"What are we going to do to-night?" asked Jim.

Dennis looked quizzically at his big friend. Jim was pacing restlessly up and down the living room of the bachelor apartment, puffing jerkily at his eternal pipe. Dennis knew the symptoms. Though he hadn't seen Jim for over a year, he remembered his characteristics well enough.

Some men seem designed only for action. They are out of step with the modern era. They should have lived centuries ago when the world was more a place of physical, and less of purely mental, rivalry.

Jim was of this sort. Each time he returned from some trip—to Siberia, the Congo, the mountainous wilderness of the Caucasus—he was going to settle down and stop hopping about the globe from one little-known and dangerous spot to another. Each time, in a matter of weeks, he grew restless again, spoiling for action. Then came another impulsive journey.

He was spoiling for action now. He didn't really care what happened that evening, what was planned. His question was simply a bored protest at a too tame existence—a wistful hope that Denny might lighten his boredom, somehow.

"What are we going to do to-night?"

"Well," said Denny solemnly, "Mrs. Van Raggan is giving a reception this evening. We might go there and meet all the Best People. There is a lecture on the esthetics of modern art at Philamo Hall. Or we can see a talkie—"

"My Lord!" fumed Jim. Then: "Kidding aside, can't you dig up something interesting?"

"Kidding aside," said Dennis, in a different tone, "I have dug up something interesting. We're going to visit a friend of mine, Matthew Breen. A young man, still unknown, who, in my opinion, is one of our greatest physicists. Matt is a kind of savage, so he may take to you. If he does—and if he's feeling in a good humor—he may show you some laboratory stunts that will afford you plenty of distraction. Come along—you're wearing out my rugs with your infernal pacing up and down!"

Matt Breen's place was in a ratty part of the poorer outskirts of town; and his laboratory was housed by what had once been a barn. But place and surroundings were forgotten at sight of the owner's face.

Huge and gaunt, with unblinking, frosty gray eyes, looking more like an arctic explorer than a man of science, Matt towered over the average man and carelessly dominated any assembly by sheer force of mentality. He even towered a little over big Jim Holden now, as he absently shook hands with him.

"Come in, come in," he said, his voice vague. And to Denny: "I'm busy as the devil, but you can watch over my shoulder if you want to. Got something new on. Great thing—though I don't think it'll have any practical meaning."

The two padded after him along a dusty hallway, up a flight of stairs that was little more than a ladder, and into the cavernous loft of the old barn which had been transformed into a laboratory.

Jim drew Denny aside a pace or two. "He says he's got something new. Isn't he afraid to show it to a stranger like me?"

"Afraid? Why should he be?"

"Well, ideas do get stolen now and then, you know."

Denny smiled. "When Matt gets hold of something new, you can be sure the discovery isn't a new kind of can-opener or patent towel-rack that can be 'stolen.' His ideas are safe for the simple reason that there probably aren't more than four other scientists on earth capable of even dimly comprehending them. All you and I can do—whatever this may turn out to be—is to watch and marvel."

Matt, meanwhile, had lumbered with awkward grace to a great wooden pedestal. Cupping down over this was a glass bell, about eight feet high, suspended from the roof.

Around the base of the pedestal was a ring of big lamp-affairs, that looked like a bank of flood-lights. The only difference was that where flood-lights would have had regular glass lenses to transmit light beams, these had thin plates of lead across the openings. Thick copper conduits branched to each from a big dynamo.

Matt reached into a welter of odds and ends on a bench, and picked up a tube. Rather like an ordinary electric light bulb, it looked, save that there were no filaments in the thin glass shell. Where filaments should have been there was a thin cylinder of bluish-gray metal.

"Element number eighty-five," said Matt in his deep, abstracted voice, pointing at the bluish cylinder. "Located it about a year ago. Last of the missing elements. Does strange tricks when subjected to heavy electric current. In each of those things that look like searchlights is one of these bulbs."

He laid down the extra tube, turned toward a door in the near wall, then turned back to his silent guests again. Apparently he felt they were due a little more enlightenment.

"Eighty-five isn't nearly as radioactive as the elements akin to it," he said. Satisfied that he had now explained everything, he started again toward the door.

As he neared it, Dennis and Jim heard a throaty growling, and a vicious scratching on the wooden panels. And as Matt opened the door a big mongrel dog leaped savagely at him!

Calmly, Matt caught the brute by the throat and held it away from him at arm's length, seeming hardly to be aware of its eighty-odd pounds of struggling weight. Into Jim's eyes crept a glint of admiration. It was a feat of strength as well as of animal management; and, himself proficient in both, Jim could accord tribute where it was due.

"You came just as I was about to try an experiment on the highest form of life I've yet exposed to my new rays," he said, striding easily toward the glass bell with the savage hound. "It's worked all right with frogs and snakes—but will it work with more complex creatures? Mammalian creatures? That's a question."

Denny forbore to ask him what It did, how It worked, what the devil It was, anyway. From his own experience he knew that the abstraction of an experimenter insulates him from every outside contact. Matt, he realized, was probably making a great effort to remain aware that they were there in the laboratory at all; probably thought he had explained in great detail his new device and its powers.

Vaguely wrapped in his fog of concentration, Matt thrust the snarling dog under the bell, which he lowered quickly till it rested on the pedestal-floor and ringed the dog with a wall of glass behind which it barked and growled soundlessly.

Completely preoccupied again, Matt went to a big switch and threw it. The dynamo hummed, raised its pitch to a high, almost intolerable keening note. The ring of pseudo-searchlights seemed in an ominous sort of way to spring into life. The impression must have been entirely imaginary; actually the projectors didn't move in the slightest, didn't even vibrate. Yet the conviction persisted in the minds of both Jim and Dennis that some black, invisible force was pouring down those conduits, to be sifted, diffused, and hurled through the lead lenses at the dog in the bell.

Thrilled to the core, not having the faintest idea what it was they were about to see, but convinced that it must surely be of stupendous import, the two stared unwinkingly at the furious hound. Matt was staring, too; but his glance was almost casual, and was concentrated more on the glass of the bell than on the experimental object.

The reason for the direction of his gaze almost immediately became apparent. And as the reason was disclosed, Dennis and Jim exclaimed aloud in disappointment—at the same time, so intense was their nameless suspense, not knowing they had opened their mouths. It appeared that for yet a little while they were to remain in ignorance of the precise meaning of the experiment.

The glass of the bell was clouding. A swirling, milky vapor, not unlike fog, was filling the bell from top to bottom.

The dog, rapidly being hidden from sight by the gathering mist, suddenly stopped its antics and stood still in the center of the bell as though overcome by surprise and indecision. Motionless, staring vacantly, it stood there for an instant—then was concealed completely by the rolling vapor.

But just before it disappeared, Jim turned to Denny in astonishment, to see if Denny had observed what he had; namely, that the fog seemed not to be gathering from the air penned up in the bell, but in some strange and rather awful way to be exuding from the body of the dog itself!

The two stared back at the bell again, neither one sure he had been right in his impression. But now the glass was entirely opaque. So thick was the vapor within that it seemed on the point of turning to a liquid. Inside, swathed in the secrecy of the fleecy folds of mist—what was happening to the dog? The two men could only guess.

Matt glanced up at an electric clock with an oversized second hand. His fingers moved nervously on the switch, then threw it to cut contact. The dynamo keened its dying note. A silence so tense that it hurt filled the great laboratory.

All eyes were glued on the bell.

The thick vapor that had been swirling and crowding as if to force itself through the glass, grew less restive in motion. Then it began to rise, ever more slowly, toward the top.

More and more compactly it packed itself into the arched glass dome, the top layers finally resembling nothing so much as cloudy beef gelatin. And now these top layers were solidifying, clinging to the glass.

Meanwhile, the bottom line of the vapor was slowly rising, an inch at a time, like a shimmering curtain being raised from a stage floor. At last ten inches showed between the pedestal and the swaying bottom of the almost liquid vapor. Jim and Denny stooped to peer under the blanket of cloud. The dog! In what way had it been affected?

Again they exclaimed aloud, involuntarily, unconsciously.

There was no dog to be seen.

With about fourteen clear inches now exposed, they looked a second time, more intently. But their first glance had been right. The dog was gone from the bell. Utterly and completely vanished! Or so, at least, they thought at the moment.

The rising and solidifying process of the vapor went on, while Dennis and Jim stood, almost incapable of movement, and watched to see what Breen was going to do next.

His next move came in about four minutes, when the crowding vapor had at last completely come to rest at the top of the dome like a deposit of opaque jelly. He stepped to the windlass that raised the bell, and turned the handle.

Immediately the two watchers strode impulsively toward the exposed pedestal floor.

"Wait a minute," commanded the scientist, his eyes sparkling with almost ferocious intensity. The two stopped. "You might step on it," he added, amazingly.

He caught up a common glass water tumbler, and cautiously moved to the edge of the platform. "It may be dead, of course," he muttered. "But I might as well be prepared."

Wonderingly, Jim and Dennis saw that he was intently searching every square inch of the pedestal flooring. Then they saw him crawl, like a stalking cat, toward a portion near the center—saw him clap the tumbler, upside down, over some unseen thing....

"Got him!" came Matt's deep, fuzzy voice. "And he isn't dead, either. Not by a long way! Now we'll get a magnifying glass and study him."

Feeling like figures in a dream, Jim and Dennis looked through the lens with their absorbed host.

Capering about under the inverted tumbler, like a four-legged bug—and not a very large bug, either—was an incredible thing. A thing with a soft, furry coat such as no true insect possesses. A thing with tiny, canine jaws, from which hung a panting speck of a tongue like no bug ever had.

"Yes," rumbled Matt, "the specimen is far indeed from being dead. I don't know how long it might exist in so microscopic a state, nor whether it has been seriously deranged, body or brain, by the diminishing process. But at least—it's alive."

"My God!" whispered Dennis. And, his first coherent sentence since the physicist had thrown the switch: "So this—this—is the overgrown brute you put under the bell a few minutes ago! This eighth-of-an-inch thing that is a miniature cartoon of a dog!"

Jim could merely stare from the tumbler and the marvel it walled in, to the man who had worked the miracle, and back to the tumbler again.

Denny sighed. "That thick, jellylike substance in the top of the bell," he said, "what is it?"

"Oh, that." The miracle worker didn't lift his eyes from the tumbler and the very much alive and protesting bit of life it housed. "That's the dog. Rather, it's practically all of the dog save for this small residue of substance that clothes the vital life-spark."

Jim dabbed at his forehead and found it moist with sweat. "But how is it done?" he said shakily.

"With element eighty-five, as I told you," said Breen, most of whose attention was occupied by a new stunt he was trying: he had cut a microscopic sliver of meat off a gnawed bone, and was sliding it under the glass. Would the dog eat? Could it...?

It could, and would! With a mighty bound, that covered all of a quarter of an inch, the tiny thing leaped on the meat and began to gnaw wolfishly at it. The effect was doubly shocking—to see this perfect little creature acting like any regular, full-sized dog, although as tiny as a woman's beauty spot!

"Marvelous stuff, eighty-five," Matt went on. "Any living thing, exposed to the lead-filtered emanations it gives off when disintegrated electrically to precisely the right degree, is reduced indefinitely in size. I could have made that dog as small as a microbe, even sub-visible perhaps, if I chose. Curious.... Maybe the presence of eighty-five in minute quantities on earth is all that has kept every living thing from growing indefinitely, expanding gigantically right off the face of the globe...."

But now Dennis was hardly listening to him. A notion so fantastic, so bizarre that he could not at once grasp it fully, had just struck him.

"Listen," he said at last, his voice so hoarse as to be almost unrecognizable, "listen—can you reverse that process?"

Matt nodded, and pointed to the viscous deposit in the dome of the bell. "The protoplasmic substance is still there. It can be rebuilt, remolded to its original form any time I put the dog back in the bell and let the particles of eighty-five, which are suspended in the vacuum tubes, settle back into their original, inert mass. You see, there is such a close affinity—"

Dennis cut him short almost rudely. It wasn't causes, marvelous though they might be, that he was interested in; it was results.

"Would you dare ... that is ... would you like to try that experiment on a human being?"

Now for once the inventor's entire interest was seized by something outside his immediate work. He stared open-mouthed at Dennis.

"Would I?" he breathed. "Would I like ..." He grunted. "Such a question! No experiment is complete till man, the highest form of all life, has been subjected to it. I'd give anything for the chance!" He sighed explosively. "But of course that's impossible. I could never get anyone to be a subject. And I can't have it tried on myself because I'm the only one able to handle my apparatus in the event that anything goes wrong."

"But—would you try it on a human being if you had a chance?" persisted Denny.

"Hah!"

"And could you reduce a human being in stature as radically as you did the dog? For example, could you make a man ... ant-size?"

Matt nodded vigorously, eyes fairly flaming. "I could make him even smaller."

Dennis stared at Jim. His face was transfigured. He shook with nervous eagerness. And Jim gazed back at Dennis as breathlessly and as tensely.

"Well?" said Dennis at last.

Jim nodded slowly.

"Yes," he said. "Of course."

And in those few words two men were committed to what was perhaps the strangest, most deadly, and surely the most unique, adventure the world has yet known. The improbable had happened. A man who lived but for dangers and extraordinary action, and a man who would have gambled his soul for the scientist's ecstasy of at last learning all about a hidden study—both had seen suddenly open up to them a broad avenue leading to the very pinnacle of their dreams.