French hesitated.
“For the moment the outlook’s not very cheery,” he said at last. “All the same I can’t believe that boat can go away out of the Scheldt and disappear. In my judgment she’s bound to be reported before long, and I’m looking forward to getting word of her within the next day or so. Then I have no doubt that the tracing is some kind of cipher, and if we could read it we should probably get light on the whole affair.”
“Why shouldn’t you read it? Try it again.”
“I intend to, sir. But I don’t hope for much result, because I don’t believe we’ve got the genuine document. I don’t believe they would have handed it, nor a copy of it either, to a man they intended to murder, lest it should be found on his body. I’d state long odds they gave him a fake.”
“I think you’re probably right,” the chief admitted. “Try at all events. You never know your luck.”
He bent over his desk, and French, realizing that the interview had come to an end, quietly left the room. Then, seeing there was nothing requiring his attention urgently, and tired after his journey, he went home.
But contrary to his expectations, the next day passed without any news of the L’Escaut, and the next, and many days after that. Nor could all his efforts with the tracing throw any light on that mysterious document. As time passed he began to grow more and more despondent, and the fear that he was going to make a mess of the case grew steadily stronger. In vain he laid his difficulties before his wife. For once that final source of inspiration failed him. Mrs. French did not take even one illuminating notion. When the third week had gone by, something akin to despair seized upon the Inspector. The only possibility of hope now seemed to lie in the return of Arnold Price, and French began counting the days until his arrival.
One night about three weeks after his return from Belgium he settled down with a cigar after dinner, his thoughts running in their familiar groove: What were these people engaged on? Was there any way in which he could find out? Had he overlooked any evidence or any inquiries? Had he neglected any possible line of research?
The more he considered the affair in all its bearings, the more conscious he became of the soundness of the advice he had given to Cheyne, and which in his turn he had received from his chief. Unquestionably in the tracing lay the solution he required, and once again he racked his brains to see if he could not by any means devise a way to read its message.
On this point he concentrated, going over and over again everything he had learned about it. For perhaps an hour he remained motionless in his chair, while the smoke from his cigar curled up and slowly dissolved into the blue haze with which the room was becoming obscured. And then suddenly he sat up and with a dawning, tremulous eagerness considered an idea which had just leaped into his mind.