dinburgh Mystery."

He was gone. Polly looked again at the photo of David Graham. Did a
crooked mind really dwell in that crooked body, and were there in the
world such crimes that were great enough to be deemed sublime?

CHAPTER XVIII

THE THEFT AT THE ENGLISH PROVIDENT BANK

"That question of motive is a very difficult and complicated one at
times," said the man in the corner, leisurely pulling off a huge pair of
flaming dog-skin gloves from his meagre fingers. "I have known
experienced criminal investigators declare, as an infallible axiom, that
to find the person interested in the committal of the crime is to find
the criminal.

"Well, that may be so in most cases, but my experience has proved to me
that there is one factor in this world of ours which is the mainspring
of human actions, and that factor is human passions. For good or evil
passions rule this poor humanity of ours. Remember, there are the women!
French detectives, who are acknowledged masters in their craft, never
proceed till after they have discovered the feminine element in a crime;
whether in theft, murder, or fraud, according to their theory, there is
always a woman.

"Perhaps the reason why the Phillimore Terrace robbery was never
brought home to its perpetrators is because there was no woman in any
way connected with it, and I am quite sure, on the other hand, that the
reason why the thief at the English Provident Bank is still unpunished
is because a clever woman has escaped the eyes of our police force."

He had spoken at great length and very dictatorially. Miss Polly Burton
did not venture to contradict him, knowing by now that whenever he was
irritable he was invariably rude, and she then had the worst of it.

"When I am old," he resumed, "and have nothing more to do, I think I
shall take professionally to the police force; they have much to learn."

Could anything be more ludicrous than the self-satisfaction, the
abnormal conceit of this remark, made by that shrivelled piece of
mankind, in a nervous, hesitating tone of voice? Polly made no comment,
but drew from her pocket a beautiful piece of string, and knowing his
custom of knotting such an article while unravelling his mysteries, she
handed it across the table to him. She positively thought that he
blushed.

"As an adjunct to thought," she said, moved by a conciliatory spirit.

He looked at the invaluable toy which the young girl had tantalisingly
placed close to h