Pollux accepted it gingerly. "What about it?"

"I used to be a pretty fair mechanic myself. I got to wondering just what one could build from the 'hardware' you two want to ship. I figure I could build a fair-sized still. With the "food­stuffs" you want to take a man would be in a position to make anything from vodka to grain alcohol. But I don't suppose you two young innocents noticed that?"

Castor looked at the list. "Is that so?"

"Hmm - Tell me: did you plan to sell this stuff to the govern­ment import agency, or peddle it on the open market?"

"Well, Dad, you know you can't make much profit unless you deal on the open market."

"So I thought. You didn't expect me to notice what the stuff was good for - and you didn't expect the customs agents on Mars to notice, either." He looked them over. "Boys, I intend to try to keep you out of prison until you are of age. After that I'll try to come to see you. each visiting day." He chucked the list back at them. "Guess again. And bear in mind that we raise ship Thursday - and that I don't care whether we carry cargo or not."

Pollux said, "Oh, for pity's sake, Dad! Abraham Lincoln used to sell whiskey. They taught us that in history. And Win­ston Churchill used to drink it."

"And George Washington kept slaves," his father agreed. "None of which has anything to do with you two. So scram!"

They left his study and passed through the living room; Hazel was there. She cocked a brow at them. "Did you get away with it?"

"No."

She stuck out a hand, palm up. "Pay me. And next time don't bet that you can outsmart your Pop. He's my boy."

Cas and Pol settled on bicycles as their primary article of export. On both Mars and Luna prospecting by bicycle was much more efficient than prospecting on foot; on the Moon the old-style rock sleuth with nothing but his skis and Shank's ponies to enable him to scout the area where he had landed his jumpbug had almost disappeared; all the prospectors took bi­cycles along as a matter of course, just as they carried climbing ropes and spare oxygen. In the Moon's one-sixth gravity it was an easy matter to shift the bicycles to one's back and carry it over any obstacle to further progress.

Mars' surface gravity is more than twice that of Luna, but it is still only slightly more than one-third Earth normal, and Mars is a place of flat plains and very gentle slopes; a cyclist could maintain fifteen to twenty miles an hour. The solitary prospector, deprived of his traditional burro, found the bicycle an acceptable and reliable, if somewhat less congenial, substi­tute. A miner's bike would have looked odd in the streets of Stockholm; over-sized wheels, doughnut sand tires, towing yoke and trailer, battery trickle charger, two-way radio, saddle bags, and Geiger-counter mount made it not the vehicle for a spin in the perk - but on Mars or on the Moon it fitted its purpose the way a canoe fits a Canadian stream.

Both planets imported their bicycles from Earth - until re­cently. Lunar Steel Products Corporation had lately begun making steel tubing, wire, and extrusions from native ore; Sears & Montgomery had subsidised an assembly plant to manufacture miner's bikes on the Moon under the trade name 'Lunocycle' and Looney bikes, using less than twenty per cent. by weight of parts raised up from Earth, undersold imported bikes by half.

Castor and Pollux decided to buy up second-hand bicycles which were consequently flooding the market and ship them to Mars. In interplanetary trade cost is always a matter of where a thing is gravity-wise - not how far away. Earth is a lovely planet but all her products lie at the bottom of a very deep 'gravity well," deeper than that of Venus, enormously deeper than Luna's. Although Earth and Luna average exactly the same distance from Mars in miles, Luna is about five miles per second 'closer' to Mars in terms of fuel and shipping cost.

Roger Stone released just enough of their assets to cover the investment. They were still loading their collection of tired bikes late Wednesday afternoon, with Cas weighing them in, Meade recording for him, and Pol hoisting. Everything else had been loaded; trial weight with the crew aboard would be taken by the port weightmaster as soon as the bicycles were loaded Roger Stone supervised the stowing, he being personally responsible for the ship being balanced on take off.

Castor and he went down to help Pol unload the last flat. "Some of these seem hardly worth shipping," Mr. Stone remarked.

"Junk, if you ask me," added Meade.

"Nobody asked you," Pol told her.

"Keep a civil tongue in your head," Meade answered sweetly, "or go find yourself another secretary."

"Stow it, Junior," admonished Castor. "Remember she's work­ing free. Dad, I admit they aren't much to look at, but wait a bit. Pol and I will overhaul them and paint them in orbit. Plenty of time to do a good job - like new."

"Mind you don't try to pass them off as new. But it looks to me as if you had taken too big a bite. When we get these inside and clamped down, there won't be room enough in the hold to swing a cat, much less do repair work. If you were thinking of monopolising the living space, consider it vetoed."

"Why would anyone want to swing a cat?" asked Meade. "The cat wouldn't like it. Speaking of that, why don't we take a cat?"

"No cats," her father replied. "I travelled with a cat once and I was in executive charge of its sand box. No cats."

"Please, Cap'n Daddy! I saw the prettiest little kitten over at the Haileys' yesterday and -"

"No cats. And don't call me "Captain Daddy." One or the other, but the combination sounds silly."

"Yes, Captain Daddy."

"We weren't planning on using the living quarters." Castor answered. "Once we are in orbit we'll string 'em outside and set up shop in the hold. Plenty of room."

A goodly portion of Luna City came out to see them off. The current mayor, the Honorable Thomas Beasley, was there to say good-by to Roger Stone; the few surviving members of the Founding Fathers turned out to honor Hazel. A delegation from the Junior League and what appeared to be approximately half of the male members of the senior class of City Tech showed up to mourn Meade's departure. She wept and hugged them all, but kissed none of them; kissing while wearing a space suit is a futile, low-caloric business.

The twins were attended only by a dealer who wanted his payment and wanted it now and wanted it in full.

Earth hung in half phase over them and long shadows of the Obelisk Mountains stretched over most of the field. The base of the Rolling Stone was floodlighted; her slender bow thrust high above the circle of brightness. Beyond her, masking the far side of the field, the peaks of Rodger Young Range were still shining in the light of the setting Sun. Glorious Orion glittered near Earth; north and east of it, handle touching the horizon, was the homely beauty of the Big Dipper. The arching depth of sky and the mighty and timeless monuments of the Moon dwarfed the helmeted, squatty figures at the base of the spaceship.

A searchlight on the distant control tower pointed at them; blinked red three times. Hazel turned to her son. "Thirty minutes, Captain."

"Right." He whistled into his microphone. "Silence, everyone! Please keep operational silence until you are underground Thanks for coming, everybody. Good-by!"

"Bye, Rog!"

"Good trip, folks!"

"Aloha!"

"Hurry back"

Their friends started filing down a ramp mto one of the field tunnels; Mr. Stone turned to his family. "Thirty minutes. Man the ship!"

"Aye aye, sir."

Hazel started up the ladder with Pollux after her. She stopped suddenly, backed down and stepped on his fingers. "Out of my way, youngster!" She jumped down and ran toward the group disappearing down the ramp. "Hey, Tom! Beasley! Wait! Half a mo-"