"But we're in possession of one thread now that may guide us through the maze," said McGinity, settling down finally in a chair opposite me. "I admit that what we have to deal with is most extraordinary--almost inexplicable--" he went on; "but here's this much to remember--your own idea, by the way--if this mystery was contrived and worked out by a human mind, then a human mind can discover what it is." "Quite right," I agreed. "And if the person who made the scroll is the same one who sent those Martian radio messages, and dropped the rocket--" "Dropped?" McGinity exclaimed, interrupting me. "Of course, that rocket was _dropped_ on the water-front. Dropped! That idea had never occurred to me before. It wouldn't surprise me, Mr. Royce, if you've hit on another clue." "Yes?" I said, a little bewildered. "Anyway," I began again, "if it is the same person, then I'm sure we can trace him." "I'll tell you what I think, Mr. Royce," McGinity said; "we shall have to go back--and go back a long way, and find all we can about--Olinski." "Olinski?" I exclaimed. "Surely, you don't suspect him?" "He's a radio wizard, isn't he?" the reporter said. "He may have sent those alleged messages from Mars himself. He may have directed them to the moon, round ten o'clock, each night, during the experiments, and they were echoed, or bounced, back to earth. I understand he's quite an inventor besides. Now, he may have invented that rocket--everything--" "You're forgetting, McGinity," I interrupted. "He couldn't possibly have invented Mr. Zzyx." "That's so--I'd forgotten Mr. Zzyx," the reporter admitted. "All the same, just to be on the safe side, I think we'd better trace Olinski's career." "We must remember this," I suggested, "that whoever is at the bottom of this fraud--if it is a fraud--had a definite purpose in putting it over. In criminology, that is called motive. Once you have the motive, the rest comes easier." "I agree on that, Mr. Royce," said McGinity. "But the thought has just come to me that the perpetrator of this hoax--and I'm convinced now it is a hoax--has got nearly three months' start. Let's suppose, as you suggested, that he's a man who had some definite purpose in putting it over, the man we want to find. Very well, he pulls his two big tricks late in August, the Martian radio message in code, and the rocket from outer space, both occurring on the same night; and from that time, he passes into the unknown. No more messages from Mars. Everything cleaned up in one night." "On that supposition," I said, "we shall, of course, have to eliminate Olinski, for which I shall be very glad."