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I could judge, it was ftill as inflammable as ever. 

 Another quantity of inflammable air was alio redu- 

 ced in the fame proportion, by a moufe putrefying 

 in it ; but its inflammability was not ieemingly 

 leffened. 



Air diminifhed by this mixture of iron filings and 

 brimftone, is exceedingly noxious to animals, and 

 I have not perceived that it grows any better by 

 keeping in water. The fmell of it is very pun- 

 gent and offenfive. 



The quantity of this mixture which I made ufe of 

 in the preceding experiments, was from two to four 

 ounce meafures ; but I did not perceive, but that 

 the diminution of the quantity of air (which was 

 generally about twenty ounce meafures) was as great 

 with the fmalleft, as with the largeft quantity. How 

 fmall a quantity is necefTary to diminim a given 

 quantity of air to a maximum, I have made no ex- 

 periments to af certain. 



As foon as this mixture of iron filings, with brim- 

 ftone and water, begins to ferment, it alfo turns black, 

 and begins to fwell, and it continues to do fo, till it 

 occupies twice as much fpace as it did at firft ; and 

 the force with which it expands is great; but how 

 great it is I have not endeavoured to determine. 



When this mixture is immerfed in water, it gene- 

 rates no air, though it becomes black, and fwells. 



Vol. LXIL E e VI', Qf 



