"Anyway, I'm sure the feller wouldn't be an engineer, 'cause mostly they're behind the lines. So I thought maybe he'd be a surgeon----" Mr. Conne was whistling, almost inaudibly, his eyes fixed upon the flagpole opposite. "He was educated at Heidelberg," said he. "I didn't think of that," said Tom. "It's where he met L." Tom said nothing. His line of reasoning seemed to be lifted quietly away from him. Mr. Conne was turning the kaleidoscope and showing him new designs. "He took L. home for the holidays," he quietly observed. "Old Piff and the boys." "I--I didn't think of that," said Tom, rather crestfallen. "You didn't ride fast enough and make enough noise," Mr. Conne said. His eyes were still fixed on the fluttering tricolor and he whistled very low. Then he rubbed his lip with his tongue and aimed his cigar in another direction. "They were studying medicine there, I guess," he mused. "That's just what my idea's about," said Tom. "It ain't an idea exactly, either," he added, "but it's kind of come to me sudden-like. You know what a _hunch_ is, don't you? There's something there about somebody having a cataract, and that's something the matter with your eyes; Mr. Temple had one. So maybe that feller L. that he met again is an eye doctor. Long before the war started they told Mr. Temple maybe he ought to go to Berlin to see the eye specialists there--'cause they're so fine. So maybe the spy is a surgeon and L. is an eye doctor. It says how he met him again on account of somebody having a cataract. And he said the way of bringing the code key was L.'s idea. I read about a dentist that had a piece of paper with writing on it rolled up in his tooth. He was a spy. So that made me think maybe L.'s idea had something to do with eyes or glasses, as you might say." "Hmm! Go on. Anything else?" "But, anyway, that ain't the idea I had. In Temple Camp there was a scout that had a little pocket looking-glass and you couldn't see anything on it but your own reflection. But all you had to do was to breathe on it and there was a picture--all mountains and a castle, like. Then it would fade away again right away. Roy Blakeley wanted to swap his scout knife for it, but the feller wouldn't do it. On the back of it it said _Made in Germany_. It just came to me sudden-like that maybe that was L.'s idea and they'd have it on a pair of spectacles. Maybe it's a kind of crazy idea, but----" He looked doubtfully at Mr. Conne, who still sat tilted back, hat almost hiding his face, cigar sticking out from under it like a camouflaged field-piece. He was whistling very quietly, "_Oh, boy, where do we go from here?_" He had whistled that same tune more than a year before when he was waiting for a glimpse of "Dr. Curry," spy and bomb plotter, aboard the vessel on which Tom was working at that time. He had whistled it as he escorted the "doctor" down the companionway. How well Tom remembered! "Come on, Tommy," he said, jumping suddenly to his feet.