118 ECONOMIC ESSAYS IN HONOR OF JOHN BATES CLARK
of the factors, (3) the degree to which the actual course of wages,
interest rates, and the proportions of the total product received
by the factors have conformed to what would be expected from
our analysis once the elasticities, etc., are known.
I have for overayear® been attempting to determine inductively
from English and American experience the probable nature of the
supply curve of labor and capital. The relationship between the
short-run supply of labor and the rate of real wages has been
tested as regards the proportions gainfully employed, the standard
 hours worked, the percentages of absenteeism, turnover, ete.
The interconnections between the movements of real wages and of
birth and net fertility rates have also been studied in great
detail, as have the relationships between real wages and the total
number of man hours offered for sale.
The supply curve of capital has also been explored by computing
 indexes of the growth of physical capital in both England
and the United States, and correlating these changes with changes
in the rate of interest.
Several other lines of investigation have also been started
and it is hoped that all of these inductive studies may soon be
published. It is not pretended, however, that more than a beginning
 can be made by any one man. A large group of inductive
workers is needed to secure the concrete values for the many
unknowns, and thus put content into what are at present, rather
empty economic boxes. If this article serves only to indicate
the nature of the problem, to analyze the forces at work, and to
stimulate others with the desire of adding concrete material for
the solution, it will have fulfilled its purpose.
1 Since the early part of 1925.

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