262 THE CHEMISTRY OF CREATION. 



It has been apparently forgotten, however, 

 that the air contains, in a condition highly 

 favourable to its activity, two principles of the 

 utmost energy in decomposition, the gas oxy- 

 gen and ozone. In all probability no such acci- 

 dental impurities can long exist in the gaseous 

 form mixed with the ordinary constituents of 

 the air. Even in water, which appears less 

 favourably circumstanced for such a result, a 

 natural process of purification takes place ; how 

 much more rapidly, then, in a medium consti- 

 tuted, like our atmosphere, of very large pro- 

 portions of an element which is ready for imme- 

 diate union, without having to be first set free 

 by a preliminary decomposition, and is furnished 

 also with a very easily decomposed substance 

 rich in oxygen in ozone, which is ever active 

 in fulfilling a similar office. There can be, in 

 fact, little doubt that the oxygen of the air and 

 that of ozone are sufficient to reduce all, or 

 almost all these occasional ingredients, by suc- 

 cessive steps, to simpler and simpler forms, 

 until at length they are deposited in a solid 

 state, and thus are removed from the thin folds 

 of our earth's mantle, or are converted into 

 beneficial constituents of the air. Bodies 

 which are impure have generally a tendency to 

 volatilize ; in so doing they become exposed to 

 oxygen, the great purifier, and become pure. 



