4^8 STUDIES OF NATURE. 



the objeds of Nature, for the reafon which I hate 

 already fuggefted, from our own moll craving ne- 

 ceffity ; but this very charadler appears foreign to 

 it : for it owes it's fluidity only to the adlion of the 

 heat j if you deprive it of this, it changes into 

 ice. It would be v&ry fingular, fhould it be made 

 to appear, after all our fundamental definitions, 

 that the natural (late of water was to be folid, and 

 that the natural ftate of earth was to be fluid : 

 now this muft adtually be the cafe, if water owes 

 it*s fluidity only to heat, and if earth is nothing 

 but an aggregation of fands united by different 

 glues, and attrafted to a common centre, by the 

 general adlion of gravity. 



The elementary qualities of air, are not of more 

 eafy determination. Air, we fay, is an elaftic 

 body : when it is fhut up in the grains of gun- 

 powder, the adlion of fire dilates it to fuch a de- 

 gree, as to communicate to it the power of hurling 

 a globe of iron to a prodigious diftance. But how 

 could it have been, with all this elafticity, com- 

 prefTed into the grains of a crumbling powder ? 

 If you put even any liquid fubftance into a ftate 

 of fermentation in a flafk, a thoufand times more 

 air will be feparated from it, than you could force 

 into the veflel without breaking it. How could 

 this air be confined in a fubftance foft and fluid, 

 without difengaging itfelf by its own adion ? 



The 



