282 NATURE STUDY. 



which we can build by the process of apperception and 

 with the aid of imagination. 



Not until the boys and girls have studied carefully 

 the valley or the brook which they can see, can they 

 gain any fair understanding, or form a fairly clear 

 mental picture, of the larger valley about which they 

 must read, the valley of the Mohawk or Hudson or 

 Missouri. Only from an investigation of the way in 

 which the brook near their home is wearing its banks 

 and carrying away sediment, and is thus making its 

 valley, can they understand how similar but greater 

 valleys have been formed or are being changed. Only 

 by noting the character and distribution of the rocks 

 and soil of their homes can they hope to understand 

 in some measure the materials with which other parts 

 of the earth are covered, and on which the value of any 

 region to man largely depends. 



This observational study of our immediate physical 

 environment is not merely the best foundation for an 

 understanding of our larger physical environment, what 

 is included in physical geography, but it is almost 

 equally essential for an intelligent study of political ge- 

 ography. The character and rate of development and 

 present condition of man in different parts of the earth 

 have been greatly influenced or largely determined by 

 physical environment. The phenomenal growth and 

 the present condition of such cities as Chicago, Buffalo, 

 and Duluth are due mainly to their location and to 

 other physical conditions. 



Geography must be more than a study of a descrip- 



