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CHAPTER VIII. 

 The Constituents of Climate. 



WE have spoken of the steady average of the 

 climate at each place, of the difference of this 

 average at different places, and of the adaptation 

 of organized beings to this character in the laws 

 of the elements by which they are affected. But 

 this steadiness in the general effect of the elements, 

 is the result of an extremely complex and exten- 

 sive machinery. Climate, in its wider sense, is 

 not one single agent, but is the aggregate result 

 of a great number of different agents, governed by 

 different laws, producing effects of various kinds. 

 The steadiness of this compound agency is not the 

 steadiness of a permanent condition, like that of 

 a body at rest ; but it is the steadiness of a state 

 of constant change and movement, succession 

 and alternation, seeming accident and irregu- 

 larity. It is a perpetual repose, combined with a 

 perpetual motion ; and invariable average of most 

 variable quantities. Now, the manner in which 

 such a state of things is produced, deserves, we 

 conceive, a closer consideration. It may be useful 

 to show how the particular laws of the action of 

 each of the elements of climate are so adjusted 

 that they do not disturb this general constancy. 

 The principal constituents of climate are the 

 following : the temperature of the earth, of the 

 water, of the air : the distribution of the aqueous 



