TABLE I.

4 cm.               6 cm.               8 cm. 
Filled.   Open.        Filled.   Open.        Filled.   Open.

F.   5.3     4.7         7.8     7.6          9.3     10.5
F.   5.7     4.4         6.5     7.3          9.2     11.7
F.   6.0     5.6         8.2     7.3          8.7     10.8
—–­     —–­         —–­     —–­          —–­     ——­
Av.  5.7     4.9         7.5     7.4          9.1     11.0

R.   5.7     5.1         6.7     6.8          9.3     10.2
R.   5.4     5.4         7.2     7.1          8.5     10.7
R.   4.6     4.2         8.1     8.1          9.1     11.4
—–­     —–­         —–­     —–­          —–­     ——­
Av.  5.2     4.9         7.3     7.3          9.0     10.8

K.   5.6     5.1         6.8     6.7          8.1      9.6
K.   5.0     5.1         7.3     7.5          8.2     11.2
K.   4.9     4.9         8.2     8.1         10.1     10.1
—–­     —–­         —–­     —–­         ——­     ——­
Av.  5.2     5.0         7.4     7.4          8.8     10.3

TABLE II.

4 cm.               6 cm.               8 cm. 
Filled.   Open.        Filled.   Open.        Filled.   Open.

F.   5.1     5.0         8.0     8.3          9.2     10.3
F.   5.8     4.7         7.2     7.9          8.7     10.9
F.   5.6     5.5         6.9     9.1          9.1     11.1
—–­     —–­         —–­     —–­          —–­     ——­
Av.  5.5     5.1         7.4     8.4          9.0     10.8

R.   6.0     4.8         8.2     7.5          9.4     10.6
R.   5.7     5.4         6.5     7.4         10.1      9.4
R.   5.0     5.2         7.7     7.8          8.6     11.2
—–­     —–­         —–­     —–­         ——­     ——­
Av.  5.6     5.1         7.5     7.6          9.4     10.4

K.   4.8     4.8         8.2     8.3          8.1      9.8
K.   5.1     5.3         7.1     7.7         10.0     10.8
K.   4.7     5.0         8.1     8.6          8.6      9.4
—–­     —–­         —–­     —–­         ——­     ——­
Av.  4.9     5.0         7.8     8.2          8.9     10.0

The first two numbers in the first line signify that when an open distance of 4 cm. was taken, an adjacent open distance of 4.7 cm. was judged equal; but when the adjacent space was filled, 5.3 cm. was judged equal.  Each number in the column of filled distances represents an average of five judgments.  All of the contacts in Table I. were made simultaneously; in Table II. they were made successively.

In the next series of experiments the illusion was approached from an entirely different point of view.  The two points representing the open space were given on one arm, and the filled space on a symmetrical part of the other arm.  I was now able to use a much wider range of distances, and made many variations in the weights of the points and the number that were taken for the filled distance.