Zeitbewusstseins,' III., _Phil. Studien,_ XII., S. 195-204.

The limitation of time intervals by tactual stimulations offers,
however, a rich field of variations, which promise assistance in the
analytical problem of the psychology of time. The variations may be
those of locality, area, intensity, rigidity, form, consecutiveness,
and so on, in addition to the old comparisons of filled and empty
intervals, intervals of varying length, and intervals separated by a
pause and those not so separated.

To begin with, we have selected the conditions which are mechanically
the simplest, namely, the comparison of two empty time intervals, both
given objectively with no pause between them. We have employed the
most easily accessible dermal areas, namely, that of the fingers of
one or both hands, and introduced the mechanically simplest
variations, namely, in locality stimulated and intensity of
stimulation.

It was known from the results of nearly all who have studied the time
sense experimentally, that there is in general a constant error of
over- or underestimation of time intervals of moderate length, and
from the results of Meumann,[3] that variations in intensity of
limiting stimulation influenced the estimation decidedly, but
apparently according to no exact law. The problem first at hand was
then to see if variations introduced in tactual stimulations produce
any regularity of effect, and if they throw any new light on the
phenomena of the constant error.

[3] Meumaun, E.: 'Beiträge zur Psychologie des Zeitsinns,' II.,
_Phil. Studien_, IX., S. 264.