“Hold on, till we finish this,” said Tom. “We’ll talk things over as soon as I get this screw set.” I watched him idly as he worked. “What is he trying to do now?” I asked Dorothy. Just as I spoke, Tom moved his hand, the low buzz of a Ruhmkoff coil broke in on the silence of the room, and the glorious beauty of the tube of unknown gas that we had found in Heidenmuller’s laboratory illumined the place. “Why, there’s the gas tube,” I cried in amazement. “Yes,” said Dorothy. “From that tube has come a marvellous development of the Denckel apparatus. Tom has been able to receive with it right along, but never send. One day he thought of placing that tube of gas in the circuit, and now he can send, as well as receive. Tom has done a big thing. He can reverse the action of the machine, not only receive a message from any place, but shoot a wireless back across space, and have it strike exactly where he wishes. It’s really a wonderful development, but I don’t see how it’s going to help us find ‘the man,’ and I don’t want to give up. There, Tom is finishing. We’ll talk things over now.” “If ‘the man’s’ crusade were not over, it might be even more effective,” I remarked reflectively. “It would have been strange enough if we had found him by means of the gas released from metal destroyed by his terrific power.” “It would have been,” answered Dorothy. I stood watching Tom, as, pipe in mouth, he set the revolving belt in motion and watched the moving cylinders. “To what strength of wave is it adjusted?” I asked. “I’ve put it on the high,” said Tom. “It’s fixed for ‘the man’s’ waves. I’ve got one new dodge, though, among others. I have it arranged so I could have told at any time whether ‘the man’ was sinking a ship or just experimenting. It’s so delicate that when his waves strike a ship, the machine can tell it by the slight loss in power. See here,” he turned on the switch in its revolution, “it’s this.” Flash went the beam. A groan burst from Dorothy’s lips. “He’s at it again. There’s a ship gone down.” Tom’s face was ghastly. “That’s right,” he said. “Where is he?” Five minute’s calculation brought it. “He’s in Tokio,” said Dorothy. Tom nodded. “What a fiend to have loose in the world. Here his mission is accomplished and war is over, and he keeps on.” Dorothy sprang from her chair. “No, it isn’t that. I’m sure of it. He doesn’t know that war is over. It must be that. We must tell him of it.” CHAPTER XIX “What is your idea, Dorothy?” asked Tom gravely. This last catastrophe, coming when all danger from the man who had stopped all war seemed past, had sobered us all. “You said there was a mast with wires beside the conning tower of the submarine, that time you saw ‘the man,’ didn’t you, Jim?” she asked. I nodded.