& MIGRATION AND BUSINESS CYCLES 
iron fluctuates in close sympathy with the volume of industrial 
operations and is consequently considered a good barometer of 
industrial activity. Monthly estimates of pig iron production are 
not available until in the eighties, but annual production figures are 
given for the years beginning with 1854 and hence afford additional 
evidence concerning industrial conditions in the period during and 
following the Civil War. 
CHART 11 
CycLEs oF Pic Iron PropucTiON AND IMMIGRATION: 1860-1919. 
Unit= one standard deviation 
2.0% 
aki 
T 
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RoE Yori. py o— 
20} Beo-Gy ___WR-79 | BoD | [690-99 | joey [HAT 
sNumerical data in Tables 14 and 18. 
In Chart 11 we have a comparison of the cyclical fluctuations in 
annual pig iron production and total immigration from 1860 to 
1919. On close examination it will be seen that, aside from a few 
striking exceptions such as the marked fall in pig iron in 1865 and 
in the period of the Great War, the two series exhibit approximately 
the same succession of peaks and troughs, but that these do not 
always exactly coincide in time. This observation leads us to in- 
quire to what extent the fluctuations in immigration lag behind the 
fluctuations in industrial activity. 
The Lag. 
With only annual data it is impossible to make a close computation 
of the extent of such lag as may exist, but it is possible to determine 
4