BOOK OF NATURE LAID OPEN. 171 



Kiiions that arise from terrestrial bodies ascend into 

 the atmosphere. To this capacious alembic take 

 their flight, not only the aqueous vapours that pro- 

 ceed from the sea, the rivers, and moist places of the 

 earth, but the steam or smoke of things melted or 

 burnt; the perspiring fumes of whatever enjoys life; 

 and the effluvia they emit when deprived of it, and 

 in a state of putrescence. How then, it may be 

 asked, is this heterogeneous mass preserved from 

 corruption, and purified from its offensive qualities ? 

 For, if by respiration, flame, and putrefaction, air is 

 rendered unfit for the support of animal life, there 

 can be no doubt, as Dr. Paley observes, by the con- 

 stant operation of these corrupting principles, the 

 whole atmosphere, if there were no restoring causes, 

 would come at length to be deprived of its necessary 

 degree of purity. 



Among these causes the Doctor mentions vegeta- 

 tion, and agitation with water, both of which have 

 been proved by experiment to have the effect of at- 

 mospherical restoratives; for a sprig of mint, corked 

 up with a small portion of foul air, placed in the light, 

 renders it again capable of supporting life and flame ; 

 and the foulest air, shaken in a bottle with water, 

 for a sufficient length of time, recovers a great de- 

 gree of its purity. Here we see the salutary effects 

 of storms and tempests the yesty waves, which 

 confound the heaven and the sea, are doing the very 

 thing, but upon a larger scale, which was done in 

 the bottle. And, in as far as the lower regions are 

 concerned, these, on account of their wide extension, 



