of EdinhuTgli, Session 1883-84. 
435 
viie “ interaxial distance.” This, indeed, was my purpose in trying 
it. With parallel axes, moreover, the position of the false images 
should be unaffected by making the paper approach or recede, for 
accommodation is still negative, and the left eye looking at a distant 
object. In reality, however, if the distance of the paper be either 
increased or diminished, the two central false images separate in 
proportion. A piece of red glass held in front of the right hole 
e c d f 
Fig. 2. 
e cd f 
® # S 
Fig. 3. 
/ 
d 
Fig. 4. 
e d f 
e ® o 
0 
c 
Fig. 5, 
fe d f 
® ® O 
o 
c 
Fig. 6. 
colours the right lateral image and one of the median ones, and 
shows that when the paper is made to recede, the red image travels 
to the right of the other, as in fig. 5, and when it is made to approach 
the red one travels to the left, as in fig, 6. From this it is clear 
that the visual axes are convergent. It may be objected that the 
9 
VOL. XII. 
F 
