For a few seconds he remained silent. I saw that he was reflecting deeply. "Well," he said. "We've established listening-posts all round London for its protection." "A real benefit they are!" I laughed. "We have officers and men listening all night, it is true. Of course as a picturesque fiction in order to allay public curiosity they publish photographs of men listening to things like gramophone-trumpets." "Exactly. The theory of that new invention is extremely sound. That's my opinion." "And mine also," I said. "I hear that the inventor has told the authorities that if they will assist him to complete his machine--which I expect is a costly affair--he will be able to carry out daily raids on Cuxhaven, Essen, Dusseldorf, and even as far as Berlin; carrying several tons of explosives." "How many?" asked my friend. "Oh! four or five it is said." "Phew!" remarked Lionel, again stirring in his bed. "That sounds really healthy--doesn't it?" "Yes--the realisation of the dream of every flying-man to-day," I said. Then our conversation drifted into another channel, and, half an hour later, I left him. During the past few days Teddy and I had been very busy with our own invention, and had made a number of further experiments down at Gunnersbury. We could easily direct the electric current upon those insulated steel guys around our distant wireless-pole, but our difficulty was how to increase our power without increasing the bulk of the apparatus which we should be compelled to take up in the monoplane for purposes of attacking a Zeppelin. There was a limit to the weight which my Breguet with its 200 horse-power engines would carry, and though, of course, we believed it would be unnecessary to use bombs, yet some should be carried for purposes of defence, as well as a Lewis gun. Therefore we were faced by a very difficult problem, that of weight. The next day was Sunday, and Teddy having returned from Yarmouth, we spent the whole afternoon and evening down at the workshop, making further experiments. I had not seen Roseye since Friday evening, which I had spent at Lady Lethmere's, Sir Herbert being absent in Liverpool. Therefore, as we had carried out an alteration of the apparatus and intended to try sparking upon the pole again after dark, I rang Roseye up on the telephone shortly after five o'clock. Mulliner, Lady Lethmere's maid, replied, and a few minutes later Lady Lethmere herself spoke to me. "Oh, I've rung you up at your rooms half a dozen times to-day, Mr Munro--but could get no answer!" she said. "Being Sunday, my man is out," I exclaimed. "I'm down here at Gunnersbury." "Can you take a taxi at once, and come over and see me?" she urged. "I want to speak to you immediately." "What about?" I asked anxiously. "I can't say anything over the telephone," she answered in a distressed voice. "Do come at once, Mr Munro. I am in such trouble."