Vol. 6, 1920 
STATISTICS: PEARL AND REED 
285 
The upper asymptote given by (xviii) has the value 197,274,000 
roughly. This means that according to equation (xviii) the maximum 
population which continental United States, as now areally limited, will 
ever have will be roughly twice the present population. We fear that 
some will condemn at once the whole theory because the magnitude of 
this number is not sufficiently imposing. It is so easy, and most writers 
on population have been so prone, to extrapolate population by geometric 
series, or by a parabola or some such purely empirical curve, and arrive 
at stupendous figures, that calm consideration of real probabilities is most 
difficult to obtain. While, as will appear from the next section of this 
POPULATION OF UNITED STATES 
n&o leoo leio lezo /63o ibao iqso leco leio leeo lego tsoo isio 
YEAR 
FIG. 3 
Showing result of fitting equation (xviii) to population data. 
paper, we have no desire to defend the numerical results of this section, 
and indeed ourselves regard them only as a rough first approximation, 
it remains a fact that if anyone will soberly think of every city, every 
village, every town in this country having its present population multi- 
plied by 2, and will further think of twice as many persons on the land in 
agricultural pursuits, he will be bound, we think, to conclude that the 
country would be fairly densely populated. It would have about 66 
persons per square mile of land area. 
It will at once be pointed out that many European countries have a 
much greater density of population than 66 persons to the square mile. 
