81 



the plants will be deprived almos entirely 

 of their organs of respiration and trans- 

 piration. 



But besides this greater space for the 

 heads, as the roots follow the surface of 

 the earth, plants on the side of a hill have 

 a greater space for their roots than if 

 they had only the base of the hill side to 

 grow on. In reference to an entire hill 

 of a given base, this increase of surface 

 or space for the roots will be not only 

 directly as the height of the hill, but also 

 directly as the steepness of its sides. 

 Taking one side of a hill, if the side 

 forms an angle of forty-five degrees with 

 the horizon, its additional surface or space 

 for roots, as compared with its base, 

 will be as the diagonal is to the side of 

 a square. 



We are not to expect that trees drawn 

 up in the interior of sheltered plantations, 

 and transplanted to exposed situations, 

 will grow. If we could move a cube acre 



F 



