“Certainly,” said Dorothy smiling. “We know that the reflectoscopes were charged by a wave which ‘the man’ sent out from some definite spot. Theoretically, that place might be anywhere in the world. Practically, it’s probably somewhere not many miles from the ship he is destroying. But it is somewhere. His waves start from some definite point. There is some single point of generation. Now, with this machine, I ought to be able to find out just where the place is from which the wave starts, and not only within a hundred miles, but within a very brief space. Say, for instance, we had the machine in London, I could tell that ‘the man’ started his waves from Sandy Hook, and not from Hell Gate. That power of fixing the exact position of ‘the man’ gives us a tremendous step.” “Absolutely tremendous,” I cried, and Tom chimed in, his eyes blazing with enthusiasm. “Here’s to the successful working out of the new clue.” The announcement of dinner made rather an anti-climax to our discovery. Tom laughed--“Well, we’ve got to eat, anyway. Come on.” No feast could equal a dinner with Dorothy as hostess. Never did her sweet face look more charming than when she presided at her own board. The talk soon became confined to technicalities, as Dorothy and Tom discussed the possibilities of the new apparatus, and I sat watching Dorothy’s expressive face, as she talked of velocities and lengths, methods of generation and of control. But her absorption in her subject lasted but a brief time. Dinner over she turned to the piano. Then for two hours her music wafted me through many a lofty old Iberian turret. As I walked to my rooms from the Haldanes’, I revelled in every breath of the city air. The very noises of the street exhilarated me, as I strolled along, one of the crowd, and a free man. The unexpected setback of my arrest now safely over, I could attack the new clue with eagerness, and the early morning found all three of us at the Hamburg-American pier. No trace of any such invoice as Carl Denckel had described was to be found in any of the office records. Book after book was searched for some account of the shipment, but in vain. As a last resort, we went out to the huge warehouses and searched them, up and down, back and forth. The morning passed in unavailing work. We swung up town to lunch, and then turned again to our task. The most unruly of warehouse men turned into an obedient slave at Dorothy’s behest, and from one long bare shed to another we passed, escorted by a retinue of willing workers. We paused at length at the end of the pier, where the big doors looked out on the water, glowing beneath the sun. The burly Irishman who had been our escort from the first took off his cap and wiped his wet brow. “I’m feared it’s no use, mum,” he said apologetically. “Shure and I’d go on fer hours huntin’ fer you, if ’twas anny use, but it’s niver a bit. We’ve been iverywhere that a machine loike thot could be.”