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at Abbe Fontana's). When this 

 very acid is joined to fome earthy 

 fubftance, or to a vegetable alkaline 

 fait (with which it conflitutes nitre), 

 it yields by the action of the fire 

 nothing but pure dephlogifticated 

 air, in fuch abundance, that the 

 quantity of it is equal to about 

 eight hundred times the bulk of 

 the nitre, as Abbe Fontana found. 



Such-like tranfmutations which 

 air feems to undergo are every 

 where obvious in nature. All bo- 

 dies upon our earth, or almoft all 2 

 undergo continually fome alterati- 

 ons, and at lart deviate entirely from 

 what they were before. The plant 

 which affords us the moil whole- 

 fome food is perhaps the next to 

 another which draws out of the 

 fame fpot of ground a poifonous 

 juice. The food by which a viper 



lives 



