"In the first place, as you know," explained Darrow, "his power seems to be limited in certain directions. He apparently can stop vibrations only of certain defined wave-lengths at one time. It may be that he is unable to stop heat vibrations at all." "You'll have to do better than that," growled Curtis. "The rest is faith--on your part," replied Darrow. "For I'll guarantee that even if Monsieur X has this power, I'll stop him before he exercises it." "Guarantee?" inquired Curtis. "There's nothing to prevent my moving to California or Mombassa if I thought myself in any danger here," Darrow pointed out. "It would be very easy for me quietly to warn my friends and quietly do the grand sneak." "True," muttered Curtis, rummaging on his desk for a pipe. "The danger isn't the point--_it's the fear of danger_," said Darrow. Curtis looked up, arresting the operation of crowding the tobacco into the pipe bowl. "Suppose that throughout the length and breadth of this city the idea should be spread broadcast that at any given moment it might be destroyed. Can you imagine the effect?" "Immediate exodus," grinned Curtis. "Immediate is a nice dignified word," he added. "Quite so, and then?" "Eh?" "What in blazes would four million city people without homes or occupations do? Where would they go? What would happen?" "You see what I mean," went on Darrow, after the slight pause necessary to let this sink in. "The fear would bring about a general catastrophe only less serious than the fact itself. It's up to you newspaper men to see that they don't catch this fear. There'll be a hundred letters from foxy boys with just enough logic or imagination to see the possibility of cutting off the furnace; but without imagination enough to get the final effect of telling people about it. Suppress it. Unless I'm mistaken, the affair will be over in a week." Curtis drummed thoughtfully on his desk. "It's got to be done, and it will be done," he said at last. "I'll get to every paper in the city to-night--if it costs us our scoop." "But won't the people who write the letters tell about it, anyway?" asked Jack. "And won't the outside papers have the same stuff?" "Sure," agreed Curtis promptly, "but what isn't in the city press doesn't get to the mass of the public; that's a cinch. There will be some thousands or even tens of thousands who will leave; there'll be rumors a-plenty; there'll be the damnedest row since the Crusades--but the people will stick. I'm taking your word for the danger." "Well, I'm the hostage," Darrow reminded him. "Correct," said Curtis, reaching for the desk telephone. Hallowell followed the visitors to the narrow hall. "Now," said Darrow in parting, "remember what I have said. Don't mention my name nor indicate that there is anywhere an idea that the identity or whereabouts of Monsieur X is by anybody suspected." CHAPTER XV THE MASTER SPEAKS AGAIN