Two were called less than one .... 16% of the times given.
"    "     "      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 aesthesiometer 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 aesthesiometer.  I made an aesthesiometer 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.  The result of this was that: 

Two were called less,  14 per cent.
"    "     "   equal, 36   "   "
"    "     " greater, 50   "   "

I then increased the distance of the two cards to 15 mm., the other conditions remaining the same, and found that: 

Two were called less,  11 per cent.
"    "     "   equal, 50   "   "
"    "     " greater, 39   "   "

It will be noticed that the ratio in this last series is not materially different from the ratio found when the two knobs of the aesthesiometer were compared with one knob.  The ratio found when the distance was 10 mm., however, is somewhat different.  At that distance two were called greater half of the time, while at 15 mm. two were called equal to one half of the time.  The explanation of the difference, I think, is found in the comments of one of my subjects.  I did not ask them to tell in what way one object was larger than the other—­whether longer or larger all around or what—­but simply to answer ‘equal,’ ‘greater,’ or ‘less.’  One subject, however, frequently added more to his answers.  He would often say ‘larger crosswise’ or ‘larger lengthwise’