THE AIR AND THE SOIL. 377 



World, it is, at the same time, the great ven- 

 tilating process, by the instrumentality of which 

 the atmosphere of the teeming tropics, and less 

 fertile regions of the north, is properly inter- 

 mingled and purified. 



It has been well said, it is " the earth- 

 girdling atmosphere which makes the whole 

 world kin." The air we inhale with pleasure 

 as it breathes fresh over these heath-clad fields 

 and hills, but a little while since bade farewell 

 to the splendid vegetation of Brazil, or to the 

 palm-trees of Ceylon ; and it will leave us to 

 be wafted among the forests of India, or the 

 spice groves of the islands of the east. How 

 strange the thought! the gases gently rising, 

 discoloured with smoke, from yonder cottage 

 chimney, may soon become food to the vegetable 

 inhabitants of warmer regions than our own 

 may become appropriated by the sugar-cane, or 

 sago-palm, or become part of the tea-shrub, and 

 may actually return to us in the form of sugar, 

 sago, or tea ! 



The atmosphere is connected with the well- 

 being of vegetation in a remarkable manner also 

 by its influence on the soil. When land has been 

 exhausted by successive crops, the remedy has 

 been to let it lie " fallow," or, in other words, 

 rest from bearing crops for a little time. The 

 recovery of its lost ingredients is effected by the 



