Meanwhile Wilson followed Mr. Mitchel to Broadway then down to the Casino, where he stopped to buy tickets; then out again, and down Broadway to the Fifth Avenue Hotel, which he entered. He nodded to the clerk, took his key, and passed up-stairs. Evidently he lived there. Wilson of course had no further definite instructions. From Mr. Barnes's backward nod, he had understood that he was to shadow this man, and under the circumstances it was his simple duty to do this until relieved by further orders. In these days of telephones it is easy enough to make hurried reports to head-quarters and then continue the pursuit. The Fifth Avenue is not a promising place in which to watch a man, provided the man knows that he is being watched. It has three exits--one on Broadway, and one each on Twenty-third and on Twenty-fourth Streets. Wilson flattered himself that Mr. Mitchel was unsuspicious, and therefore whichever way he might leave the building, he would first return his key at the desk. He consequently kept that point in view. Not half an hour had elapsed when his man appeared, gave up his key, as expected, and passed out by the Broadway door. Crossing the Avenue, he walked down Twenty-third Street, eastward; Wilson followed cautiously, going through the Park. At Third Avenue Mr. Mitchel climbed the elevated stairway, and Wilson was compelled to do the same, though this brought him unpleasantly close. Both men took the same train, Mr. Mitchel in the first coach, Wilson the last. At Forty-second Street Mr. Mitchel left the train, and crossed the bridge, but instead of taking the annex for the Grand Central Depot, as one is expected to do, he slipped through the crowd to the main platform and took a train going back down-town. Wilson managed to get the same train, but he realized at once that his man either knew that he was followed, or else was taking extraordinary precautions. At Thirty-fourth Street station the trick was repeated, Mr. Mitchel crossing over the bridge and then taking an up-town train. What puzzled Wilson was that he could not detect that his man had noticed him. It seemed barely possible, as they had encountered crowds at both places, that he had escaped unobserved. He was more satisfied of this when, at Forty-second Street again, Mr. Mitchel once more left the train, crossed the bridge, and this time went forward, taking the coach for the Grand Central. Evidently all the manoeuvring had merely been prompted by caution, and not having observed his shadow, the man was about to continue to his true destination. Mr. Mitchel had entered the coach by the first gate, and was seated quietly in the corner as Wilson passed on, going in by the gate at the opposite end. A moment later the guard slammed the gate at Wilson's end, and pulled the bell-rope. As quick as a flash Mr. Mitchel jumped up, and before he could be prevented, had left the coach just as it started, carrying away Wilson, completely outwitted and dumbfounded.