He was relieved to find Felix Van Loon sitting on the doorstep waiting for him. "Won't have to run the gauntlet of eyes in the wall and submit my skeleton for inspection this time," he whispered to himself. "Come on in and have a cup of coffee with me before we get down to work," the other boy welcomed. "Be glad to," Johnny answered. "Watch!" Felix said a moment later. He pressed a button, then shot a wooden panel to one side, revealing a recess. In that dark hole in the wall things began to happen. Two electric coils began to light up. At the same time Johnny noted with a start that two red eyes were gleaming from the darkest corner. "Eyes," Felix murmured. "They'll do your work if you let them." Felix made no further comment. Johnny did not feel free to ask questions about the riddle of the "Eye." Dropping into a chair, Felix stared for a full two minutes at a crack in the floor. Then with a start he sprang to his feet, threw open a second panel and proceeded to draw forth a steaming pot of coffee and a plate of toast. Johnny recalled the professor's remarks regarding the "Eye" but said nothing. "It's a queer place," he told himself. As if reading his thoughts, Felix put down his cup. "Father's what they call an electrical wizard," he said. "He does things no one dreams of. Enjoys it a lot, he does. So do I. But Father has a deep purpose in it all, thinks electricity may help to save the race; anyway that's what he calls it." Once more he lapsed into silence. Johnny searched the dark corners of the room for peering eyes, but could find none. "Through?" Felix asked quite suddenly. "All right then, let's be on our way." He strode across the room to catch up a kit of tools. A moment more and they were in the street marching south. They had passed one brownstone building and were approaching a second when Felix drew Johnny into a doorway. "Ought to tell you, I guess." His voice was low. "Sort of warn you in case anything happens. Bit irregular, the thing we are about to do. If it frightens you after I've told you, just say so. Every fellow has a right! "You see," he got a fresh start, "Father was once in the secret service. He became interested at that time in working out devices for trapping criminals. And they _should_ be trapped." His voice rose. "Ninety per cent of all crimes are committed by men who never work. Professional criminals, they make life unsafe for everyone. But Father doesn't trap 'em. He just works out the traps. He's too much interested in making things to think much about using them himself. See that brick place, second door over?" His voice dropped. "Some queer ones live there--a tall one and a short one." "Tall one and a short--! I--" "Not much time." Felix held up a hand. "Sleep late, those two, but not too late. Got to get in and do some things before they come downstairs.