3 1 o Analyfis of the Air. 



in proportion to the fulphureoufnefs and 

 thicknefs of thofe fumes. 



I have alfo fhewn in many of the fore* 

 going Experiments, that plenty of true per- 

 manent elaftick air is generated from the 

 fermenting mixtures of acid and alkaline fub- 

 ftances, and especially from the fermenta- 

 tion and diffolution of animal and vegeta- 

 ble bodies : Into whofe fubftances we fee it 

 is in a great proportion intimately and firmly 

 incorporated 5 and confequently, great quan- 

 tities of elaftick air muft be continually ex- 

 pended in their produ&ion, part of which 

 does we fee refume its elaftick quality, when 

 briskly thrown off from thofe bodies by fer- 

 mentation, in the diflblution of their texture. 

 But part may probably never regain its elaf- 

 ticity, or at leaft not in many centuries, that 

 efpecially which is incorporated into the 

 more durable parts of animals and ve- 

 getables. However we may with pleafure 

 fee what immenfe treafures of this noble 

 and important element, endued with a 

 moft aftive principle, the all- wife Providence 

 of the great Author of nature has provided j 

 the conftant wafte of it being abundantly 

 fupplyed by heat and fermentation from in- 

 numerable 



