"But I would add one word to his deduction," he added. "The word 'alone.'"
"'Alone'?" echoed Delcassé.
"I would make the statement thus: 'Those signals alone did not and could not cause the explosion.'"
Delcassé looked at him with puzzled eyes, and again ran his fingers impatiently through his hair.
"I do not understand," he said. "You are getting beyond me. What is your theory, then?"
The line in Crochard's brow deepened.
"It is a thing, sir," he answered slowly, "which I find difficult to express in words. There is, at the back of my mind, an idea, vague, misty, of which as yet I catch only the dim outlines. My process of reasoning is this: it is certain, as General Marbeau says, that the signals from the hut were, in themselves, harmless, or there would have been other explosions than that on board La Liberté. Wireless waves can be directed and concentrated only to a very limited extent. They can be made a little stronger in one general direction than in others, that is all. And, in this case, that general direction would have embraced all the ships at anchor in the harbour.
"There must, then, have been some other force which, at the appointed time, struck from this stream of signals a spark, so to speak, into the magazines of La Liberté, one after the other. That there was an appointed time we cannot doubt—we know that it was the moment of sunrise yesterday. That the magazines were fired one at a time, and at spaced intervals we also know. That they could not explode of themselves in that way seems certain.
"You will remember that the signals began more than an hour before sunrise, and continued for at least half an hour afterwards. We know that the signals were sent automatically. Why? Partly, no doubt, because it was necessary that they be absolutely regular; but also because the man who did this thing—who is himself, perhaps, the inventor of the method—chose to make no confidants, to have no accomplices, and he could not himself be in the hut to send the signals. Again you ask why. Not because of danger of discovery, since there was no such danger. I believe it was because it was necessary that he be somewhere else, directing from an angle, perhaps, that other force, so mysterious and so deadly. I seem to see two forces, travelling in converging lines, as two bullets might travel, their point of meeting the magazines of La Liberté. At the instant of their meeting, there is a shock, a spark—as though flint and steel met—and the magazine explodes—first the forward magazine, then the after magazine, then the main magazine—one, two, three! This is all mere guesswork, you understand, sir," Crochard added, in another tone, "but so I see it. And, after all, it is susceptible of proof."
"What proof?" demanded Delcassé.