"With your permission, I should like to smoke," said he. "I can follow my thought better."
"By all means," accorded the lady.
Darrow lighted his cigarette, puffed a moment, and continued:
"For instance, at three o'clock he threatens to send a 'sign' unless McCarthy leaves town by six. McCarthy does not leave town. Promptly at six the 'sign' comes. What do you make of it?"
Nobody stirred.
"Why," resumed Darrow, "how, if Monsieur X was a hundred miles or so away, as Eldridge figured, did he know that McCarthy had not obeyed him? We must suppose, from the probable fact of that knowledge, that either Monsieur X had an accomplice who was keeping him informed, or he must be near enough to get the information himself."
"There is a third possibility," broke in Jack. "Monsieur X might have sent along his 'sign' at six o'clock, anyhow, just for general results."
Darrow nodded his approval.
"Good boy, Jack," said he. "That is just the point I could not be sure about. But finally, at the time, you will remember, when I predicted McCarthy's disappearance, Monsieur X made a definite threat. He said," observed Darrow, consulting one of the bundle of papers he held in his hand:
"'My patience is at an end. Your last warning will be sent you at nine-thirty this morning. If you do not sail on the Celtic at noon, I shall strike,' and so forth. The Celtic sailed at noon, without McCarthy. At twelve thirty came the first message to the people calling on them to deliver up the traitor that is among you.' How did Monsieur X know that McCarthy had not sailed on the Celtic? The answer is now unavoidable: either an accomplice must have sent him word to that effect, or he must have determined the fact for himself.