"Roy is doubtless correct," said their leader. "We know they have at least three stations and they may have many more. The object of that, of course, is to baffle any wireless man who may be on their track. If we hadn't stumbled on this spy post at Staten Island, we should have been completely blocked ourselves. But we've got something definite to work on now. We've got a definite clue. And sooner or later we will uncover some of their hidden stations. From now on we've got to watch this man on Staten Island as well as listen for messages. I don't see how we are to do it unless we send for more of the boys or move to Staten Island."
When the matter was laid before Chief Flynn he said no more boys were needed. Too many boys in one house would attract attention. So he arranged to transfer the wireless patrol to Staten Island. Living on the slope above the suspected house was a well-to-do but childless couple with a rather large house, who were warm friends of the Chief's; and they readily agreed, as a matter of service to their country, to take the wireless patrol into their home. So a wireless outfit was installed, with a concealed aerial, and the boys found themselves situated even more pleasantly than they had been before.
And it was well that they were pleasantly situated, for though their task was not difficult in one sense, in another it was extremely trying. Six hours a day each boy sat at the wireless listening in. Had it been possible to tune to longer wave lengths and pick up the interesting news with which the air was fairly alive, the task would have been anything but irksome. But to sit hour after hour with their instruments tuned to the short wave lengths used by the German agents and hear nothing, was trying enough. The watch on the spy's nest proved hardly less tedious. From a gable-window in the attic a very fair view could be had of the little house below. Here, on rainy days, a watcher sat during all the hours of daylight; and on other days the sheltering pines hid an observer. But day followed day, night succeeded night, and no message was registered on the wireless instrument nor did anything suspicious occur in the house under surveillance.
Indeed the fact that nothing did occur was in itself suspicious. For there was hardly a sign of life about the house. No man left it in the morning bound for business. No woman emerged from its door to go shopping of an afternoon. For days at a time nobody entered or left the place, excepting the grocer's boy who came with food.
Then one day a motor-car, with its top raised, chugged up the highway and climbed the steep driveway to the house on the cliff. Henry was in the attic gable on watch and he promptly notified his comrades. There was a rush for the third story, and four heads crowded close together as four pairs of eyes sought to identify the make and number of the car. But the name-plate was missing, and the license tag was so dusty that the number could not be read.
"Run down to the pines with this, quick," said Captain Hardy, thrusting his field-glasses into Willie's hand, "and get the number of that car. See if you can tell what make it is and look for distinguishing marks."
Willie scrambled down the slope through the concealing shrubbery and approached the house as near as he dared. But he had hardly reached his station when the driver ran down the steps of the house, sprang to the wheel, and was off at a fast pace. Willie climbed cautiously back to headquarters.
"Did you get its number?" asked his chief.
"No," replied Willie. "It was covered with dust. And I couldn't tell what make of car it was. But I saw the driver and I am sure I have seen him before and the car, too."
"That's not unlikely," said Captain Hardy, "if he lives anywhere near here. We've been here several days now."