162 S. Rowley on Vision. 
distance of A, the axes be fixed upon the images of the pin at — 
B, then the image of the pin at A, seen by the left eye, and — 
that of a pin placed nearly 1,°, inch directly to the right of A, 
seen by the right eye, will be found lying in the same perpen- — 
dicular of no variation, the latter beyond the former, the dix 
tance between the two images being less than in the first cas. — 
In experimenting with this instrument, the position of the 
image of the pin at B seen by the left eye in a surface at : 
angles to the optic axis of that eye is visibly realized. For — 
when the axes are fixed toward A (as in the first instance) the — 
image of the transverse piece seen from the left eye visibly has 
a position at right angles to the axis of that eye, and intersects — 
the corresponding image of the right eye, in a line of common | 
intersection crossing each image where that image, whether re 
ferred back to the retina or to the distance of the transverse — 
piece itself, would be pierced by the optic axis. S 
n making these experiments, care should be taken not 0 
turn the axes into the oblique directions, to do which there 8 
always a strong inclination; for then the images, which were 
seen, in those directions as described, the one before or bebind — 
I will now proceed to answer an apparent objection. In 8 5 
first demonstration, under my proposition, I undertake ones : 
impression on the right eye from an object placed at Dis “ee : 
by the right eye, arguing that nothing else than a proj 
the manner described can account for the local relationship 
which these impressions are seen. The evidence of i : 
on” end is made the groundwork of my 
it may 3 that the evidence of consciou 
strong, that the impression 
i . ‘ 
seen, 
tance of the object itself at B.* 
ina la direction of the 
an object at B (fig. 1). : place ® 
atb. The lefvenseionn: of not be ree0e 
Again, take three equal, small rings of pasteboard. ce 
