We furnished him with an empty suit-case, and, from the window, watched him making for Mitre Court at a smart double.
"I wonder if he will find the booty," said Thorndyke. "It just depends on whether the hiding-place was known to more than one of the gang. Well, it has been a quaint case, and instructive, too. I suspect our friend Barton and the evasive Schönberg were the collaborators who produced that curiosity of literature."
"May I ask how you deciphered the thing?" I said. "It didn't appear to take long."
"It didn't. It was merely a matter of testing a hypothesis; and you ought not to have to ask that question," he added, with mock severity, "seeing that you had what turn out to have been all the necessary facts, two days ago. But I will prepare a document and demonstrate to you to-morrow morning."
"So Miller was successful in his quest," said Thorndyke, as we smoked our morning pipes after breakfast. "The 'entire swag,' as he calls it, was 'up the chimbly,' undisturbed."
He handed me a note which had been left, with the empty suit-case, by a messenger, shortly before, and I was about to read it when an agitated knock was heard at our door. The visitor, whom I admitted, was a rather haggard and dishevelled elderly gentleman, who, as he entered, peered inquisitively through his concave spectacles from one of us to the other.
"Allow me to introduce myself, gentlemen," said he. "I am Professor Poppelbaum."
Thorndyke bowed and offered a chair.
"I called yesterday afternoon," our visitor continued, "at Scotland Yard, where I heard of your remarkable decipherment and of the convincing proof of its correctness. Thereupon I borrowed the cryptogram, and have spent the entire night in studying it, but I cannot connect your solution with any of the characters. I wonder if you would do me the great favour of enlightening me as to your method of decipherment, and so save me further sleepless nights? You may rely on my discretion."