Breckenridge asked caustically, but with an enigmatic smile.

"Think so? I _know_ so!" replied Stevens, positively. "I always did like kids, and they always did like me--we fall for each other like ten thousand bricks falling down a well. Why, a kid--_any_ kid--and I team up just like grace and poise.... What's gnawing on you anyway, to make you turn Cheshire cat all of a sudden? By the looks of that grin I'd say you had swallowed a canary of mine some way or other; but darned if I know that I've lost any," and he stared at his friend suspiciously.

"To borrow your own phrase, Steve, 'You'd be surprised,'" and Breckenridge, though making no effort to conceal his amus.e.m.e.nt, would say no more.

In a few minutes the door opened, and through it there stepped a grizzled four-striper. Almost hidden behind his ma.s.sive form there was a girl, who ran up to Breckenridge and seized both his hands, her eyes sparkling.

"Hi, Breckie, you old darling! I knew that if we both kept after him long enough Dad would let me ride with you sometime. Isn't this _gorgeous_?"

Stevens was glad indeed that the girl's enthusiastic greeting of the pilot was giving him time to recover from his shock, for Director Newton's "little girl, Nadia" was not precisely what he had led himself to expect. Little she might be, particularly when compared with the giant frame of Captain King, or with Steve's own five-feet-eleven of stature and the hundred and ninety pounds of rawhide and whalebone that was his body, but child she certainly was not. Her thick, fair hair, cut in the square bob that was the mode of the moment, indicated that Nature had intended her to be a creamy blonde, but as she turned to be introduced to him, Stevens received another surprise--for she was one of those rare, but exceedingly attractive beings, a natural blonde with brown eyes and black eyebrows. Sun and wind had tanned her satin skin to a smooth and even shade of brown, and every movement of her lithe and supple body bespoke to the discerning mind a rigidly-trained physique.

"Doctor Stevens, you haven't met Miss Newton, I hear," the captain introduced them informally. "All the officers who are not actually tied down at their posts are anxious to do the honors of the vessel, but as I have received direct orders from the owners, I am turning her over to you--you are to show her around."

"Thanks, Captain, I won't mutiny a bit against such an order. I'm mighty glad to know you, Miss Newton."

"I've heard a lot about you, Doctor. Dad and Breckie here are always talking about the Big Three--what you have done and what you are going to do. I want to meet Doctor Brandon and Doctor Westfall, too," and her hand met his in a firm and friendly clasp. She turned to the captain, and Stevens, noticing that the pilot, with a quizzical expression, was about to say something, silenced him with a fierce aside.

"Clam it, ape, or I'll climb up you like a squirrel!" he hissed, and the grinning Breckenridge nodded a.s.sent to this demand for silence concerning children and nursemaids.

"Since you've never been out, Miss Newton, you'll want to see the whole works," Stevens addressed the girl. "Where do you want to begin? Shall we start at the top and work down?"

"All right with me," she agreed, and fell into step beside him. She was dressed in dove-gray from head to foot--toque, blouse, breeches, heavy stockings, and shoes were of the one shade of smooth, l.u.s.trous silk; and as they strolled together down the pa.s.sage-way, the effortless ease and perfect poise of her carriage called aloud to every hard-schooled fibre of his own highly-trained being.

"We're a lot alike you and I--do you know it?" he asked, abruptly and unconventionally.

"Yes, I've felt it, too," she replied frankly, and studied him without affectation. "It has just come to me what it is. We're both in fine condition and in hard training. You're an athlete of some kind, and I'm sure you're a star--I ought to recognize you, but I'm ashamed to say I don't. What do you do?"

"Swim."

"Oh, of course--Stevens, the great Olympic high and fancy diver! I would _never_ have connected our own Doctor Stevens, the eminent mathematical physicist, with the King of the Springboard. Say, ever since I quit being afraid of the water I've had a yen to do that two-and-a-half twist of yours, but I never met anybody who knew it well enough to teach it to me, and I've almost broken my back forty times trying to learn it alone!"

"I've got you, now, too--American and British Womens' golf champion.

Shake!" and the two shook hands vigorously, in mutual congratulation.

"Tell you what--I'll give you some pointers on diving, and you can show me how to make a golf ball behave. Next to Norman Brandon, I've got the most vicious hook in captivity--and Norm can't help himself. He's left-handed, you know, and, being a southpaw, he's naturally wild. He slices all his woods and hooks all his irons. I'm consistent, anyway--I hook everything, even my putts."

"It's a bargain! What do you shoot?"

"Pretty dubby. Usually in the middle eighties--none of us play much, being out in s.p.a.ce most of the time, you know--sometimes, when my hook is going particularly well, I go up into the nineties."

"We'll lick that hook," she promised, as they entered an elevator and were borne upward, toward the prow of the great interplanetary cruiser.

CHAPTER II

----But Does Not Arrive

"All out--we climb the rest of the way on foot," Stevens told his companion, as the elevator stopped at the uppermost pa.s.senger floor.

They walked across the small circular hall and the guard on duty came to attention and saluted as they approached him.

"I have orders to pa.s.s you and Miss Newton, sir. Do you know all the combinations?"

"I know this good old tub better than the men that built her--I helped calculate her," Stevens replied, as he stepped up to an apparently blank wall of steel and deftly manipulated an almost invisible dial set flush with its surface. "This is to keep the pa.s.sengers where they belong," he explained, as a section of the wall swung backward in a short arc and slid smoothly aside. "We will now proceed to see what makes it tick."

Ladder after ladder of steel they climbed, and bulkhead after bulkhead opened at Stevens's knowing touch. At each floor the mathematician explained to the girl the operation of the machinery there automatically at work--devices for heating and cooling, devices for circulating, maintaining, and purifying the air and the water--in short, all the complex mechanism necessary for the comfort and convenience of the human cargo of the liner.

Soon they entered the conical top compartment, a room scarcely fifteen feet in diameter, tapering sharply upward to a hollow point some twenty feet above them. The true shape of the room, however, was not immediately apparent, because of the enormous latticed beams and girders which braced the walls in every direction. The air glowed with the violet light of the twelve great ultra-light projectors, like searchlights with three-foot lenses, which lined the wall. The floor beneath their feet was not a level steel platform, but seemed to be composed of many lenticular sections of dull blue alloy.

"We are standing upon the upper lookout lenses, aren't we?" asked the girl. "Is that perfectly all right?"

"Sure. They're so hard that nothing can scratch them, and of course Roeser's Rays go right through our bodies, or any ordinary substance, like a bullet through a hole in a Swiss cheese. Even those lenses wouldn't deflect them if they weren't solid fields of force."

As he spoke, one of the ultra-lights flashed around in a short, quick arc, and the girl saw that instead of the fierce glare she had expected, it emitted only a soft violet light. Nevertheless she dodged involuntarily and Stevens touched her arm rea.s.suringly.

"All x, Miss Newton--they're as harmless as mice. They hardly ever have to swing past the vertical, and even if one shines right through you you can look it right in the eye as long as you want to--it can't hurt you a bit."

"No ultra-violet at all?"

"None whatever. Just a color--one of the many remaining crudities of our ultra-light vision. A lot of good men are studying this thing of direct vision, though, and it won't be long before we have a system that will really work."

"I think it's all perfectly wonderful!" she breathed. "Just think of traveling in comfort through empty s.p.a.ce, and of actually seeing through seamless steel walls, without even a sign of a window! How can such things be possible?"

"I'll have to go pretty well back," he warned, "and any adequate explanation is bound to be fairly deep wading in spots. How technical can you stand it?"

"I can go down with you middling deep--I took a lot of general science, and physics through advanced mechanics. Of course, I didn't get into any such highly specialized stuff as sub-electronics or Roeser's Rays, but if you start drowning me, I'll yell."

"That's fine--you can get the idea all x, with that to go on. Let's sit down here on this girder. Roeser didn't do it all, by any means, even though he got credit for it--he merely helped the Martians do it. The whole thing started, of course, when G.o.ddard shot his first rocket to the moon, and was intensified when Roeser so perfected his short waves that signals were exchanged with Mars--signals that neither side could make any sense out of. G.o.ddard's pupils and followers made bigger and better rockets, and finally got one that could land safely upon Mars.

Roeser, who was a mighty keen bird, was one of the first voyagers, and he didn't come back--he stayed there, living in a s.p.a.ce-suit for three or four years, and got a brand-new education. Martian science always was hot, you know, but they were impractical. They were desperately hard up for water and air, and while they had a lot of wonderful ideas and theories, they couldn't overcome the practical technical difficulties in the way of making their ideas work. Now putting other peoples' ideas to work was Roeser's long suit--don't think that I'm belittling Roeser at all, either, for he was a brave and far-sighted man, was no mean scientist, and was certainly one of the best organizers and synchronizers the world has ever known--and since Martian and Tellurian science complemented each other, so that one filled in the gaps of the other, it wasn't long until fleets of s.p.a.ce-freighters were bringing in air and water from Venus, which had more of both than she needed or wanted.

"Having done all he could for the Martians and having learned most of the stuff he wanted to know, Roeser came back to Tellus and organized Interplanetary, with scientists and engineers on all three planets, and set to work to improve the whole system, for the vessels they used then were dangerous--regular mankillers, in fact. At about this same time Roeser and the Interplanetary Corporation had a big part in the unification of the world into one nation, so that wars could no longer interfere with progress."

"With this introduction I can get down to fundamentals. Molecules are particles of the first order, and vibrations of the first order include sound, light, heat, electricity, radio, and so on. Second order, atoms--extremely short vibrations, such as hard X-rays. Third order, electrons and protons, with their accompanying Millikan, or cosmic, rays. Fourth order, sub-electrons and sub-protons. These, in the material aspect, are supposed to be the particles of the fourth order, and in the energy aspect they are known as Roeser's Rays. That is, these fourth-order rays and particles seem to partake of the nature of both energy and matter. Following me?"

"Right behind you," she a.s.sured him. She had been listening intently, her wide-s.p.a.ced brown eyes fastened upon his face.

"Since these Roeser's Rays, or particles or rays of the fourth order, seem to be both matter and energy, and since the rays can be converted into what is supposed to be the particles, they have been thought to be the things from which both electrons and protons were built. Therefore, everybody except Norman Brandon has supposed them the ultimate units of creation, so that it would be useless to try to go any further...."

"Why, we were taught that they _are_ the ultimate units!" she protested.

"I know you were--but we really don't know anything, except what we have learned empirically, even about our driving forces. What is called the fourth-order particle is absolutely unknown, since n.o.body has been able to detect it, to say nothing of determining its velocity or other properties. It has been a.s.sumed to have the velocity of light only because that hypothesis does not conflict with observational data. I'm going to give you the generally accepted idea, since we have nothing definite to offer in its place, but I warn you that that idea is very probably wrong. There's a lot of deep stuff down there hasn't been dug up yet. In fact, Brandon thinks that the product of conversion isn't what we think it is, at all--that the actual fundamental unit and the primary mechanism of the transformation lie somewhere below the fourth order, and possibly even below the level of the ether--but we haven't been able to find a point of attack yet that will let us get in anywhere. However, I'm getting 'way ahead of our subject. To get back to it, energy can be converted into something that acts like matter through Roeser's Rays, and that is the empirical fact underlying the drive of our s.p.a.ce-ships, as well as that of almost all other vehicles on all three planets. Power is generated by the great waterfalls of Tellus and Venus--water's mighty scarce on Mars, of course, so most of our plants there use fuel--and is transmitted on light beams, by means of powerful fields of force to the receptors, wherever they may be. The individual transmitting fields and receptors are really simply matched-frequency units, each matching the electrical characteristics of some particular and unique beam of force. This beam is composed of Roeser's Rays, in their energy aspect. It took a long time to work out this tight-beam transmission of power, but it was fairly simple after they got it."

He took out a voluminous notebook, at the sight of which Nadia smiled.

"A computer might forget to dress, but you'd never catch one without a full magazine pencil and a lot of blank paper," he grinned in reply and went on, writing as he talked.