ESTIMATING FUTURE POPULATION 



101 



of growth of American cities of the class under consideration, 

 and will give the general percentages found in the sixth column 

 of Kuichling's table. No such curve was drawn for the growth 

 in 1900-1910, as the points plotted were so irregular as to show 

 rather the lack of any general law than the evidence of the law 

 itself. Kuichling makes the diagram give a method of esti- 

 mating a future population as follows: Take from the diagram 



10,000 



50,000 



100,000 

 Population 



FIG. 22. 



150,000 



200000 



or table the rate of increase corresponding to the present popula 

 tion, interpolating if necessary; add that increase to the present 

 population; take the rate for that sum; find the increase cor- 

 responding; add the latter to the former sum, and continue 

 this for as many years as desired. The method is rather tedious 

 and gives only the general and probable law, with a result 

 which must be modified by such conditions as the previous 

 rate of growth, locality, facilities for manufacture, and trade 

 would suggest. 



