ies 
J. LeConte on Binocular Vision. 165 
therefore various degrees of optic convergence, but always with 
the same result. There is, therefore, no rotation of my eyes 
when the plane of vision is inclined 45° downward. In con- 
tinuing the inclination still farther downward I observed a 
decided rotation of the eyes in the contrary direction, i. e., 
n 
nD 
., Inall these experiments, in order to detect the true rotation, 
1t is absolutely necessary that the median line of sight should, 
on that horizontal which passes through the small circle, for 
those above and below converge by perspective. 
* More recent experiments, just concluded, have convinced me that in my own 
°yes, if the se alte is very slight, the outward rotation does reach zero and 
may even be converted into an inward rotation, The reason is, that when my 
Mig are parallel or nearly so, elevation of the visual plane causes d ion. 
paru.ecione as stated by Meisener. In these 
the yes are parallel causes 
“ses, therefore, Meissner’s results on this point are entirely true. 
