s of the different points, I made a
brief preliminary series of experiments to determine in a general way
the influence of pressure on judgments of point distances. Only three
distances were employed, four, six and twelve centimeters, and three
weights, twelve, twenty and forty grams. Table III. shows that, for
three men who were to serve as subjects in the main experiments that
are to follow, an increase in the weight of the points was almost
always accompanied by an increase in the apparent distance.

TABLE III.

Distances. 4 cm. 6 cm. 12 cm.

Weights
(Grams). 12 20 40 12 20 40 12 20 40

R. 3.9 3.2 3.0 6.2 5.6 5.3 11.4 10.4 9.3
F. 4.3 4.0 3.6 6.1 5.3 5.5 12.3 11.6 10.8
B. 4.1 3.6 3.1 6.0 5.7 5.8 12.0 10.2 9.4
P. 4.3 4.1 3.7 5.9 5.6 5.6 13.1 11.9 10.7

In the standard distances the points were each weighted to 6
grams. The first three figures signify that a two-point
distance of 4 cm., each point weighing 6 grams, was judged
equal to 3.9 cm. when each point weighed 12 grams. 3.2 cm.
when each point weighed 20 grams, etc. Each figure is the
average of five judgments.

Now the application of this principle in my criticism of Parrish's
experiments, and as anticipating the direction which the following
experiments will take, is this: if we take a block such as Parrish
used, with only two points in it, and weight it with forty grams in
applying it to the skin, it is plain that each point will receive one
half of the whole pressure, or twenty grams. But if we put a pressure
of forty grams upon a block of eight points, each point will receive
only one eighth of the forty, or five grams. Thus, in the case of the
filled space, the end points, which play the most important part in
the judgment of the distance, have each only five grams' pressure,
while the points in the open space have each twenty grams. We should,
therefore, naturally expect that the open space would be
overestimated, because of the decided increase of pressure at these
significant points. Parrish should have subjected the blocks, not to
the same pressure, but to a pressure proportional to the number of
points in each block. With my apparatus, I was easily able to prove
the correctness of my position here. It will be seen in Tables IV. to
VIII. that, when the sum of the weights of the