fF 213 j 
at Abbé Fontana’s). When this 
very acid is joined to fome earthy 
fubftance, or to a vegetable alkaline 
falt (with which it conftitutes nitre), 
it yields by the action of the fire 
nothing but pure dephlogitticated 
air, in fuch abundance, that the 
| apap sty of. it is equal to about 
“hundred 
he nitre, as s Abbé Fontana found. 
| Merch Lhe tranfmutations which 
air feems to undergo are every 
where obvious in nature. All bo- 
dies upon our earth, or almoft all, 
undergo continually fome alterati- 
ons, and at laft deviate entirely from 
what they were before. The plant 
which affords us the moft whole- 
fome food is perhaps the next to 
another which draws out of the 
fame {pot of ground a poifonous 
juice. The food by which a viper 
lives 
