If he had kept his eyes open, he would have seen how big a charge it was and known how far to give back. Dad said, "Oh, say amile and a half—or even two miles. And keep backing."

Saunders looked at him, snorted disgustedly, and stalked away. We backed out of range and let her blow.

While we were setting the next charge I could see George's lips moving. After a while he said, "Figuring gumbo mud conservatively at a hundred pounds per cubic foot it would take one full load of the Mayflower to give Mr. Saunders alone the kind of a farm he would like to have handed to him. At that rate it would take just an even thousand G-years—five hundred Earth years—for the Mayflower to truck in top-soil for farms for our entire party."

"You forgot the Covered Wagon," I said brightly.

George grinned. "Oh, yes! When the Covered Wagon iscommissioned and in service we could cut it down to two hundred and fifty years—provided no new immigrants came in and there was a ban on having babies!" He frowned and added, "Bill, why is it that some apparently-grown men never learn to do simple arithmetic?" I didn't know the answer, so he said, "Come on, Bill, let's get on with our blasting. I'm afraid we'll just have to piddle along in our inefficient way, even if it doesn't suit our friend Saunders."

The morning the crusher was scheduled to show up I was waiting for it at the end of the road. It came breezing down the road at twenty miles an hour, filling it from side to side. When it came to the wall of lava, it stopped. I waved to the operator; he waved back, then the machine grunted a couple of times, inched forward, and took a bite out of the lava.

Lava didn't bother it; it treated it like peanut brittle. A vibro-cutter built into its under carriage would slice under the flow like a housewife separating biscuit from a pan, the big steel spade on the front of the thing would pry under and crack the bite off, and the conveyor would carry the chunk up into the jaws.

The driver had a choice of dropping the chewed up material under the rear rollers or throwing it off to the side. Just now he was throwing it away, leaving the clean slice made by the vibro-cutter as a road bed —a good road, a little dusty but a few rains would fix that.

It was terrifically noisy but the driver didn't seem to mind. He seemed to enjoy it; there was a good breeze taking the dust away from him and he had his anti-silicosis mask pushed up on his forehead, showing the grin on his face.

By noon he was down to our place and had turned in. We had a bite to eat together, then he started in levelling a farm for me—five acres, the rest would have to wait. At that I was lucky for I was to get land to work months ahead of the original schedule. The second trip of the Mayflower had brought in three more crushers and very few immigrants, just enough to replace those who had given up and gone back out of our party, that being the compromise the town council had worked out with the Colonial Commission.

The racket was still worse when the crusher bit into hard rock, instead of lava, but it was music to me and I didn't get tired of watching. Every bite was a piece of land to me. At suppertime the second-shift driver showed up with Dad. We watched together for a while, then Dad went back to town. I stayed. About midnight I went over into a stretch that was not to be processed now, found a big rock to keep the Sun out of my eyes and laydown for a quick nap.

Then the relief driver was shaking me and saying, "Wake up, kid—you got a farm."

I stood up and rubbed my eyes and looked around. Five acres, with just enough contour for drainage and a low hummock in the middle where the house would sit. I had a farm.

The next logical thing to do would have been to get the house up, but, under the schedule, I rated the use of a cud-chewer for the following week. A cud-chewer is a baby rock crusher. It uses a power pack instead of an antenna, it is almost fool proof and anybody can run one, and it finishes up what the crusher starts. It is small and low-powered compared with a crusher. The colony had about forty of them.

The crusher left loose rubble several feet deep in pieces as big as my fist. The cud-chewer had a fork spade on the front of it, several sizes of spade forks, in fact. The coarse fork went down into the loose rocks about eighteen inches and picked up the big ones. These drifted back into the hopper as the machine moved forward and were busted into stuff about the size of walnuts.

When you had been over the ground once with the coarse fork, you unshipped it and put on the medium fork and reset the chewing rollers. This time you went down only ten inches and the result was gravel. Then you did it again for medium-fine and then fine and when you were done the upper six inches or so was rock flour, fine as the best loam—still dead, but ready to be bred into life.

Round and round and round, moving forward an inch at a time. To get real use out of your time allotment the cud-chewer had to be moving twenty-four hours a day until they took it away from you. I stayed at it all through the first day, eating my lunch in the saddle. Dad spelled me after supper and Hank came out from town and we alternated through the night-light phase it was, actually, it being Monday night.

Papa Schultz found me asleep with my head on the controls late next afternoon and sent me back to his house to get some real sleep. Thereafter one of the Schultzes always showed up when I had been at it alone for four or five hours. Without the Schultzes I don't know how Dad and I would have gotten through the dark phase of that week.

But they did help and by the time I had to pass the cud-chewer along I had nearly three and a half acres ready to be seeded with pay dirt.

Winter was coming on and I had my heart set on getting my house up and living in it during the winter month, but to do so I really had to hump. I had to get some sort of a holding crop in or the spring thaw would wash my top soil away. The short Ganymede year is a good idea and I'm glad they run it that way; Earth's winters are longer than necessary. But it keeps you on the jump.

Papa Schultz advised grass; the mutated grass would grow in sterile soil much like growing things in hydroponic solutions. The mat of rootlets would hold my soil even if the winter killed it and the roots would furnish something through which the infection could spread from the "pay dirt."

Pay dirt is fundamentally just good black soil from Earth, crawling with bacteria and fungi and microscopic worms—everything you need but the big fishing worms; you have to add those. However, it wouldn't do simply to ship Earth dirt to Ganymede by the car load. In any shovelful of loam there are hundreds of things, plant and animal, you need for growing soil—but there are hundreds of other things you don't want. Tetanus germs. Plant disease viruses. Cut worms. Spores. Weed seeds. Most of them are too small to be seen with the naked eye and some of them can't even be filtered out

So to make pay dirt the laboratory people back on Earth would make pure cultures of everything they wanted to keep in the way of bacteria, raise the little worms under laboratory conditions, do the same for fungi and everything else they wanted to save—and take the soil itself and kill it deader than Luna, irradiate it, bake it, test it for utter sterility. Then they would take what they had saved in the way of life forms and put it back into the dead soil That was "pay dirt," the original pay dirt. Once on Ganymede the original stuff would be cut six ways, encouraged to grow, then cut again. A hundred weight of pay dirt supplied to a ‘steader might contain a pound of Terra's own soil.

Every possible effort was made to "limit the invasion," as the ecologists say, to what was wanted. One thing that I may not have mentioned about the trip out was the fact that our clothes and our baggage were sterilized during the trip and that we ourselves were required to take a special scrub before we put our clothes back on. It was the only good bath I got the whole two months, but it left me smelling like a hospital.