J. LeConte on Binocular Vision. 319 
ly ; (b) that all objects (different objects) lying in the 
visual lines, whether on this side or beyond the point of sight, 
have two of their images (one of each) superposed ; so that the 
two visual lines under all circumstances are combined to form a 
binocular visual line passing from the combined eyes, through 
the point of sight, and onward to infinite distance. 
uet us now, in the light of these facts, examine M. Pictet’s 
experiments. I will pass over for the present what he seems to 
his crucial experiments, and take up first the general 
phenomena of double images, as a proper understanding of the 
nature of these will make all that follows clear. 
sees 
the wall behind it by means of an illusive image propagated 
from the right eye. Now owr explanation is entirely different ; 
and we cannot but think that the —— double images 
Mage nothing from the left eye, and therefore the parts covered 
by these images must be seen, by the corresponding eye, by 
ltt 
