_C_ (30) - 29.03 41.23 35.75
_D_ (20) - 30.87 34.07 17.24
_E_ (50) + 65.30 75.86 29.98
_F_ " + 50.74 50.74 5.89
_G_ " + 66.38 88.10 44.98
_H_ " + 65.40 80.76 42.93
_I_ " - 0.02 80.22 47.53
_K_ " - 44.60 52.56 32.93
_L_ " - 71.06 73.30 31.86
Average: - 3.38 62.88 32.17


The plane of vision in judgments made with the right eye alone is
deflected upward from the true horizon to a greater degree than it is
depressed below it in those made with binocular vision, the respective
values of the constant errors being -7'.70 and +11'.66, a difference
of 19'.36. When the field of vision is darkened except for the single
illuminated disc, a similar reversion of sign takes place in the
constant error. With binocular vision the plane of the subjective
horizon is deflected downward through 36'.62 of arc; with monocular
vision it is elevated 3'.38, a difference of 40'.00, or greater than
in the case of judgments made in the lighted room by 20'.64. This
increase is to be expected in consequence of the elimination of those
corrective criteria which the figured visual field presents. The two
eyes do not, of course, function separately in such a case, and the
difference in the two sets of results is undoubtedly due to the
influence of movements in the closed eye upon that which is open; or
rather, to the difference in binocular functioning caused by shutting
off the visual field from one eye. The former expression is justified
in so far as we conceive that the tendency of the closed eye to turn