" " " equal to .... 48% " "
" " " greater than .... 36% " "

Approximately half of the time two were called equal to one, and if
there had been no difference in the sensations half of the remaining
judgments should have been that two was smaller than one, but two were
called larger than one more than twice as many times as one was called
larger than two. There was such uniformity in the reports of the
different subjects that no one varied much from this average ratio.

This experiment seems to indicate a very slight power of
discrimination of stimulations within the threshold. In striking
contrast to this is the power to perceive variations of distance
between two points outside the threshold. To test this the
æsthesiometer was spread enough to bring the points outside the
threshold. The back of the hand was then stimulated with the two
points and then the distance varied slightly, the hand touched and the
subject asked to tell which time the points were farther apart. A
difference of 2 mm. was usually noticed, and one of from 3 to 5 mm.
was noticed always very clearly.

I wondered then what would be the result if small cards set parallel
to each other were used in place of the knobs of the æsthesiometer. I
made an æsthesiometer with cards 4 mm. long in place of knobs. These
cards could be set at any angle to each other. I set them at first 10
mm. apart and parallel to each other and asked the subjects to compare
the contact made by them with a contact by one card of the same size.
The point touched by the one card was always between the points
touched by the two cards, and the one card was put down so that its
edge would run in the same direction as the edges of the other cards.