indow-glass, but in real life this would hardly do; the
'property' spectacles would be detected at once and give rise to
suspicion.

"The personator is therefore in this dilemma: if he wears actual
spectacles, he cannot see through them; if he wears sham spectacles of
plain glass, his disguise will probably be detected. There is only one
way out of the difficulty, and that not a very satisfactory one; but Mr.
Weiss seems to have adopted it in lieu of a better. It is that of using
watch-glass spectacles such as I have described.

"Now, what do we learn from these very peculiar glasses? In the first
place they confirm our opinion that Weiss was wearing a disguise. But,
for use in a room so very dimly lighted, the ordinary stage spectacles
would have answered quite well. The second inference is, then, that
these spectacles were prepared to be worn under more trying conditions
of light--out of doors, for instance. The third inference is that Weiss
was a man with normal eyesight; for otherwise he could have worn real
spectacles suited to the state of his vision.

"These are inferences by the way, to which we may return. But these
glasses furnish a much more important suggestion. On the floor of the
bedroom at New Inn I found some fragments of glass which had been
trodden on. By joining one or two of them together, we have been able to
make out the general character of the object of which they formed parts.
My assistant--who was formerly a watch-maker--judged that object to be
the thin crystal glass of a lady's watch, and this, I think, was
Jervis's opinion. But the small part which remains of the original edge
furnishes proof in two respects that this was not a watch-glass. In the
first place, on taking a careful tracing of this piece of the edge, I
found that its curve was part of an ellipse; but watch-glasses,
nowadays, are invariably circular. In the second place, watch-glasses
are ground on the edge to a single bevel to snap into the bezel or
frame; but the edge of this object was ground to a double bevel, like
the edge of a spectacle-glass, which fits into a groove in the frame and
is held by the side-bar screw. The inevitable inference was that this
was a spectacle-glass. But, if so, it was part of a pair of spectacles
identical in properties with those worn by Mr. Weiss.

"The importance of this conclusion emerges when we consider the
exceptional character of Mr. Weiss's spectacles. They were not merely
peculiar o