"Several of my surmises in this case proved entirely correct," he said. "My first suspicion was aroused that if spies were about, they would probably prepare for tapping the telegraph lines, and, as you know, I soon discovered evidence of it. Then those staples in the foundations of the bridge gave me a further clue to the work in progress, a suspicion greatly strengthened by the signal light shown by the man Klauber. The two men who held the safe keys being members of the Golf Club aroused a theory which proved the correct one, and on tracing back the career of the waiter I made a remarkable discovery which left no doubt as to his real profession. It seems that while employed at the Café de l'Europe in London, he lodged at the house of Mrs. Jephson, in Shepherd's Bush, and became extremely friendly with the widow's son. Now you'll remember that a few days before the poor fellow's death he was absent mysteriously, and on his return he told his mother in confidence that there would shortly be something in the papers about himself. Well, the truth is now quite plain. During his absence he evidently came up here. Young Jephson, who knew German, had found out that his German friend was a spy, and had no doubt secured the document afterwards found upon him as evidence. Klauber was ignorant of this, though he suspected that his secret was out. In deadly fear of exposure, he then plotted to silence the young Englishman, inducing him to walk along the towing-path between Hammersmith and Barnes, where he no doubt pushed him into the river. Indeed, I have found a witness who saw the two men together in King Street, Hammersmith, on the evening of the poor fellow's disappearance. The plan which Reitmeyer saw is, I find, fortunately one of the discarded ones." "Extraordinary!" I declared, absorbed by what he had related. "But while you've wrested from Germany the secrets of some of our most important defences, you have, my dear Ray, temporarily lost the woman you love!" "My first duty, Jack, is to my King and my country," he declared, sitting on the edge of the table in the spies' photographic studio. "I have tried to perform it to-night, and have, fortunately, exposed the German activity in our midst. When the police arrive to view this spies' nest, we must at once search for her who is always my confidante, and to whose woman's wits and foresight this success is in no small measure due." CHAPTER II THE SECRET OF THE SILENT SUBMARINE "It's a most mysterious affair, no doubt," I remarked. "Has anything further been discovered?" "Yes, Jack," replied my friend Ray Raymond, rolling a fresh cigarette between his fingers. "On investigation, the mystery grows more complicated, more remarkable, and--for us--much more interesting."