62 THE WOOD. 



roots downwards in search of the nourishment 

 which, on account of their being sheltered from 

 rain, they could not find near the surface. If, as 

 it sometimes happens, a very violent storm uproots 

 the trees growing on the verge of a wood, the 

 consequences are as disastrous to those in the in- 

 terior as they would be to a besieged city, of which 

 the walls had been battered down. They are 

 snapped off or uprooted on all sides, encounter- 

 ing an assailant against whom they were not pre- 

 pared. The same results are to be apprehended 

 when the woodman imprudently cuts down the 

 timber which skirts a forest. This, I may remark, 

 is rarely done, for that which naturally serves as a 

 protection to a wood, is of the least use to man, 

 from its being short, while that which grows in 

 the interior is much more serviceable, from its 

 length and straightness. 



Rain, besides performing the important office 

 of supplying leaves with nourishment, keeps them 

 in a healthy state by washing them. Leaves, as I 

 have before hinted, are copiously furnished with 

 pores, through which they both inhale and exhale. 

 These pores are exceedingly small, and would, in 

 all probability, become choked by dust and the 

 work of insects, if the surface of the leaf were 

 not occasionally cleansed, a process which is most 

 effectually performed by the sprinkling of rain. 

 The air which we breathe, and that inhaled by 

 plants, though proceeding from the same source, 

 are very different in kind. That which is alone 

 calculated to support animal life is called oxygen, 

 and is one of the constituent parts of the atmos- 

 phere which surrounds us. Every time we take 

 breath we receive a portion of it into our frames, 



