Naturally any track of that nature was totally unexplored by me; but I was far from dismissing it on that account. Here again my ignorance of modern War came in to humble me. For what is the good of saying things are fantastic and far-fetched--sound-ranging and the selenium cell and what not--when for a number of years the food we have eaten and the clothes we have worn and the roofs over our heads have depended on just such fantasies? Not for nothing were those clusters of listening cones at Hyde Park Corner and on Parliament Hill, not for nothing those wireless masts over our heads at that very moment. Their operation might be unfamiliar to me, but these things were the daily business of Commander Hubbard, R.N. He turned as naturally to them as I myself turn to those equally mysterious things, a man's motives and the operative emotions of his heart. "For all that," said Hubbard abruptly, "I should like to have a good look at that cellar of his." I was silent. I didn't know whether his wish to see the cellar included sound-experiments on the roof also. "More than that," he continued slowly, "--by the way, did Mrs. Esdaile and the children get away?" That I did not know. "Well, what about going round this evening to see?" "The chances are that they did if I know Philip." "I don't mean that. I mean what about going round to see that cellar," Hubbard replied. I didn't say so, but I had a sudden wonder, quite new and born all at once of I don't know what, whether Esdaile might want us to see his cellar. V However, we went, and at a little after eight o'clock rang the bell we had rung under such very different circumstances at breakfast-time that morning. The parachute still waved in the mulberry, and a few policemen were unobtrusively hanging about the street. Two of these did not move very far from the gate. I supposed that in view of pending inquiries it was important that the parachute should not be touched. We waited so long for an answer after ringing the bell that I had almost concluded there was nobody at home. We were, in fact, on the point of turning away when Esdaile himself opened the door. Poor devil! I learned presently that he had had callers enough that afternoon to make him wish to disconnect his bell altogether--interested parties of all sorts, a dozen of them at least. He had as a matter of fact removed his telephone receiver from the hook. He said its ringing had nearly driven him mad.