ESTIMATING FUTURE POPULATION 



97 



prepared by the engineer, Mr. H. F. Snow (see Fig. 20). Here 

 all cities in the United States reaching a population of 27,000 

 between 1851 and 1870 were plotted, together with the past 

 records of Brockton, whose population in 1890 was 27,294. 



The growth of all these other cities being plotted (some 

 extending for 40 years), and making due allowance for natural 

 advantages possessed by some cities and not by Brockton, and 

 giving due weight to the municipalities existing under the same 



POPULATION CURVE 



drawn for 

 BROCKTON, MASS. 



1850 



FfllRi 



LJSC 



rmi 



- F >rtl 



qto 



rrfo 



nd 



d C 



Me. 



50000 



n i 



00000 



50000 



1900 

 FIG. 20. 



1940 



conditions as nearly as could be, the probable future population 

 of Brockton was obtained. 



The actual growth of this city has been more than was 

 expected, so that the discrepancy is greater in this case between 

 the prediction and the reality than in any of the other cities 

 noted. Thus the diagram indicates in 1900 and 1910, popula- 

 tions of 39,000 and 47,000, while the census gives values of 

 40,063 and 56,878. 



Rafter and Baker in a discussion of this subject give some 

 tables taken from Census Bulletin No. 52, showing the increase 



