248 
Dr. Wollaston on the 
Though it may not be possible to demonstrate, by any 
decisive experiment on the eyes of living persons, what those 
circumstances are, still we may find convincing arguments 
to prove their influence, if it can be shown in the case of 
portraits, that the same ready decision we pronounce on the 
direction of the eyes is founded, in great measure, on the 
view of parts which, as far as I can learn, have not been 
considered as assisting our judgement. 
Previous to a full examination of this question, one might 
imagine that the circular form of the iris would be a sufficient 
criterion of the direction in which an eye is looking, since, 
when the living eye is pointed to us, this part is always cir- 
cular, but cannot appear strictly so, when turned in such a 
manner that we view it with any degree of obliquity. But, 
upon farther consideration, it is evident that we cannot judge 
of exact circularity with sufficient precision for this purpose, 
even when the whole circle is fully seen, and in many cases 
we see too small a portion of the circumference of the iris to 
distinguish whether it is circular or elliptic. 
Moreover, in a portrait, although the iris be drawn most 
truly circular, and consequently will appear so when we 
have a direct view of it, still, in all oblique positions, it must 
be seen as an ellipse. And yet the eyes, as is well known, 
apparently continue to look at the spectator, even when he 
moves to view them very obliquely, and sees them of a form 
most decidedly elliptic. 
The reason why the eyes of a portrait seem to follow us 
will be hereafter considered, but cannot be rightly explained 
until the circumstances, on which apparent direction in the 
front view depends, are fully understood. 
