from that in the other. No difference was found, and in work
thereafter each subject was allowed the preparatory interval which
made the conditions subjectively most satisfactory to him.

Ample time for rest was allowed the subject after each test in a
series, two (sometimes three) series of twenty to twenty-four tests
being all that were usually taken in the course of the hour. Attention
to the interval was not especially fatiguing and was sustained without
difficulty after a few trials.

Further details will be treated as they come up in the consideration
of the work by groups, into which the experiment naturally falls.


II. EXPERIMENTAL RESULTS.


1. The first group of experiments was undertaken to find the direction
of the constant error for the 5.0 sec. standard, the extent to which
different subjects agree and the effects of practice. The tests were
therefore made with three taps of equal intensity on a single dermal
area. The subject sat in a comfortable position before a table upon
which his arm rested. His hand lay palm down on a felt cushion and the
tapping instrument was adjusted immediately over it, in position to
stimulate a spot on the back of the finger, just above the nail. A few
tests were given on the first finger and a few on the second
alternately throughout the experiments, in order to avoid the numbing
effect of continual tapping on one spot. The records for each of the
two fingers were however kept separately and showed no disagreement.