172 HARNESSING THE EARTHWORM 



Sun power drives the weather mill that grinds soil and pro- 

 pels still-secret processes by which in soil, sea, leaf, and flesh, our 

 common ingredients sun, air, water and a sprinkling of earthy 

 minerals combine into all forms of life and energy, including 

 man. 



Our power age is a governed explosion of buried sun power. 

 When coal, petroleum, and gasoline are burned, they deliver en- 

 ergy the sun stored in plants aeons ago. Farmers plowing, 

 miners digging, Sundays motorists out for an airing, airplane 

 drivers streaking for Europe or South America all are develop- 

 ing in their various persons and from their subject beast or 

 equipage, sun power previously fixed for use through a film of 

 soil ... 



Now for the transition from the poetical statement of the 

 abstract generalization to the more prosaic practical application 

 and analysis of the concrete facts : 



The dominant color of the earth what we might justifiably 

 call the color of life is green. Life endures because the earth 

 is green, the color-evidence of the existence of a substance which 

 has been called the most important material in the world : chloro- 

 phyll, leaf-green. Practically all the green substances of the plant 

 world are so closely related chemically that they may, for prac- 

 tical purposes, be designated as leaf-green or chlorophyll. The 

 sun, acting upon the chlorophyll in the leaf of plants through 

 the process known as "photosynthesis," produces sugar within 

 the plant. And sugar is the beginning of life, the chemical start 

 and nucleus around which the more complex compounds of pro- 

 toplasm are formed. For a brief and masterly discussion of the 

 meaning of chlorophyll, we refer the reader to a chapter in The 

 Green Earth, by Harold William Rickett, under the heading of 

 "The Green Color of Plants and What Comes of It." As one 

 simple illustration, the sunlight, acting upon the chlorophyll in 

 5 square inches of potato leaf will produce about 1 gram of 

 sugar per month. Quoting from The Green Earth, "... A 

 man may use, in the same time (1 month), the sugar made by 

 30,000 such leaves. He may not, indeed, eat so much sugar; but 

 all the food in his potatoes and in all the other comestibles which 



