4 6 



SOILS 



manufacture : none but green plants, and by them only 

 in the sunlight, can carbon be used or starch or sugar 

 manufactured by the leaves. Thus we find that sunlight 



CARBONIC ACID 



CARBONIC ACID 



THE UNDERSIDE OF A LEAF WITH A MICROSCOPE 

 a. Mouths or stomata; b. Cells of the leaf 



is power or energy and the green coloring of leaves the 

 machine that combine in the performance of this work. 



Soil-food is secured by roots. Before soil-food can 

 be used by any plant it first must be put in soluble form 

 by the water of the soil. It then reaches the plant by 

 means of root hairs the small, slender, delicate branches 

 of the roots. These root hairs are the feeding organs, and 



