es, but a no less far-reaching
rhythmization of the labor in fine adaptation to the needs of the
psychophysical organism, long before the appearance of the machines.
The beginnings of the machine period frequently showed nothing but an
imitation of the rhythmical movements of man.[26] To be sure, the
later improvements of the machine have frequently destroyed that
original rhythm of man's movement, as the movement itself, especially
in the electric machines, has become so quick that the subjective
rhythmical experience has been lost. Moreover, the rhythmical
horizontal and vertical movements were for physical reasons usually
replaced by uniform circular movements. But even the most highly
developed machine demands human activity, for instance, for the
supplying with material; and this again has opened new possibilities
for the adjustment of technical mechanism to the economic demand for
rhythmical muscle activity. The growth of technical devices has thus
been constantly under the control of psychological demands, in spite
of the absence of systematic psychological investigations. But the
decisive factor was, indeed, that these psychological motives always
remained in the subconsciousness of civilization. The improvements
were consciously referred to the machine as such, however much the
practical success was really influenced by the degree of its
adjustment to the mental conditions of the workingmen. The new
movements of scientific management and of experimental psychology aim
toward bringing this adaptation consciously into the foreground and
toward testing and studying systematically what technical variations
can best suit the psychophysical status of man.

Those who are familiar with the achievements of scientific management
remember that by no means only the complicated procedures on a high
level are in question. The successes are often the most surprising
where the technique is old, and where it might have been imagined that
the experiences of many centuries would have secured through mere
common sense the most effective performance. The best-known case is
perhaps that of the masons, which one of the leaders of the scientific
management movement has studied in all its details.[27] The movements
of the builders and the tools which they use were examined with
scientific exactitude and slowly reshaped under the point of view of
psychology and physiology. The total result was that after the new
method 30 masons comple