Percy Darrow in the police station, where he had been assigned an unused office instead of a cell, amused himself reading the newspapers, of which he caused to be brought in a full supply. Theories had begun to claim their share of the space which, up to now, the fact stories had completely monopolized. Darrow, his feet up, a cigarette depending from one corner of his mouth, read them through to the end. Then he indulged the white walls of his little apartment with one of his slow smiles. The simplest of the theories had to do with comets. The most elaborate traced out an analogy between the "blind spot" in vision and a "point of rest" in physical manifestations—this "point of rest" had just now happened to drift to a crowded center, and so became manifest.

"Ingenious but fantastic youth," was Percy Darrow's tribute to the author,
Professor Eldridge of the university.

The "human-interest" stories of both the evening before and those in the extras describing the latest freak in the Atlas Building, Darrow passed over with barely a glance. But certain figures he copied carefully into his notebook. When he had found all of these, and had transcribed them, they appeared about as follows:

Atlas—Wednesday, 5:25. 3:00 (about): 9 hr. 35 min.

General—Thursday, 6:00. 7:56 (exact): 1 hr. 56 min.

Atlas—Friday, 10:10. 10:48 (exact): 38 min.

On the basis of these latter figures he made some calculations which, when finished, he looked on with doubtful satisfaction.

"Need more statistics," said he to himself, "before I can pose as a prophet. Just now I'm merely a guesser."

By now it was afternoon. An official came to announce visitors, and a moment later Helen and her brother came in. As Percy's case was merely one of detention, or for some other obscurer reason, known only to those who took their orders from McCarthy, the three were left alone to their own devices.

At the sight of Helen's trim tailor-clad figure Percy's expression brightened to what, in his case, might almost be called animation. He swept aside the accumulation of papers, and made room for both. After the first greetings and exclamations, Helen demanded to know particulars and prospects.

"All right, I'll tell you," agreed Darrow. "I'm thought out; and I want to hear it myself."

Jack looked about him uneasily.

"Is it wise to talk here?" he asked. "I don't doubt they have arrangements for overhearing anything that is said."

"I don't think they care what we say," observed Darrow. "They are merely detaining me on some excuse or another that I haven't even taken the trouble to inquire about."

"That must astonish them some," said Jack.

"And if they do overhear, I don't much care. Now," said he, turning to Helen, "we have here three strange happenings comprising two phenomena—the cutting off of the electricity, first in the Atlas Building, second in the city at large; and the cutting off of sound in the Atlas. Although we are, of course, not justified in generalizing from one instance, what would you think by analogy would be the next thing to expect?"

"That sound would be cut off in the city," said Helen; "but Jack has already delivered me your warning or advice," she added.

"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.

"The Unknown is anxious, after the Atlas success, to try out his discovery on the larger scale. He will naturally do so at the first opportunity after his water-pot is refilled. But he wishes to do so at the first effective opportunity. What is the most effective moment? The rush hours. What are the rush hours? From eight to ten, and at six. Since he did not pull off his show in the morning, we are fairly justified in concluding, tentatively, that the water-pot was not full by then, and, as the Atlas phenomena subsided at three of the morning before, the inference is obvious."

"But isn't the most effective time at night, anyway, on account of the lights?" asked Jack.

"Good boy!" approved Darrow. "He might have waited for that. But the city-wide phenomena ceased at eight the night before; and the Atlas sound phenomena did not occur until ten the next morning—fourteen hours. Now, the most effective time to scare McCarthy was any time after nine. McCarthy arrives as the clock strikes."

Jack shook his head.

"Oh, it's not proof; it's idle hypothesis," admitted Darrow. "We shall have to test it. But let's go on with it, anyway, and see how it works out."

"What's McCarthy got to do with it?" demanded Helen.

"That's so, you aren't in touch there." Darrow sketched briefly the situation as it affected the boss. Helen's eyes were shining with interest.

"Now," continued Darrow, "having tried out his new power to the limit, our friend would begin to use it only as he needed it. There is now no reason to empty the water-pot entirely. All he wanted to do this morning was to scare McCarthy, and impress the public. He did that in thirty-eight minutes. On the basis of fourteen hours to fill the water-pot, it is evident that he would be rehabilitated, ready for business, in an hour. Therefore, all he is waiting for now is the most effective moment to try out his city-wide experiment of silence. I imagine that will be about six."

"Sounds reasonable," admitted Jack.

"Reasonable! It's certain!" cried Helen.

Darrow smiled. "No, only a wild hypothesis."

"It'll scare people to death," observed Jack.

"They're scared already; and they're somewhat prepared by the performance this morning. Besides, I don't see yet that human agency is suspected."

"Don't you think you'd better warn people what is going to happen, and tell them there's nothing to be frightened of?" pleaded Helen.

"No," said Darrow, "I do not. It would confuse the phenomena, and they must be unconfused in order that I can either prove or disprove my hypothesis. If this lasts about two hours, the fact will go far to prove me right. If the next manifestation comes at about ten the next morning, we shall have established a periodicity, at least. But if the man realizes that his existence is suspected, he will purposely vary in order to mix me up."

"The next manifestation!" cried Helen. "Then you think they will continue—"

"Why not," smiled Darrow, "until he has scared McCarthy out?"

"Which will it be next time, do you think?"

"Whatever happens, don't be frightened," said Darrow enigmatically.

"It seems to me there is something absurd about all this," said Helen. "A man with such a discovery, such powers, using them in such a manner, for such a petty purpose!"

"He is, of course, crazy," Darrow said quietly; "the methodical logical lunatic—the most dangerous sort."

"What is it he has discovered?" asked Jack.

"I do not know, yet."

"But you suspect?"

Darrow nodded, but would not explain.

"What will be the outcome?"

"I am going to cut loose from science and guess wildly," said Darrow, after a moment. "To-morrow morning, somewhere about ten, McCarthy will disappear."

"You said that before!" cried Jack.

"Well, I say it again," drawled Darrow.