At nine o'clock the following morning five men grouped in McCarthy's office, talking earnestly. Darrow and Jack Warford had been the first to arrive. McCarthy did not seem surprised to see them; nor did he greet them with belligerence.

"Well?" he demanded.

"Well?" repeated Darrow, sinking gracefully to one corner of the table. "You're an old fool, McCarthy. What good did you think it would do you to arrest me?"

"I intended to sweat you," confessed the boss frankly, "but I was too busy."

"Sweat me, eh?" demanded Darrow, with some amusement. "So you decided not to, did you—hence the lack of enthusiasm on the part of the police in effecting my recapture. You didn't imagine I caused all this, did you?"

"I don't know," growled McCarthy. "But if you, or the other fellow, or whoever or whatever it is, think you can bluff me out, you or he or it's left! That's all!"

"So you've been getting more wireless, have you?" surmised Darrow.

McCarthy cast a surly glance toward Jack, whom previously he had ignored.

"Yes," he admitted grudgingly.

Darrow held out his hand. After a moment's hesitation McCarthy thrust forward a single yellow paper, and Darrow read aloud in spite of the boss' warning gesture:

"McCarthy: The sign has been sent you and sent your people. You are stubborn, but it shall not avail you. You must go; and within twenty-four hours. It will not avail you unless you go. The Celtic leaves to-morrow at noon. You must go on that ship. I shall know whether or not you obey me. Once more I shall warn you; one more sign shall I send. Then I shall strike!"

"He's getting garrulous," remarked Darrow reflectively; "but he's relieved my mind. You'd better go."

"Go!" cried McCarthy, half starting to his feet. "Not on your life!"

Darrow surveyed him calmly.

"You're getting rattled," said he, "and it doesn't pay you particularly to try to bluff me. A jack-rabbit of average firmness could stampede you in your present state of mind."

"You think so?" sneered McCarthy.

"I know so. And you're quite right. If you attempt the game too long, he'll destroy you."

"How?" demanded McCarthy.

"Take my word for it, he can do it!" replied Darrow.

McCarthy ruminated, drumming his thick fingers on the desk.

"Find him," said he, at last.

"I intend to," replied Darrow.

"That'll be all right about your friend's job," conceded McCarthy, with a nod toward Jack.

"I fancy you won't have anything to do with it," returned Darrow pleasantly.

At this moment the door opened and Hallowell entered. He nodded to Darrow, and greeted McCarthy.

"Nothing for you," growled the latter.

Darrow glanced at his watch.

"He will have in about five minutes," said he to the reporter.

The fifth member of the party now entered in the person of Simmons, the United Wireless operator. On seeing the number gathered in McCarthy's office he came to a halt.

Darrow immediately detached himself from the group and approached this man.

"Anything new?" he inquired in a low voice.

Simmons glanced toward McCarthy.

"New about what?" he demanded stolidly.

"Any more messages from our mysterious friend out in the ether to our equally mysterious friend at the desk?"

"I don't know what you mean."

Darrow surveyed him reflectively.

"This is a pretty big story," he said at last, "and affects a lot of people. If you really haven't leaked—well, he"—with a jerk of his head toward McCarthy—"must bribe high, or have a strangle hold on you for fair."

He looked around to see the boss' eye fixed intently on him, smiled pleasantly, and moved to one side. Simmons stepped forward, handed McCarthy a paper, and went out. The boss read the message slowly, and turned a little pale. After a moment or so he surreptitiously drew out his watch. Percy Darrow smiled. He, too, held his watch in his hand.

"Thirty seconds more—about," he remarked pleasantly. The boss looked up startled. The last thing he saw was the faintly smiling, triumphant face of the young scientist. Then absolute blackness fell on him.

For several seconds astonishment held the inmates of the room chained to their places; and for that space of time no sound broke the deathly stillness. Then Percy Darrow spoke, in his natural voice.

"Well, Jack," he remarked, "it worked out, to a second, almost. Now I'm certain."

As though this breaking of the silence had released a force hitherto held in repression, the room filled with tumult and clamor, with crashing, banging and scurrying of heavy bodies. A final concussion shook the air, and then, again abruptly, silence fell.

"Say!" Hallowell's voice spoke up, a trifle uncertainly. "I'll stand for most any kind of a dark seance, but this particular spook business is getting on my nerves. Are you there, Darrow?"

"Yes, I'm here," answered the scientist.

"Well, can you explain that phenomenon?"

"That," drawled Darrow, a slight note of laughter in his voice, "was that extraordinary upheaval of natural forces known as Brother McCarthy going away from here—hastily."

Jack chuckled.

"He hit me on the way out," remarked that young man. "I'll testify he was a solid spook."

The reporter was methodically striking match after match, but without result. After a moment the acrid smell of burning woolen rose in the air.

"Are you dropping those matches?" asked Darrow.

"Sure; they're no good."

"Well, they're good enough to burn holes in McCarthy's rugs. Stamp around a little to put them out; and quit it."

"What next; and how long?" asked Jack. "What is it? Have we gone blind, or is it a total eclipse, or what?"

"I don't know how long," came back Darrow's voice calmly. "Next we will get out of the building. I want to make some observations. Get hold of my hand; we'll have to grope our way out."

"If we could only get a light," muttered Hallowell.

"You can't," stated Darrow.

They felt their way down the ten flights of stairs like blind men. A few inmates of the building they jostled, or passed, or picked up on the way.

"This settles it," one remarked profanely. "My lease quits. They can sue and be damned. I decline to have anything more to do with any freak-lined skyscraper of this description."

In the lower corridors Darrow halted them.

"Here's another thing," said he: "if I'm right, we should run out of this just eleven feet beyond the last elevator cage."

He felt his way along the grill, made four paces forward, and uttered a little cry of satisfaction. The two men followed him blindly. As though stepping from one room to another they emerged into glaring daylight!

Both involuntarily looked back. The darkness hung there like a curtain, just inside the outer walls of the building. Already a crowd had gathered to observe this new and strange phenomenon of the now celebrated Atlas Building. It was a curious and a facetious crowd, but not awestricken, as it had been at the first manifestations of this freakish upset of natural forces.

A man observing the flight of an aeroplane for the first time loses his sense of strangeness inside of a few minutes; and yet flying has been since the days of Icarus considered one of the impossible achievements. So the general public of Manhattan were becoming accustomed to reversals of form in the affairs of the physical world. The frivolous majority, having discovered nothing to be apprehended from the phenomena save a few hours' helplessness of a sort, and much to be gained through the savor of novelty, were inclined to an amused or irritated attitude, depending on the extent to which its occupations were interfered with. The minority took to religious meetings and interpretations.

Darrow's exit, and that of his companions, was greeted uproariously.

"'Please go 'way an' let me sleep!'" sang one, at the blinking men.

"Here's another!" shrilled a gamin. "Get up! The porter wants to make up your berth!"

Several of the crowd, pending the usual arrival of the police to clear the corridor, had ventured through the wide portals, and were experimenting with this strange palpable quality of darkness. One or two popped inside the curtain, but emerged quickly, looking a little scared.

A bright youth made the discovery that if one lighted a match and stepped within the blackness, the match was immediately extinguished, but that upon emerging into daylight the flame came up again. Some one happened along with a plumber's gasoline torch. Immediately this was lighted and the experiment repeated. The bearer of the torch, astonished at the instant extinguishment of the flame, felt with his hand to see what could be the matter. Instantly he uttered a yelp of pain, and leaped outside, displaying a badly burned palm.

"There wasn't no flame; I swear it!" he explained excitedly, "but she burned, just the same!" He rushed about from one to another, displaying his injured palm to whoever would look.

Darrow paid little attention to this gathering crowd. First of all, he scanned a paper he held in his hand; then plunged back again into the blackness.

Jack Warford and Hallowell, left together, hesitated uncertainly.

"He'll be back," the reporter decided finally, "and he's the man to tie to."

While waiting, he proceeded to pick up what information he could from the bystanders. It seemed that the first intimation of anything wrong was followed very shortly by the emergence of McCarthy, disheveled, hatless, staring, gasping. The boss had stumbled into the street, hesitated, then started south on a run. Before any one could stop him, he had turned a corner and disappeared. The excitement at the Atlas Building had distracted attention from him. Nobody wondered at his getting rattled and running away. The few tenants remaining in the building had stumbled forth, vowing never to return to such a—assorted adjectives—building. That was all there seemed to be to say.

In the meantime the crowd had increased from a few hundred to thousands. Police appeared. The corridors were cleared of all but a few. Among these were Hallowell and Jack Warford; the former as a reporter, the latter as the reporter's companion. Doctor Knox and Professor Eldridge arrived shortly. After a time Darrow reappeared, sauntering quite calmly from the pall of darkness, as though emerging from behind a velvet curtain.