"Precisely. Now as to theories of the ultimate cause. Naturally this must have been brought about either by nature or by man. If by nature, it is exceedingly localized, not to say directed. If by man, he must have in some way acquired unprecedented powers over the phenomena of electricity and sound. These he can evidently, at will, either focus, as on the Atlas Building, or diffuse, as over the city. For the moment we will adopt the latter hypothesis."
"That it is a man in possession of extraordinary powers," said Helen, leaning forward in her interest. "Go on."
"We have, completed, only the phenomena of electricity," continued Darrow; "the phenomena of sound remain to be completed. We observe as to that (a)"—he folded back his forefinger—"the Atlas manifestation lasted about nine and a half hours; and (b)"—he folded his middle finger—"the city manifestation was a little less than two hours."
"Yes," cried Jack, "but then this second—"
"One minute," interrupted Darrow; "let me finish. Now, let us place ourselves in the position of a man possessed of a new toy, or a new power which he has never tried out! What would he do?"
"Try it out," said Jack.
"Certainly; try it out to the limit, to see just what it could do in different circumstances. Now, take the lapses of time I have mentioned, and assume, for the sake of argument, that these powers are limited."
"Just how do you mean—limited?" asked Helen.
"I mean exhaustible, like a watering-pot. You can water just so much, and then you have to go back and fill up again. In that case, we can suppose this man's stream will last nine hours and a half when he dribbles it down on one spot, like the Atlas Building; but it will empty itself in about two hours when he turns her upside down over a whole city. There remains only the length of time necessary to refill the water-pot to round out our hypothesis. That is something more than nine hours and something less than fifteen."
"How do you get those figures?" demanded Jack.