SIGNIFICANT FEATURES OF MIGRATION 37 
seasonal variation to differ markedly from that characteristic of the 
pre-war period. 
Obviously it would be difficult to trace the response of migration 
to cyclical changes in industry without making allowance for the 
strong seasonal tendencies. Consequently, in most instances, the 
quarterly and monthly data on migration have been corrected for 
typical seasonal variation before they were used in comparisons 
with employment or other indices of business conditions. 
Heavy Emigration. 
Comprehensive data concerning emigration are available only 
for the period beginning on July 1, 1907. Prior to that date an ap- 
proximation of the volume of emigration is afforded by statistics of 
outgoing steerage passengers furnished to the Government officials 
by the courtesy of the steamship companies. Both the approx- 
imations available prior to 1907 and the subsequent more exact 
statistics indicate clearly that an adequate analysis of the effect of 
migration upon labor supply must rest upon emigration as well 
as immigration statistics. Is the volume of emigration large relative 
to immigration? Does the net movement (immigration less emi- 
gration) show a decided response to industrial prosperity or de- 
pression? Is there ever a net outgo? The answers to these questions 
should help us in our quest. Consequently, in Chapter V and 
succeeding chapters attention has been given to fluctuations in 
emigration as well as in immigration. Statistics of the proportion 
between immigration and emigration of selected races are given in 
a subsequent section of this chapter; and the estimated or recorded 
net movement in the fiscal years 1900 to 1924 inclusive, is given in 
Table 10 on page 50. In the years 1908 to 1924, in which direct 
statistics of departures are available, the volume of alien departures 
was equal to 51 per cent of the volume of arrivals, but the ratio of 
departures to arrivals varies widely in the several years. 
Preponderance of Males. 
Immigration to the United States has been preponderantly male 
in every year from 1820 to 1923, except the fiscal year of 1922, when 
the ratio of males fell to 48.4 per cent of the total immigration. 
Chart 3 portrays the percentage distribution by sexes throughout 
the entire period for which data are available. 
For the fiscal years 1820 to 1867, inclusive, this chart is based upon the distribution 
as estimated by the Immigration Commission in its Statistical Review of Immigration,