plastic. Over that would go a casing to keep them from expanding or stretching. It ought to be distinctively different from a magnet.

It was an extremely long and utterly tedious job. He knew what he was doing, but he had doubts about the why. As he worked, though, he wrestled out a detailed theory. Discoverers often work like that. It was said that Columbus didn't know where he was going when he started out, didn't know where he was when he got there, and didn't know where he'd been when he got back. The history of the discovery of the triode tube has points of similarity. Burke had begun with a device which destroyed itself when turned on, developed the idea into a device which swelled to uselessness when energized, and now hoped that it would turn out at the third try to be something the textbooks said was impossible.

Outside the construction shed, the world went about its business. While Burke worked on through the Sunday noon hour, a Japanese radar telescope aimed at the night sky and made six successive position-findings on the source of the space signals. When sunset found him laboring doggedly at a metal lathe, Croydon made eight. American radar telescopes had made others. Carefully computed, the observations added up to the discovery of an independent motion of the signal source. It moved against the stars as if it were a solar-system body with an orbit in the asteroid belt some three hundred sixty million miles from the sun—as compared to Earth's ninety-two million.

At midnight on Sunday, while Burke painstakingly made micrometric examination of the triple magnet-core, Harvard Observatory reported that there should be a very minor asteroid at the spot in space from which the signals came.

The coincidental asteroid was known as Schull's object. It was listed as M-387 in the catalogs. It had been discovered in 1913, was a very minor celestial body, had an estimated greatest diameter of less than two miles, and its brightness had been noticed to vary, suggesting that it was of irregular shape. It was too insignificant to have been kept under constant observation, but the signals from space appeared definitely to originate from its position.

An hour after midnight, Eastern Standard time, Palomar detected the infinitesimal speck of light which was Schull's object at exactly the place the radar telescopes insisted was the signal source. Satellite-watching stations now monitored the cryptic signals around the clock, and radar telescopes began to sweep space for possible answers to the space broadcast. There was an uncomfortable possibility that the transmitter might not be signaling Earth, after all, but a fellow mystery of space—an associate or a sister-ship.

More data turned up. M.I.T. made examination of the signals themselves. Timed, the intervals between notes varied as if keyed by something alive. But successive broadcasts were identical to microseconds. The conclusion was that the original broadcast had been set up by hand, as it were, but that all were now transmitted mechanically—automatically—by a robot transmitter.

It was Monday morning when Burke completed the last turn of the last winding of his three-element pseudo-magnet. There are many things which become something else when they change in degree. Electromagnetic radiation may be long radio waves or radiant heat or yellow light or ultraviolet or X-rays, or who knows what, according to its frequency. It is different things with different properties at different wavelengths. Burke believed that his cores and windings were something other than magnets because the "flux" they produced was of a different intensity. He did not believe it to be magnetism.

At nine o'clock Monday morning, he was clumsy from pure, weariness when he began to fit the outer case on the thing he'd worked so long to complete. The hand-weapon in his dream undoubtedly flung bullets through a rifled bore penetrating the very center of the multiple core. The design of the hand-weapon ruled out any possibility of a considerable recoil. It wasn't built to allow the hand to take a recoil. So there must be no recoil. On that basis, Burke had made what finally amounted to a thick rod some six inches long and two in diameter. With the casing in place, it was absolutely solid. There was no play for the windings to expand into. He blinked at it. Common sense said he ought to put it aside and test it when his mind was not nearly numb from fatigue.

Then Sandy came into the constructions shed, looking for him. She'd arrived for work and seen his car outside the shed. Her expression indicated several things: a certain uneasiness, and some embarrassment, and more than a little indignation. When she saw him unshaven and wobbly with weariness, she protested.

"Joe! You've been working since Heaven knows when!"

"Since I left you," he admitted. "I got interested."

"You look dreadful!"

"Maybe I'll look worse after I try out this thing I've made. I'm not sure."

"When did you eat last?" she demanded. "And when did you sleep?"

He shrugged tiredly, regarding the thing in his hands. He'd had enough experience contriving new things to know that no theory is right until something that depends on it has been made and works. He tended to be pessimistic. But this time he thought he had it.

"Is this working night and day a part of your reaction to those signals?" asked Sandy unhappily. "If it is—"

"Let's try it," Burke interrupted. "It's something I worked out from the dream. Now I'll find out whether I'm crazy or not—maybe." He drew a deep breath. He had a sudden, deep and corrosive doubt of things which didn't make sense, like space signals and magnets which weren't magnets because they were capable of negative self-induction. "If this shows no sign of working, Sandy...."

"What?"

He didn't answer. He went heavily over to the table where he had storage-battery current available. He plucked a momentary-contact switch out of a drawer and connected it to the wires from the small thing he'd made. Then he hooked on the storage battery.

"Stand back, Sandy," he said tiredly. "We'll see what happens."

He flipped the momentary-contact switch. There was a crash and a roar. The six-inch thing leaped. It grazed Burke's head and drew blood. It flashed across the room, a full thirty feet, and then smashed a water-cooler and imbedded itself in the brick wall beyond. A tool cabinet tottered and crashed to the floor. The storage battery spouted steam, swelled. Burke grabbed Sandy and plunged outside with her as the building filled with vaporized battery acid.

Outside, he put her down and rubbed his nose with his finger.

"That was a surprise," he said with some animation. "Are you all right?"

"You—could have been killed!" she said in a whisper.

"I wasn't," said Burke. "If you're not hurt there's no harm done. It looks like the thing worked! Lucky that was only a millisecond contact! Negative self-induction.... I'll break some windows and come to the office."

He did break windows, from the outside, so air could flow through the building and clear away the battery-acid steam. Sandy watched him anxiously.

"Okay," he said. "I'll come quietly."

He followed her to the office. He was so physically worn out, he tripped on the office step as he went in.

"Tell me the news on the signals," he said. "Still coming in?"

"Yes." She looked at him again, worried. "Joe ... Sit down. Here. What's happened?"

"Nothing except that I'm a genius at second hand. I didn't intend it that way, and maybe it can be covered up, but I've turned out to be sane. So I think, maybe you'd better get another job. Since I'm sane I'll surely go bankrupt and maybe I'll end up in jail. But it's going to be interesting." His head drooped and he jerked it upright. "This is reaction," he said distinctly. "I'm tired. I wanted badly to find out whether I was crazy or not. I found out I haven't been. I'm not so sure I won't be presently." He made a stiff gesture and