Condemned of mixing in the battle of wits between the grim Roque and his strongest wily rival from over the sea, and it were better that the young aviators had tumbled from their aëroplane during the last high flight. But those who traveled in spirit with Billy Barry, the boy from Bangor, Maine, U. S. A., and his plucky teammate, Henri Trouville, in France and Belgium, can assure that it is no easy task to catch this pair napping. The courage tempered by that first and continuous baptism of fire was good steel for any emergency. Roque owned to himself that his quickfire had failed to get results. His informant, himself just returning from a secret mission on hostile soil, had noted the movements of the sailor suspect on the aviation exhibit day, and also the attitude of Henri at the moment when the message was passed. But of the message itself, the reporting agent could have no knowledge. He was not near enough to detect a trick so deftly done. Roque and Ardelle had measured brains many a time and often, but heretofore at long range, and the former had never seen the latter in person. Had such been the case, the French agent's invasion of the empire would have ended at Bremen, when these two masters of craft had both been guests at the same time of the same café. Roque's unerring judgment had convinced him after the first question that the boys had no knowledge of the name Ardelle. Their first profession of ignorance was too real to be mere acting. The boys took care that the light that came to them as Roque proceeded did not shine in the direction of the lynx-eyed questioner. The rigid lines in the face of the secret agent relaxed. These boys, after all, had once served him a good turn, with a skill, courage and fidelity far beyond the ordinary, and, perhaps, he was not sorry that he had apparently found them guiltless. "Now, young sirs," said Roque, resuming the manner of the merchant, "I have another little journey in store for you. I don't know for certain that it will prove as exciting as the last jaunt we took together, when you located a shipload of guns for me, but maybe so, maybe so. "After we have made our excuses to the lieutenant," he continued, "we will go over to my humble home in the city, where I have some new clothes for you. I do not think you are warlike enough to want to travel in any sort of uniform, especially with a simple tradesman like myself." It was on the tip of Billy's tongue to ask Roque why he kept up that sort of talk with those who knew him without his mask, and when there was no purpose to be served, but Billy concluded that he had better let well enough alone. A roomy carryall was in waiting at the further end of the parade ground, toward which the merry old merchant led his young friends, with a hand under the elbows of both. It was pardonable for the aviation lieutenant to grin when the trio were passing, after making their excuses.