New York already looms up as one of the modern wonders, with a 

 reasonable prospect of becoming within twenty years the metropolis and 

 financial center of tlie world. The vision of a city of ten or twenty millio:i 

 Iieople appalls the imagination. The growth of the seaboard, Cleveland- 

 I'ittsburgh, and Chicago manufacturing districts sustains the prophecy of 

 H. G. Wells that there will ultimately be a continuous urban industrial 

 district, extending from Boston, New York, and Philadelphia to Chicago 

 and Ht. Louis, with vai'ious outliers along the Mississippi. 



For the general map of future economies or use of land, Fig. C, we are 

 indebted to Raphael Zon of the U. S. Forest Service. (Circular 159.) 



The question of future population is not only a fascinating subject of 

 speculation, but a serious practical problem of vital importance to all stu- 

 dents of the conservation of natural resources. It is not at all a question 

 of space. If all the people in the world could be herded in Texas, every 

 n»an, woman and child could have a domain 70 feet square, equal to an 

 ordinary city lot. Even in Illiode island they could stand in rows 4 feet 

 (> iiK'hes apart both ways. The population which any region can support 

 is fixed, according to Dr. McGee, not by land area or limitation of atmos- 

 pheric nitrogen, but l)y water sup])ly, a prf)i>osition sustained by a com- 

 parison of the rainfall and population maps, which might almost serve one 

 in place of the other. 



He calculates that the "duty of water" in relation to human popula- 

 tion is "the maintenance of one human life a year for each five acre feet 

 used effectively in agriculture." The annual rainfall of the United States 

 is five billion acre-feet; therefore the capacity of the United States for 

 population is limited to one billion, giving a density aix)ut half that of 

 Belgium, a figure which may be reachetl in less than three centuries. Sev- 

 eral statisticians, calculating from known rates of increase, place the popu- 

 lation of the United States in the year 2000 at 250 to 350 millions. 



Even more momentous than the questlo,!. How many? is the questioii 

 What shall we be? In 1830 the people of the United State and Canada 

 numbered about 14,000,000 and were, except the French on the lower St. 

 Uawrence, of almost pure British stock. Shortly after 1S30 immigration 

 began on a large scale, and with some fluctuation has increased until the 

 present, when in some years a million aliens land upon American shores. 

 The total number amounts to about 28,000,000, of which 90 i>er cent, have 

 come from Europe. Previous to 1890, 75 per cent, of them were Baltic 



[4—29034] 



