UNDERGROUND CLIMATE. 131 



roots of plants, although they burrow beneath the 

 surface, are not on that account msensible to the 

 influences which are felt by the stem and branches 

 above. On the contrary, they are fully as sensitive, 

 or even more so. If leaves and flowers wither be- 

 neath the scorching air, so do roots when the earth 

 around them becomes parched ; if the verdant 

 foliage rejoices in the rain-drop, not less is it grate- 

 ful to the earth-bound root ; if cold paralyzes the 

 blossom, and compels the foliage to shrink and 

 perish, roots also are affected in like manner. On 

 the other 'hand, that warmth which causes the 

 blossom to unfold and the leaf to open its bosom to 

 the gentle breath of spring, acts equally upon the 

 root, exciting it to growth, and putting in action 

 all the sucking force by which the leaves and flow- 

 ers are nourished. Nor is the access of air less 

 important to one than to the other ; both extremi- 

 ties of plants feed on air, — the roots even more than 

 the leaves. Place a plant where the air can gain 

 no access to its leaves, and they fall off, and are 

 followed by the decay of the stem. Roots, if en- 

 tirely deprived of air, will gradually shrink and die. 

 Hence it is that the condition of the air in the 

 ground, the temperature and moisture of the soil 

 itself, require to be regulated, as well as that of the 

 atmosphere which rests upon it ; and thus the im- 

 portance of regulating properly underground climate 

 becomes evident." 



