pure air ex- 

 pelled from it uniting with the inflammable air, forms wa- 

 ter. But in my late experiments I have had the cleareft 

 proof that it does not form either water or any other fub- 

 ftance, but remains mixed with the remainder of the in- 

 flammable air, while it imbibes fome of the inflammable 

 air, and is revived by it. This appears from examining 

 the air that remains, and which is found to contain a por- 

 tion of pure air, and efpecially from the explojion of the 

 two kinds of air, which has more than once happened 

 to me, and is not a little dangerous. I find by computa- 

 tion, that fo much inflammable air is abforbed in the re- 

 vival of red precipitate, that an ounce of mercury will ab- 



forb 



