ose in a tranquil pool; but in the rapids a further
set of forces is also operative. In the work referred to, issued in
1899, an effort was made to isolate the phenomena of Economic Statics
and to attain the laws which govern them. Necessarily this study made
a certain impression of unreality, since it put out of sight changes
which are actually going on and are the conspicuous fact of modern
life. It assumed the conditions of a world without any such movement
and endeavored to formulate laws which, in such a condition, would fix
standards of value, wages, interest, etc. It put actual changes out of
sight, intentionally and heroically, but with a full recognition of
the fact that they are actually taking place and must in due time be
introduced and studied. We live in what is _par excellence_ an age of
progress, and it is in part for the sake of perceiving the laws of
progress that we first disentangle from them the laws of rest and make
a separate study of these. The world from which change is excluded is
unreal, but the _static laws_ which can be most clearly discerned by
mentally creating such a world have reality. Every day's transactions
are governed by them as truly as a physical element like water in
active movement is affected by forces which, if they acted alone,
would bring it to a state of permanent rest. The first purpose,
therefore, of the present work is to show the presence and dominance
in the real world of the forces described in the earlier work. It
brings static laws into view and endeavors to show how they act at
any one particular stage of industrial evolution. Even while changes
are examined, the fact is perceived that there are steadily at work
forces which, if changes should cease, would make society conform to a
certain imaginary static model and makes wages and interest also
conform to static standards.

Another purpose of the work is to examine seriatim the effects of
different changes, to gauge the probability of their continuance, and
to determine the resultant of all of them acting together. It is
important to know under what conditions changes proceed at a normal
rate, and when the standard of wages rises as it naturally should. As
the actual rate of wages pursues its rising standard, but lags
somewhat behind it, it is necessary to know what determines the
interval between the two, and when the interval is normal. What is
called "economic friction" is the cause of this interval and is an