"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?"