"Stir your stumps," was his peremptory address to the boys, and they trotted to catch his long stride out of the hotel. The sidewalks on both sides of the street were crowded with curious onlookers, attracted by the reported doings inside. Roque bucked the line like a football star, and Billy and Henri followed in the cleared space without special exertion. "He doesn't care whom he pushes," observed Billy, as he listened to angry protests along the line of travel. Both of the boys were eager to talk over the latest disappearing act of that wonderful Anglin, but not so anxious as to take chances with Roque in earshot. The secret agent turned into a silent side street, and stopped before a heavily grated door in the gloomy front of a solid stone building that was a skyscraper in height. Reaching through the grating, he evidently opened way of communication with the interior, for in a moment or two a glimmer of light splintered through the barred entrance, the ponderous lock creaked, and the door swung back on its massive hinges. A skull cap and a gray beard showed behind the lamp shining in the doorway. Roque pushed the boys ahead of him, and their closing in was marked by a clang behind them. They followed their guide through a long corridor and into a modern high-power elevator, that shot noiselessly upwards. It was a circular room into which they stepped, the very tip of a tower, and a wireless telegraph apparatus was there in operation. "How is it working?" promptly questioned Roque of an operator who was off his turn, and relieved of his headgear. The man jumped to his feet, all attention, and replied: "There's been hardly a break for an hour, sir." Here was one of the hidden intelligence stations that accounted in part for Roque's ability to get searching and quick information. That he should initiate the boys into his particular secret service methods indicated a determination that they should never get away from him. As Billy said to Henri at a chance moment, "He thinks we are booked for a life job as his air chauffeurs." They were not aware as yet that in the extensive grounds, housed at the water's edge, was the seaplane in which they had recently traveled so far, and in addition a big biplane and two monoplanes were in hangars ready for service. Also the most speedy of steam launches rested at the private wharf. Roque was a recognized genius, like every cog in the German wheel, absolutely thorough in his methods, and the means placed at his disposal were practically limitless. Billy and Henri had climbed into the steep embrasure of a tower window and were enjoying the magnificent view spread out before them. "How about my imagination now?" Henri was recalling exciting incidents in the hotel. "Didn't I get the figure of the sandy man as a spotter?"