CHEMICAL FARMING 217 



this power in leaf is generated is not fully under- 

 stood, but it is estimated that far more horse power 

 is developed in all the leaves than that of the com- 

 bined power of all the motors and locomotives in 

 the world. So out of this food manufactured by the 

 plant, of air and water, with the tiny amount of 

 chemicals contained in the water, the plant can build 

 up a tree out of a twig, a mighty oak from an acorn, 

 bushels of wheat from a few seeds, tons of potatoes 

 from their "eyes" cut one "eye" to a piece or al- 

 most a ton of tomatoes grown in ten square feet of 

 space. 



The very special problem is how to feed the plant 

 that it may be enabled to utilize its power to pro- 

 duce sugar and starch given it by the sun. The sun 

 has the latent energy; if the leaf has the requisite 

 material, the result will be accomplished. 



Everything except the air taken in by the plant 

 must come to it through the root hairs, with more 

 than fifty thousand doors to the square inch of the 

 leaf through which the air is taken. The openings in 

 the root hairs are yet smaller too small to be visible 

 through the ultra microscope so the nourishment 

 taken in that way must be in solution to enable 

 it to enter them, showing why the soil must be moist 

 for the root hairs to absorb it. 



The next problem is that of the plant's require- 



