Analyjis of the Air. 305 



mixture, then inflead of abforbing 85 cubick 

 inches, as before, it generated 80 cubick 

 inches of air: So that fermenting mixtures, 

 which have fulphur in them, do not always 

 abforb, but fometimes ''generate air : The 

 reafon of which in the Experiment now under 

 confideration feems to be this, viz. in the firft 

 cafe a good quantity of elaftick air was gene- 

 rated by the inteftine motion of the ferment- 

 ing ingredients 5 but there ariiing thence a 

 thick, acid, fulphureous fume, this fume ab- 

 forbed a greater quantity of elaftick air than 

 was before generated : And we find by Expe- 

 riment 103, that the fulphureous particles 

 which fly off in the air, do by their attraction 

 deftroy its elafticity ; for in that Experiment 

 burning Brimftone greatly deftroyed the air'^ 

 elafticity ; which muft be done by the flame, 

 and afcending fumes ; becaufe in the burning 

 of any quantity of Brimftone the whole mafs 

 is in a manner wafted, there remaining only a 

 very little dry earth : And therefore the ab- 

 forbed air cannot remain there, but muft be 

 abforbed by the afcending fumes, which then 

 attract moft ftrongly, when reduced ad mi- 

 nima : And it is well known, that a Candle in 

 burning flies all off into flame and vapour, fo 

 that what air it abforbs, muft be by thole fumes. 



Expe- 



