"If my theory is the true one," Crochard explained, "there must have been, somewhere, another installation to create the intercepting force, which, of course, must also be transmitted by ether waves, as wireless is, if it is to penetrate wood and steel. It must have been within an hour's walk—probably half an hour's walk—of the hut in the grove. For remember, the mechanism there was set going an hour before sunrise, and the man had then to reach his other mechanism, and have it ready to start at sunrise. It is for us to discover the place where this second mechanism was installed—and where it probably still remains."
"Yes, that would be proof," agreed Delcassé thoughtfully; "and for myself, I will say that I believe your theory the right one. But you have not yet explained the part played by the two watchers on the quay."
"Their part was that of watchers merely," said Crochard. "They were sent there to observe and to report to their master—as they did."
"As they did?"
"Surely it is evident," Crochard explained, "that, if our theory is true, they would hasten to report. Imagine their master's anxiety until he heard from them! As a matter of fact, their report was filed within fifteen minutes after the explosion. M. Lépine has it in his pocket."
Delcassé stared, uncomprehending; but Lépine, his face suddenly illumined, snatched out his pocket-book and produced the sheets of yellow tissue.
"Ah, yes, certainly!" he cried. "I was blind not to see it! The report was in a form agreed upon: 'We continue our trip as planned. All well.' You will understand now, sir," he added, to Delcassé, "the reason for the high opinion I entertain of this gentleman!"
"But that message was sent to Brussels," objected the Minister.
"It was sent 'restante.' A man was waiting at the post-office to receive it and forward it instantly to Berlin."
Delcassé's face was a study, as he turned this over in his mind.