Checkup excitement began within the farm dome as soon as the main fluorescents were turned on. There was a wild noise and a mad scurry. Sand-cars were brought out in rows, each farmboy tending his own.

Makiari was here and there, never too long at any one point. Hennes, in his flat, efficient voice, assigned the parties and set the routes across the farm's vast expanse. He looked up as he passed David and stopped.

"Williams," he said, "are you still of a mind to be on the checkup?"

"I wouldn't miss it."

"All right then. Since you haven't any car of your own, I'll assign you one out of general stock. Once it's assigned, it's yours to take care of and keep in working condition. Any repairs or damage which we consider avoidable will come out of your pay. Understood?"

"Fair enough."

"I'll put you on Griswold's team. I know that you and he don't get along, but he's our best man in the fields and you're an Earthie without experience. I wouldn't care to load you onto a lesser man. Can you drive a sand-car?"

"I think I can handle any moving vehicle with a little practice."

"You can, eh? We'll give you your chance to make good on that." He was about to step away when his eyes caught something. He barked, "And where do you think you're going?"

Bigman had just stepped into the assembly room. He was in a new outfit and his boots had been polished to mirror-shine. His hair was slicked down and his face was scrubbed and pink. He drawled, "On the checkup, Hennes-Mister Hennes. I'm not on detention and I still have my rating as licensed farmboy even though you have put me on chow detail. That means I can go on checkup. It also means I have a right to my old car and my old squad."

Hennes shrugged. "You read the rule books a lot, and that's what they say, I suppose. But one more week, Bigman, one more week. After that, if you ever show your nose anywhere on Makian territory I'll have a real man step on you and squash you."

Bigman made a threatening gesture at Hennes's retreating back and then turned to David. "Ever used a nosepiece, Earthman?"

"Never actually. I've heard about them, of course."

"Hearing isn't using. I've checked an extra one out for you. Look, let me show you how to get it on. No, no, get your thumbs out of there. Now watch how I hold my hands. That's right. Now over the head and make sure the straps aren't twisted in the back of the neck, or you'll end with a headache. Now can you see through them?"

The upper part of David's face was transformed into a plastic-encased monstrosity, and the double hose leading from the oxygen cylinders up each side of his chin subtracted further from any appearance of humanity.

"Do you have trouble breathing?" asked Bigman.

David was struggling, fighting to suck in air. He yanked the nosepiece off. "How do you turn it on? There's no gauge."

Bigman was laughing. "That's the return for the scare you gave me last night. You don't need a gauge. The cylinders automatically feed oxygen as soon as the warmth and pressure of your face trip a contact; and it automatically closes off when you take it off."

"Then there's something wrong with it. I- "

"Nothing wrong with it. It feeds at a gas pressure of one fifth normal to match the pressure of the Mars atmosphere, and you can't suck it in out here when you're fighting the pressure of a normal Earth atmosphere. Out there in the desert it will be fine. And it will be enough, too, because even though it's one fifth normal, it's all oxygen. You'll have as much oxygen as you always had. Just remember one thing: breathe in through your nose but breathe out through your mouth. If you breathe out through your nose, you'll fog up your eyepieces, and that won't be good."

He strutted about David's tall, straight body and shook his head. "Don't know what to do about your boots. Black and white! You look like a garbage detail or something." He glanced down at his own chartreuse-and-vermilion creations with more than a little complacency.

David said, "I'll manage. You'd better get to your car. It looks as though they're getting ready to move."

"You're right. Well, take it easy. Watch out for the gravity change. That's hard to take if you're not used to it. And, Earthman____________________ "

"Well."

"Keep your eyes open. You know what I mean."

"Thanks. I shall."

The sand-cars were lining up now in squares of nine. There were more than a hundred all told, each with its farmboy peering over its tires and controls. Each vehicle had its handmade signs intended as humor. The sand-car trundled out for David was speckled with such signs from half-a-dozen previous owners, beginning with a "Watch Out, Girls" circling the bullet-like prow of the car and ending with a "This Ain't No Dust Storm, This Is Me," on the rear bumper.

David climbed in and closed the door. It fit tightly. Not even a seam showed. Immediately above his head there was the filtered and refiltered vent that allowed equalization of air pressure within and without the car. The glass was not quite clear. It had a faint misting that was proof of dozens of dust storms met and weathered. David found the controls familiar enough. They were standard for ground cars, for the most part. The few unfamiliar buttons explained themselves upon manipulation.

Griswold came past, gesturing at him furiously. He opened his door.

Griswold yelled, "Get your front flaps down, you jerk. We're not heading into any storm."

David searched for the proper button and found it on the steering-wheel shaft. The windshields, which looked as though they were welded to metal, disengaged themselves and sank down into sockets. Visibility improved. Of course, he thought. Mars's atmosphere would scarcely, raise wind enough to disturb them, and this was Martian summer. It would not be too cold.

A voice called, "Hey, Earthman!" He looked up. Bigman was waving at him. He was in Griswold's group of nine also. David waved back.

A section of the dome lifted up. Nine cars trundled in, moving sluggishly. The section closed behind them. Minutes passed, then it opened, empty, and nine more moved in.

Griswold's voice sounded suddenly and loudly next to David's ear. David turned and saw the small receiver in the car top just behind his head. The small grilled opening at the head of the steering-wheel shaft was a mouthpiece.

"Squad eight, ready?"

The voices sounded consecutively: "Number one, ready." "Number two, ready." "Number three, ready." There was a pause after number six. Just a few seconds. David then called, "Number seven, ready." There followed "Number eight, ready." Big-man's reedy tones came last. "Number nine, ready."

The dome section was raising again and the cars ahead of David began moving. David slowly stepped on the resistor, cutting the coils, allowing electricity to pour into the motor. His sand-car leaped ahead, all but crashing into the rear of the one in front. He let out the resistor with a jerk and felt the car tremble beneath him. Gently he babied it along. The section enclosed them like a small tunnel, shutting off behind.

He became conscious of the hiss of air being pumped out of the section back into the dome proper. He felt his heart begin to pound, but his hands were steady upon the wheel.

His clothing bellied away from him and the air was seeping out along the cylindrical line where boots met thigh. There was a tingling in his hands and chin, a feeling of puffiness, of distention. He swallowed repeatedly, to relieve the gathering pain in his ears. After five minutes he found himself panting in an effort to gather enough oxygen for his needs.

The others were slipping on their nosepieces. He did the same, and this time oxygen slid smoothly up Ms nostrils. He breathed deeply, puffing it out through his mouth. His arms and feet still tingled, but the feeling was beginning to die away.