ed a _trifling exaggeration_, while that
which is less offensive to me is designated as _absolute deformity_ and
error? Persons with one eye are _not good judges_ of distance, and this may
be easily tested thus:--Close one eye, and endeavour to dip a pen in an
inkstand at some little distance not previously ascertained by experiment,
with both eyes open; it will be found far less easy than would be imagined.
One-eyed people, from habit, contrive to judge of distance mainly by
_relative position_, and by moving the head _laterally_ cause a change
therein: to them, all pictures are, to an extent, stereoscopic.

I am really amazed that my advocacy of the radial, instead of the parallel,
position of the cameras should have been so misunderstood. Surely, it
cannot be seriously asserted that the former will produce _two_ vanishing
points, and the latter only one? And as to the supposition connected with
the boy, the ass, and the drum, a camera that would produce the effect of
showing both sides of the ass, both legs of the boy, and both heads of the
drum, _with a movement of only 2-1/2 inches_, whether radially or parallel,
would indeed be a curiosity. But if the motion of the camera extended over
a space sufficiently large to exhibit the phenomena alluded to, then it
would confirm what I have before advanced, viz. present the idea of a
_small model_ of the objects, which could be so placed as to show naturally
these very effects.

That the axes of the eyes are inclined when viewing objects, is readily
proved thus:--Let a person look across the road at any object--say a
shop-window; but stand so that a _lamp-post near him_ shall intervene, and
be in a _direct line_ between the observer's nose and the object viewed. If
he be requested to observe the post instead of the distant object, the
pupils of his eyes will be seen to approach one another; and on again
looking to the distant object, will instantly recede. The _range_ of vision
is another point that appears to be misunderstood, as we are differing
about words instead of facts. The column is an illustration that will
_exactly_ suit my views; for I call the _range_ of vision the same if taken
from side to side of the column, although it is perfectly true that the
tangents to the two eyes differ by the angle they subtend: but certainly
MR. WILKINSON'S case (Vol. viii., p. 181.) of seven houses and five
bathing-machines in one picture, and five houses and eight machines in the