stamped upon the cover, and was beginning to inspect it when Mrs. Hornby
rose and stood beside him.

"That," said she, as she opened the book at the first page, "is the
thumb-mark of a Miss Colley. She is no connection of ours. You see it is
a little smeared--she said Reuben jogged her elbow, but I don't think he
did; at any rate he assured me he did not, and, you know--"

"Ah! Here is one we are looking for," interrupted Thorndyke, who had
been turning the leaves of the book regardless of Mrs. Hornby's rambling
comments; "a very good impression, too, considering the rather rough
method of producing it."

He reached out for the reading lens that hung from its nail above the
mantelpiece, and I could tell by the eagerness with which he peered
through it at the thumb-print that he was looking for something. A
moment later I felt sure that he had found that something which he had
sought, for, though he replaced the lens upon its nail with a quiet and
composed air and made no remark, there was a sparkle of the eye and a
scarcely perceptible flush of suppressed excitement and triumph which I
had begun to recognise beneath the impassive mask that he presented to
the world.

"I shall ask you to leave this little book with me, Mrs. Hornby," he
said, breaking in upon that lady's inconsequent babblings, "and, as I
may possibly put it in evidence, it would be a wise precaution for you
and Miss Gibson to sign your names--as small as possible--on the page
which bears Mr. Reuben's thumb-mark. That will anticipate any suggestion
that the book has been tampered with after leaving your hands."