FOREWORD 
R. Macaulay had begun an elaborate investigation of bond yields 
and interest rates since 1859, which we hope will appear soon. Dr. 
Willard L. Thorp was making two collections of materials dealing 
with cyclical fluctuations—a collection, recently published, of 
business annals for 17 countries during periods ranging from 36 to 
136 years, and a collection of economic statistics which is well ad- 
vanced. Finally, the present writer had in hand a general treat- 
ise upon Business Cycles, the first volume of which will be submitted 
to the directors of the National Bureau within a few months. Since 
the “shortage and surplus of labor in its relations to immigration 
and emigration” is chiefly a problem of short-period oscillations, it 
was obviously relevant to the National Bureau's existing scheme of 
work. 
At our request, the University of Wisconsin granted leave of 
absence to Dr. Harry Jerome, Assistant Professor of Economics, in 
order that he might assume charge of the new undertaking, and later 
extended the leave. To the University, and particularly to its 
Department of Economies, our hearty thanks are due. Aided by 
a small corps of assistants and the advice of other members of the 
National Bureau's staff, Dr. Jerome analyzed the voluminous, yet 
incomplete, records of migration to and from the United States, and 
compared these records with various indices of business activity 
here and abroad. The present volume presents in concise form his 
conclusions concerning the short-period fluctuations in the demand 
for and supply of labor in the United States, and the role played by 
migration in these fluctuations. The National Bureau hopes that 
this carefully documented study of a problem too often treated in a 
controversial spirit will prove useful to all who are interested in mi- 
grations and to all who are interested in business cycles. 
Before Dr. Jerome had finished the present monograph, the 
Committee on Scientific Problems of Human Migration asked 
the National Bureau to undertake another investigation. This 
concerns the problem of “Migration and the Mechanization of In- 
dustry’—that is, the relation between the conditions on which 
relatively unskilled labor can be hired and the adoption of auto- 
matic machinery for the performance of work which may be done 
by hand. In May, 1924, the recently organized Social Science 
Research Council appointed a Committe on Human Migration, 
which included besides three members of the older Committee (Dr. 
Yerkes, Miss Van Kleeck, and Dr. Wissler), Dr. Edith Abbott,