“I really think I must,” replied Carlyle grimly.  “Two hundred and fifty pounds the original of this cost, I believe.”

“Cheap, too; it would make five hundred pounds in New York to-day.  As I was saying, many are literally unique.  This gem by Kimon is—­here is his signature, you see; Peter is particularly good at lettering—­and as I handled the genuine tetradrachm about two years ago, when Lord Seastoke exhibited it at a meeting of our society in Albemarle Street, there is nothing at all wonderful in my being able to fix the locale of your mystery.  Indeed, I feel that I ought to apologize for it all being so simple.”

“I think,” remarked Mr. Carlyle, critically examining the loose threads on his left boot, “that the apology on that head would be more appropriate from me.”

THE KNIGHT’S CROSS SIGNAL PROBLEM

“Louis,” exclaimed Mr. Carrados, with the air of genial gaiety that Carlyle had found so incongruous to his conception of a blind man, “you have a mystery somewhere about you!  I know it by your step.”

Nearly a month had passed since the incident of the false Dionysius had led to the two men meeting.  It was now December.  Whatever Mr. Carlyle’s step might indicate to the inner eye it betokened to the casual observer the manner of a crisp, alert, self-possessed man of business.  Carlyle, in truth, betrayed nothing of the pessimism and despondency that had marked him on the earlier occasion.

“You have only yourself to thank that it is a very poor one,” he retorted.  “If you hadn’t held me to a hasty promise——­”

“To give me an option on the next case that baffled you, no matter what it was——­”

“Just so.  The consequence is that you get a very unsatisfactory affair that has no special interest to an amateur and is only baffling because it is—­well——­”

“Well, baffling?”

“Exactly, Max.  Your would-be jest has discovered the proverbial truth.  I need hardly tell you that it is only the insoluble that is finally baffling and this is very probably insoluble.  You remember the awful smash on the Central and Suburban at Knight’s Cross Station a few weeks ago?”

“Yes,” replied Carrados, with interest.  “I read the whole ghastly details at the time.”

“You read?” exclaimed his friend suspiciously.

“I still use the familiar phrases,” explained Carrados, with a smile.  “As a matter of fact, my secretary reads to me.  I mark what I want to hear and when he comes at ten o’clock we clear off the morning papers in no time.”

“And how do you know what to mark?” demanded Mr. Carlyle cunningly.

Carrados’s right hand, lying idly on the table, moved to a newspaper near.  He ran his finger along a column heading, his eyes still turned towards his visitor.

“‘The Money Market.  Continued from page 2.  British Railways,’” he announced.