with you, Mr. Vernon. It is a puzzling affair, and I confess I
don't know what to make of it. But it is exceedingly interesting, and I
am very glad that you have confided in me. I think it will be best if
we keep our knowledge strictly to ourselves for the present."

"By all means."

"I except the detectives who are working on the case."

"Yes, of course. They are the proper persons to utilize the
information," assented Jack. "It should not be made public."

"I never knew that a copy of Von Whele's picture was in existence," said
Mr. Lamb. "I need hardly ask if it is a faithful one."

"I am afraid it is," Jack replied, smiling. "I worked slowly and
carefully, and though I was a bit of an amateur in those days, I was
more than satisfied with the result. The pictures were of the same size;
and I really don't think many persons could have distinguished the one
from the other."

"Could _you_ do that now, supposing that both were before you, framed
alike, and that the duplicate was cunningly toned to look as old as the
original?"

"I should not hesitate an instant," Jack replied, "because it happens
that I took the precaution of making a slight mark in one corner of my
canvas."

"Ah, that was a clever idea--very shrewd of you! It may be of the
greatest importance in the future."

"You have not yet given me your opinion of the mysterious Frenchman,"
Jack went on. "Do you believe that he was concerned in both robberies?"

"Circumstances seem to point that way, Mr. Vernon, do they not? Your
picture was certainly taken before mine?"

"It was, without doubt."

"Then, what object could the Frenchman have had in stealing the
comparatively worthless duplicate, unless he counted on subsequently
getting possession of the original?"

"It sounds plausible," said Jack. "That's just my way of looking at it.
The advantage would be--"

"That the thieves would have two pictures, equally valuable to them, to
dispose of secretly," put in Mr. Lamb. "We may safely assume, then, that
our enterprising burglars are in possession of a brace of Rembrandts.
What they will do with them it is difficult to say. They will likely
make no move at present, but it is possible that they will try to
dispose of them in the Continental market or in America, in which case
I have hopes that they will blunder into the hands of the police. Proper
precautions have been taken both at home and abroad."

"Is there any clew yet?"

Mr. Lamb shook his