“How do you know it’s the Seer?” I asked.

“Look at the green ink,” he answered.  “Besides, I recollect the very shape of the last flourish.  I flourished a bit like that in the excitement of the moment, which I don’t always do with my regular signature.”

“He’s done us,” I answered, recognising it.  “But how the dickens did he manage to transfer it to the cheque?  This looks like your own handwriting, Charles, not a clever forgery.”

“It is,” he said.  “I admit it—­I can’t deny it.  Only fancy his bamboozling me when I was most on my guard!  I wasn’t to be taken in by any of his silly occult tricks and catch-words; but it never occurred to me he was going to victimise me financially in this way.  I expected attempts at a loan or an extortion; but to collar my signature to a blank cheque—­atrocious!”

“How did he manage it?” I asked.

“I haven’t the faintest conception.  I only know those are the words I wrote.  I could swear to them anywhere.”

“Then you can’t protest the cheque?”

“Unfortunately, no; it’s my own true signature.”

We went that afternoon without delay to see the Chief Commissary of Police at the office.  He was a gentlemanly Frenchman, much less formal and red-tapey than usual, and he spoke excellent English with an American accent, having acted, in fact, as a detective in New York for about ten years in his early manhood.

“I guess,” he said slowly, after hearing our story, “you’ve been victimised right here by Colonel Clay, gentlemen.”

“Who is Colonel Clay?” Sir Charles asked.

“That’s just what I want to know,” the Commissary answered, in his curious American-French-English.  “He is a Colonel, because he occasionally gives himself a commission; he is called Colonel Clay, because he appears to possess an india-rubber face, and he can mould it like clay in the hands of the potter.  Real name, unknown.  Nationality, equally French and English.  Address, usually Europe.  Profession, former maker of wax figures to the Museé Grévin.  Age, what he chooses.  Employs his knowledge to mould his own nose and cheeks, with wax additions, to the character he desires to personate.  Aquiline this time, you say.  Hein!  Anything like these photographs?”

He rummaged in his desk and handed us two.

“Not in the least,” Sir Charles answered.  “Except, perhaps, as to the neck, everything here is quite unlike him.”

“Then that’s the Colonel!” the Commissary answered, with decision, rubbing his hands in glee.  “Look here,” and he took out a pencil and rapidly sketched the outline of one of the two faces—­that of a bland-looking young man, with no expression worth mentioning.  “There’s the Colonel in his simple disguise.  Very good.  Now watch me:  figure to yourself that he adds here a tiny patch of wax to his nose—­an aquiline bridge—­just so; well, you have him right there; and the chin, ah, one touch:  now, for hair, a wig:  for complexion, nothing easier:  that’s the profile of your rascal, isn’t it?”