i he ee ti a 
: Bn : al . *' . 
ee ee We B. Rogers on Binocular Vision. 
¢ ; 
@* 
9 
have the same mutual inclination in each ease as that of AM and 
BN, although of greater length in proportion to their greater fe 
tance from Rand L. Lastly, suppose the axes to be steai 
converged though some other corresponding points of the com- 
ponent lines so as for example to meet at O, we shall then have 
. » 
4 
4 
r, 
a 
- 
in plagg of AM BN a resultant consisting of the two intersecting — 
lines am bn patgllel to the former and lying in a parallel plane. 
corresponding attitudes in reference to D. ; 
It can hardly be doubted that the variable and seemingly ca- 
pricious phenomena just described are dependant on the succes- 
sive convergence of the axes to different distances, and on the 
perception resulting from this of a greater or less perspectiveness 
in the direction of the series of resultant points. ay be as- 
sumed that a certain degree of rapidity in effecting this succes- 
sion of combinations, in other words, this successive intersection 
of the two lines at differents points of their length and at differ- 
ent distances from the eyes, is necessary to create a distinct and 
strong perception of relief. For as we have seen, every pat 
in this movement of the axes is accompanied by a reduction 
of the relief, and if continued destroys it altogether. Now 
as the progressive change of convergence of the optic axes in — 
these experiments has the effect of carrying the intersection of 
‘dis 
& 
