114 



POPULAR SCIENCE MONTHLY. 



Population in the United States, and Increase in each Census Period of the 



Nineteenth Century. 



Thus it is quite plain that something has happened in the United 

 States to diminish the rate of increase of population after 1860. Up 

 to that time the growth in each census period from 1800 downwards 

 had ranged between 33 and 36 per cent. Since then the highest rates 

 have been 30 per cent, between 1870 and 1880 and 25 per cent: between 

 1880 and 1890. There is a suspicion, moreover, that, owing to errors 

 in the census of 1870, which were corrected in 1880, the increase be- 

 tween 1870 and 1880 was not quite so high as stated. There is accord- 

 ingly a somewhat steep decline from a growth in each ten years prior to 

 1860, ranging between 33 and 36 per cent., to a growth first of about 

 25 per cent., and finally of 21 per cent. only. The Civil War of the 

 early sixties naturally occurs to one as the explanation of the 

 break immediately after 1860, but the effects could hardly have 

 continued to the present time, and a more general explanation is sug- 

 gested. 



Other special explanations have occurred to me as partly account- 

 ing for the change. One is that, prior to 1860, the United States at 

 different times increased its territory and population partly by purchase 

 and partly by annexation. But I cannot make out that either the pur- 

 chase of Louisiana early in the century, or the subsequent annexations 

 following the Mexican war, would make a material difference. There 

 is a considerable increase certainly after the Mexican war, but it would 

 be difficult indeed to estimate how much of the population of Texas 

 and New Mexico, which was then added to the Union, had previously 

 swarmed over from the Union, and had thus been from the first 

 economically, if not politically, part of the United States. Another 

 obvious suggestion is that possibly immigration into the United States 



* This does not include population of Indian reservation, etc., now in- 

 cluded in the ofl5cial census for the first time. 



