MIGRATION AND BUSINESS CYCLES 
ANNUAL STATISTICS OF INDUSTRIAL CONDITIONS 
To obtain a picture of the major features of changes in employ- 
ment conditions, let us first turn our attention to the fluctuations in 
various series of annual data which serve as more or less satisfactory 
indicators of conditions in the several industries in which immi- 
grants find employment. 
For this purpose we have used the following series: for factory 
employment, an index of estimated average number employed, 
1890 to 1922; for coal mining, the number of tons of anthracite and 
bituminous coal, respectively, produced each year from 1870 to 
1922: for construction, the annual increase in the operated mileage 
of railroads from 1891 to 1916 and an index of the estimated annual 
total value of construction from 1902 to 1920; for railway main- 
tenance, the average number of trackmen employed from 1889 to 
1914; and for general industrial and business conditions, several 
series, including the value of imports of merchandise 1870 to 1923, 
pig iron production 1870 to 1923, the clearings index computed by 
the Federal Reserve Bank of New York for 1876 to 1923, wholesale 
prices 1870 to 1922, and Professor E. E. Day’s index of manufacture 
1899 to 1923. 
For convenience in comparison, these series have been charted in 
two groups, on pages 59 and 62, one group consisting of those series 
which refer to calendar years (Tables 12-A and 12-B and Chart 6); 
and the other group, those series which refer to fiscal years ending 
June 30th (Tables 13-A and 13-B and Chart 7). 
The Calendar Year Group. 
The annual production of pig iron, bituminous coal, and anthra- 
cite coal, respectively, an index of the physical volume of manu- 
facturing, an index of the estimated total value of construction, 
the number of railway trackmen employed, and an index of whole- 
sale prices comprise the calendar year group. Pig iron is discussed 
more fully at subsequent points in this chapter. A few words 
concerning the reason for choice of some of the other series are 
pertinent. 
Railway Employment. 
Large numbers of immigrants are employed in the maintenance 
of railway track and roadbeds, and, consequently, we have included 
in our evidences of employment conditions a curve showing the 
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