THE PRE-WAR QUARTER CENTURY 5 
to represent the best estimate of the course of prices of those goods 
and services which constitute the bulk of clearings. Mr. Snyder 
has demonstrated that this curve may be interpreted as a measure 
of the volume of trade and ordinarily anticipates the fluctuation of 
production. 
This index does not differ materially from those for factory em- 
ployment and pig iron production, though the lag between its 
changes and those in migration is somewhat greater. The maximum 
correlation, judging from visual inspection, is obtained when a lag 
of about four months is assigned to immigration. 
SHORT-PERIOD IMMIGRATION AND EMIGRATION STUDIES 
The Period from 1892 to 1902, inclusive. 
This period was marked by a prolonged depression, with a tem- 
porary recovery in 1895, followed toward the end of the decade by 
the beginning of an era of industrial expansion, accompanied by 
rising immigration. Aside from the growth movement, which has 
been approximately eliminated by the device of expressing the data 
as deviations from an eighty-four month moving average, the fea- 
tures just mentioned may be observed by reference to Chart 13 on 
page 92. 
We have previously noted the approximate similarity in the 
general contour of the immigration and the factory employment 
curves. While immigration evidences a slump in the latter part of 
1892 and early in 1893 which is not shown on the employment 
curve, it quickly recovers and reaches a high point in 1893 about 
two months after the employment curve reaches its crest. Both 
show clearly the decline in 1893 and the subsequent depression. 
Both recover in 1895 and decline again in 1896, but the migration 
decline begins about five months later than the employment de- 
cline and continues for about five months later. Both series ex- 
perience a long rise beginning in 1898. 
The Depression of 1893-1894. 
Because of the relatively scant data upon which comparisons of 
industrial activity and immigration are based in the nineties, too 
much importance should not be attached to conclusions reached by 
a study of this period until they are substantiated by reference to 
the more complete information available in later years. However, 
the depression of 1893-94 affords an opportunity to illustrate and 
compare various available methods of analysis and presentation. 
Gr