At that time Grimes had not yet succumbed to the new style in architecture. The London Plan did not appeal to him; he liked a house aboveground, where he could see it. When it became necessary to increase the floor space in his offices, he finally gave in and went subsurface, not so much for the cheapness, convenience, and general all-around practicability of living in a tri-conditioned cave, but because he had already become a little worried about the possible consequences of radiation pouring through the human body. The fused-earth walls of his new residence were covered with lead; the roof of the cave had a double thickness. His hole in the ground was as near radiation- proof as he could make it. ‘-the meat of the matter,' Stevens was saying, ‘is that the delivery of power to transportation units has become erratic as the devil. Not enough yet to tie up traffic, but enough to be very disconcerting. There have been some nasty accidents; we can't keep hushing them up forever. I've got to do something about it.

‘Why?

"Why?" Don't be silly. In the first place as traffic engineer for NAPA my bread and butter depends on it. In the second place the problem is upsetting in itself. A properly designed piece of mechanism ought to work - all the time, every time. These don't, and we can't find out why not. Our staff mathe­matical physicists have about reached the babbling stage.

Grimes shrugged. Stevens felt annoyed by the gesture. ‘I don't think you appreciate the importance of this problem, Doc. Have you any idea of the amount of horsepower involved in transportation? Counting both private and commercial vehicles and common carriers, North American Power-Air supplies more than half the energy used in this continent. We have to be right. You can add to that our city-power affiliate. No trouble there, yet. But we don't dare think what a city-power breakdown would mean.

‘I'll give you a solution.

‘Yeah? Well, give.

‘Junk it. Go back to oil-powered and steam-powered vehicles. Get rid of these damned radiant-powered deathtraps.

‘Utterly impossible. You don't know what you're saying. It took more than fifteen years to make the change-over. Now we're geared to it. Gus, if NAPA closed up shop, half the population of the northwest seaboard would starve, to say nothing of the lake states and the Philly-Boston axis.

‘Hrrmph- Well, all I've got to say is that that might be better than the slow poisoning that is going on now.

Stevens brushed it away impatiently. ‘Look, Doc, nurse a bee in your bonnet if you like, but don't ask me to figure it into my calculations. Nobody else sees any danger in radiant power.

Grimes answered mildly. ‘Point is, son, they aren't looking in the right place. Do you know what the high-jump record was last year?

‘I never listen to the sports news.

‘Might try it sometime. The record levelled off at seven foot two, ‘bout twenty years back. Been dropping ever since. You might try graphing athletic records against radiation in the air - artificial radiation. Might find some results that would surprise you.

‘Shucks, everybody knows there has been a swing away from heavy sports. The sweat-and-muscles fad died out, that's all. We've simply advanced into a more intellectual culture.

‘Intellectual, hogwash! People quit playing tennis and such because they are tired all the time. Look at you. You're a mess.

‘Don't needle me, Doc.

‘Sorry. But there has been a clear deterioration in the per­formance of the human animal. If we had decent records on such things I could prove it, but any physician who's worth his salt can see it, if he's got eyes in him and isn't wedded to a lot of fancy instruments. I can't prove what causes it, not yet, but I've a damned good hunch that it's caused by the stuff you peddle.

‘Impossible. There isn't a radiation put on the air that hasn't been tested very carefully in the bio labs. We're neither fools nor knaves

‘Maybe you don't test ‘em long enough. I'm not talking about a few hours, or a few weeks; I'm talking about the cumu­lative effects of years of radiant frequencies pouring through the tissues. What does that do?

‘Why, nothing-I believe.

‘You believe, but you don't know. Nobody has ever tried to find out. F'rinstance - what effect does sunlight have on sili­cate glass? Ordinarily you would say "none", but you've seen desert glass?

‘That bluish-lavender stuff? Of course.

‘Yes. A bottle turns coloured in a few months in the Mojave Desert. But have you ever seen the windowpanes in the old houses on Beacon Hill?

‘I've never been on Beacon Hill.

‘OK, then I'll tell you. Same phenomena, only it takes a century more, in Boston. Now tell me, you savvy physics - could you measure the change taking place in those Beacon Hill windows?

‘Mm-rn-in - probably not.

‘But it's going on just the same. Has anyone ever tried to measure the changes produced in human tissue by thirty years of exposure to ultra short -wave radiation?

‘No, but-

‘No "buts". I see an effect. I've made a wild guess at a cause. Maybe I'm wrong. But I've felt a lot more spry since I've taken to invariably wearing my lead overcoat whenever I go out.

Stevens surrendered the argument. ‘Maybe you're right, Doc. I won't fuss with you. How about Waldo? Will you take me to him and help me handle him?

‘When do you want to go?

‘The sooner the better.

‘Now?

‘Suits.

‘Call your office.

‘Are you ready to leave right now? It would suit me. As far as the front office is concerned, I'm on vacation; nevertheless, I've got this on my mind. I want to get at it.

‘Quit talking and git.

They went topside to where their cars were parked. Grimes headed towards his, a big-bodied, old-fashioned Boeing family landau. Stevens checked him. ‘You aren't planning to go in that? It ‘u'd take us the rest of the day.

"Why not? She's got an auxiliary space drive, and she's tight. You could fly from here to the Moon and back.

‘Yes, but she's so infernal slow. We'll use my "broomstick"

Grimes let his eyes run over his friend's fusiformed little speedster. Its body was as nearly invisible as the plastic indus­try could achieve. A surface layer, two molecules thick, gave it a refractive index sensibly identical with that of air. When perfectly clean it was very difficult to see. At the moment it had picked up enough casual dust and water vapour to be faintly seen - a ghost of a soap bubble of a ship

Running down the middle, clearly visible through the walls, was the only metal part of the ship - the shaft, or, more pro­perly, the axis core, and the spreading sheaf of deKalb recep­tors at its terminus. The appearance was enough like a giant witch's broom to justify the nickname. Since the saddles, of transparent plastic, were mounted tandem oven the shaft so that the metal rod passed between the legs of the pilot and passengers, the nickname was doubly apt

‘Son,' Grimes remarked, ‘I know I ain't pretty, nor am I graceful. Nevertheless, I retain a certain residuum of self- respect and some shreds of dignity. I am not going to tuck that thing between my shanks and go scooting through the air on it

‘Oh, rats! You're old-fashioned.

‘I may be. Nevertheless, any peculiarities I have managed to retain to my present age I plan to hang on to. No.

‘Look - I'll polarize the hull before we raise. How about it?

‘Opaque?

‘Opaque.

Grimes slid a regretful glance at his own frumpish boat, but assented by fumbling for the barely visible port of the speed­ster. Stevens assisted him; they climbed in and straddled the stick

‘Atta boy, Doc,' Stevens commended, ‘I'll have you there in three shakes. That tub of yours probably won't do over five hundred, and Wheelchair must be all of twenty-five thousand miles up.