THE 



POPULAR SCIENCE 



MONTHLY. 



JUNE, 1910 



SCIENTIFIC WOKK OF THE DEPAETMENT OF 



AGEICULTUEE 



Br W J McGEE, LL.D. 



NATIONAL CONSERVATION COMMISSIONER (SECRETARY SECTION OF WATERS) 



THE ancients saw in the four elements of earth, air, water and fire 

 the basis of being; moderns recognize earth, air, water and sun 

 as the prime requisites for individual and national existence. 



The earth is of three parts : the life and growth on the surface ; the 

 surface, which sustains life and growth; and the part beneath, which 

 sustains the surface with its life and growth. 



The air is of four aspects : it is an extension of the earth ; it yields 

 a part of the substance for life and growth on the surface; it is a 

 vehicle for movement of other things; and in its own movement it 

 affects the surface and influences life and growth. 



The water is of three forms, liquid, solid and gaseous, and performs 

 five functions: it is a part of the earth; it is jointly with the air an 

 extension of the earth ; it yields the chief part of the substance for life 

 and growth; it forms a vehicle for bodies and powers; and in its 

 proper movement it is an effective agency of process, including life 

 and growth. 



The sun possesses several powers : it holds the earth in its place ; it 

 fixes the succession of days and seasons; it controls the forms of water 

 and the movements of both water and air; it effectuates process, in- 

 cluding life and growth; it yields heat, light and actinity; and it 

 stores power on and beneath the surface in fuel to be released through 

 fire. 



The power and prosperity of men and nations are measured by 

 knowledge of and control over these natural elements — i. e. } human 

 life is, as it were, balanced against and paired with the elementary ma- 



vol. lxxvi. — 36. 



