He indicated the writing pad on which the entire conversation was recorded, as was the young inventor’s wont. Tom nodded. “I see that plain enough. I am inclined to think. Jack, that you made a big mistake in giving that chap the location of the _Sea King_.” “You do? Why?” But as he spoke there came into Jack’s mind an uncomfortable recollection of what Jupe had said about wreckers. “I don’t know just why,” was Tom’s frank response; “didn’t you ever have a feeling that somehow something you had done had been,—quite unintentionally,—a bad blunder?” “I know what you mean. I wish to goodness we knew who this X. Y. Z. was,—or is.” “Easy to find out.” “Easy to find out!” echoed Jack with a fine note of scorn, “about as easy as—as——” “Translating that cipher,” broke in Tom. “If we can read it we may have a good clew to Mister X. Y. Z. and his doings.” Jack laughed aloud. “Yes, ‘if,’” he said mockingly, “and if——” “I think I can do it,” said Tom quietly. “You do! Well, tackle it at once, then. I’m kind of worried, I don’t mind telling you, about that chap and his questions.” Tom picked up the sheet of paper with the numbers inscribed on it in a seemingly hopeless jumble. “I’ll take it to the engine-room with me and try to work it out and keep an eye on the motor at the same time. I like tackling propositions of this kind.” “Yes, you always were a nutcracker at school; but I fancy you’ll find that the toughest yet.” “I’m not so sure about that. Ciphers divide themselves up into groups pretty well, and I’ve half an idea that this is a very common one. Suppose you take a look at Jupe and take the wheel while he gets supper.” “By ginger, I’d forgotten all about that till this moment.” Jack glanced up at the clock affixed to the bulkhead. “Almost five o’clock. Time has flown certainly. Well, good luck, Tom, with that mess of figures, and if you find out anything from them about X. Y. Z. you’re entitled to a big hunk of credit on a silver platter.” Jupe, so Jack found, had kept the _Vagrant_ on her course to a hair’s breadth. The old fellow had been a sailor in his younger days, and the waters they were now traversing were not unfamiliar to him. He hailed the news that he was to get supper with pleasure, however. “Ah’ll cook yo’ boys as fine a meal as yo’ ebber sat down to,” he promised, as with a broad grin he surrendered the wheel and made aft to the galley, which was a small room forward of the cabin and between it and the engine-room. It was an hour later that Tom appeared on deck with a knitted brow, and several sheets of paper covered closely with cabalistic figuring. “Well?” said Jack. “Well, I’ve worked it out, and——” “You know who X. Y. Z. is, I hope?” “Why, no,” was the response in a puzzled tone, “I don’t know who he is, but I’ve learned considerable of what he is,—and I don’t much like it.” CHAPTER IV—A MARINE GAME OF BLIND-MAN’S BUFF