that Linder would put it in his study and do his sitting at the
window in it. And you were to know when he was there by seeing his
feet in the window, and give the signal when you saw him. It must
have been a signal to somebody pretty far off, or he wouldn't have
chosen so loud an instrument as a B-flat trombone."

"I can play the B-flat trombone louder as any man in the business,"
asserted Schlichting with proud conviction.

"But what gets me," pursued Average Jones, "is the purpose of the
signal. Whom was it for?"

"I don't know nothing," said the other complacently. "I only know
to play the B-flat trombone louder as any man in the world."

Average Jones paid him a lump sum, dismissed him and returned to the
Cosmic Club, there to ponder the problem. What next? To accuse
Ransom, the mysterious hirer of a B-flat trombone virtuosity,
without sufficient proof upon which to base even a claim of
cross-examination, would be to block his own game then and there,
for Ransom could, and very likely would, go away, leaving no trace.
Who was Ransom, anyway? And what relation, if any, did he bear to
Linder?

Absorbed in these considerations, be failed to notice that the club
was filling up beyond its wont. A hand fell on his shoulder.

"Hello, Average. Haven't seen you at a Saturday special night since
you started your hobby."