They fell into the lower hallway, and fought their way to the street, and stood there dazed and staring, a strange, wild-eyed, white-faced, bloody crew. The hurrying avenue stopped to gaze on them curiously, gathering compact in a mob that blocked all traffic. Policemen pushed their way in and began roughly to question--and to question in real audible words. But for the space of a full minute these people stood there staring upward, drinking in the blessed sound that poured in on them lavishly from the life of the street; drinking deep gulps of air, as though air had lacked. Darrow, and with him Jack Warford, had descended more leisurely. Before leaving the building Darrow placed the flat of his hands over his ears, and motioned Jack to do the same. Thus they missed the stunning effect of receiving the world of noise all at once; as a man goes to a bright light from a dark room. Furthermore, Darrow returned several times from the sound to the silence, trying to determine where the line of demarcation was drawn. Then, motioning to Jack, he began methodically to make his way through the crowd. This proved to be by no means an easy task. Rumors of all sorts were afoot. Some bold spirits were testing a new sensation by venturing into the corridor of the building. The police were undecided as to what should be done. One or two reporters were already at hand, investigating. McCarthy, his assurance returned, was conversing earnestly with a police captain. Percy Darrow, closely followed by Jack, managed to worm his way through the crowd, and finally debouched on Broadway. "What was it? What struck us?" demanded Jack. "Do you know?" "I can guess; in essence," said Percy. "I was pretty sure after last evening's trouble; but this underscores it, proves it. Also, it opens the way." "What do you mean?" "Along the lines of these phenomena there are two more things possible. Possible, I say. They might be called certain, were we dealing only with theory; but there is still some doubt how the practical side of it may work out." "I suppose you know what you're talking about," said Jack resignedly. "I don't." "You don't need to, yet. But here's what I mean. If my theory is correct, we are likely to be surprised still further." Jack ruminated; then his engaging young face lighted up with a smile. "All right," said he; "I'm enlisted for the war. What have you got to do with it?" "I'll explain this much," said Darrow; "more I'll not tell at present, even to you. If one breath should get out that any one suspected--well, this is a man-hunt." "Who's the man?" "An enemy of McCarthy." "Whom you are going to find for him?" "Perhaps." "And you were putting up that job for me as part of your pay!" Percy Darrow smiled slowly. "As all of my pay--from McCarthy," said he. "I was just bedeviling him." Jack Warford started to say something, but the scientist cut him short.