"There were fifty-two when I put them in my pocket," said von Ludwig, "because I counted them." Again Jack ran through the deck There were but fifty-one cards. Suddenly the lad gave a start. He spread the cards out in the bottom of the boat, making four piles all suits together. He counted the hearts. They were all there, thirteen of them. He counted the clubs. They were all there, too. Next he counted the spades. All were there. Last he counted the diamonds. There were but twelve. Jack arranged them in order. There was one card shy. Jack found what it was a moment later. There was no six of diamonds in the deck. For some moments Jack sat silent, staring at the cards before him. He had been struck with a great light. "So!" he said to himself at last, "Harris cheated." "What's that?" said Frank, who had heard Jack's muttered words, but had not caught their import. "I said," replied Jack, slowly, "that Harris cheated." Frank was surprised. A moment later he said: "Well, even if he did, he lost anyhow." "That's it," said Jack, quietly. "He didn't lose." "You mean----" exclaimed Frank, excitedly. "Yes; I mean that I lost. I should have been the one to stay." "Impossible," said Frank. "It's true," declared Jack. "Von Ludwig here says the deck was a full deck. It's shy a card now. The six of diamonds is missing. That is the card Harris cut first. You remember he turned aside?" "Yes, but----" "That's when he slipped the six of diamonds out of sight and exposed the deuce of spades." "What's all this talk about cards?" asked von Ludwig, at this juncture. Jack explained and for a few moments von Ludwig was lost in thought. "You know," he said, finally, "I think more of that fellow every minute. That's the one case I have ever heard of where a man cheated with honor." There was silence aboard the little craft as it sped over the water, all three aboard keeping a close watch for the approach of a German vessel of some sort. Von Ludwig referred to his chart occasionally, for he wished to steer as clear of mines as possible. They might be deep in the water and they might be close to the surface. There was no use taking chances. And while the voyage continued the lads were to be treated to yet another surprise; but this surprise was to be a pleasure and would not bring heavy hearts, as had the discovery of the missing card. "I wish," said Jack, suddenly, to von Ludwig, "that you would tell me who you really are. I sit here and look at you and know I should be able to call your name. But I can't do it and it makes it decidedly unpleasant." Von Ludwig smiled. "I should have thought you would know me in a minute in spite of my disguise," he said quietly. "I am sure I should have known both of you no matter what pains you took to conceal your features." "You're only making matters worse," said Frank. "Come on now and tell us who you are."