306 Analyjis of the Afa. 



it moftly abforbed, but did fometimes gene- 

 rate, and then abforb again : And it was the 

 fame with oil of Vitriol, filings of Iron and 

 Water, and Newcaftle Coal, and compound 

 Aqua-fortis, and others : viz. At firft, when 

 the ferment was brisk, the abforbing fumes 

 role fiftefr, whereby more air was abforbed 

 than generated ; but as the ferment abated, to 

 fuch a degree as to be able ftill to generate 

 elaftick air, but not to fend forth a propor- 

 tionable quantity of fumes, in that cafe more 

 air would be generated than abforbed. 



And in Experiment 95. there are feveral 

 inftances of the air's being in like manner ab- 

 forbed in leffer degrees, by other fermenting 

 mixtures : As in the mixture of fpirit of Harts- 

 horn with filings of Iron, and with filings of 

 Copper : And fpirit of Sal Ammoniac with 

 filings of Copper ; and alfo filings of Iron 

 and Water ; powdered Flint, and compound 

 Aqua-fortis ; powdered Briftol Diamond with 

 the fame liquor. 



It is probable from Experiment 103 and 

 106. where it was found that the thicker 

 the fuliginous vapours were, the farter they 

 abforbed the air, that if the above-mentioned 

 fermenting mixtures had not been confined 



in ciofe veiTels, but in the open air, where 



the 



