Hot Planet

bonus yet? — but your work isn’t done.”

“It wasn’t luck,” Zaino retorted. Burkett, in spite of her voice, seemed much less of a schoolmistress when encased in a space suit and carrying a shovel, so he was able to talk back to her. “I was simply alert enough to make use of existing conditions, which I had to observe for myself in spite of all the scientists around. I’m charging the achievement to my regular salary. I saw—”

He stopped suddenly, both with tongue and shovel. Then, “Captain!”

“What is it?”

“The only reason we’re starting this wall here is to keep well ahead of the flow so we can work as long as possible, isn’t it?”

“Yes, I suppose so. I never thought of trying anywhere else. The valley would mean a much shorter dam, but if the flow isn’t through it by now it would be before we could get there — oh! Wait a minute!”

“Yes; sir. You can put the main switch anywhere in a D. C. circuit. Where are the seismology stores we never had to use?”

Four minutes later the tractor set out from the Albireo, carrying Rawson and Zaino. Six minutes after that it stopped at the base of the ash cone which formed the north side of the valley from which the lava was coming. They parked a quarter of the way around the cone’s base from the emerging flood and started to climb on foot, both carrying burdens.

Forty-seven minutes later they returned empty-handed to the vehicle, to find that it had been engulfed by the spreading liquid.

With noticeable haste they floundered through the loose ash a few yards above the base until they had outdistanced the glowing menace, descended and started back across the plain to where they knew the ship to be, though she was invisible through the falling detritus. Once they had to detour around a crack. Once they encountered one, which widened toward the chasm on their right, and they knew a detour would be impossible. Leaping it seemed impossible, too, but they did it. Thirty seconds after this, forty minutes after finding the tractor destroyed, the landscape was bathed in a magnesium-white glare as the two one-and-a-half kiloton charges planted just inside the crater rim let go.

“Should we go back and see if it worked?” asked Zaino.

“What’s the use? The only other charges we had were in the tractor. Thank goodness they were nuclear instead of H. E. If it didn’t work we’d have more trouble to get back than we’re having now.”

“If it didn’t work, is there any point in going back?” “Stop quibbling and keep walking. Dr. Burkett, are you listening?”

“Yes, Captain.”

“We’re fresh out of tractors, but if you want to try it on foot you might start a set of flow measures on the lava. Arnie wants to know whether our landslide slid properly.”

However, the two were able to tell for themselves before getting back to the Albireo.

The flow didn’t stop all at once, of course; Nit with the valley feeding it blocked off by a pile of volcanic ash four hundred feet high on one side, nearly fifty on the other and more than a quarter of a mile long, its enthusiasm quickly subsided. It was thin, fluid stuff, as Burkett had noted; but as it spread it cooled, and as it cooled it thickened.

Six hours after the blast it had stopped with its nearest lobe almost a mile from the ship, less than two feet thick at the edge.

When Mardikian’s tractor arrived, Burkett was happily trying to analyze samples of the flow, and less happily speculating on how long it would be before the entire area would be blown off the planet. When Marini’s and Harmon’s vehicles arrived, almost together, the specimens had been loaded and everything stowed for acceleration. Sixty seconds after the last person was aboard, the Albireo left Mercury’s surface at two gravities.

The haste, it turned out, wasn’t really necessary. She had been in parking orbit nearly forty-five hours before the first of the giant volcanoes reached its climax, and the one beside their former site was not the first. It was the fourth.

“And that seems to be that,” said Camille Burkett rather tritely as they drifted a hundred miles above the little world’s surface. “Just a belt of white-hot calderas all around the planet. Pretty, if you like symmetry.”

“I like being able to see it from this distance,” replied Zaino, floating weightless beside her. “By the way, how much bonus should I ask for getting that idea of putting the seismic charges to use after all?”

“I wouldn’t mention it. Any one of us might have thought of that. We all knew about them.”

“Anyone might have. Let’s speculate on how long it would have been before anyone did.”

“It’s still not like the other idea, which involved your own specialty. I still don’t see what made you suppose that the gas pillar from the volcano would be heavily charged enough to reflect your radio beam. How did that idea strike you?”

Zaino thought back, and smiled a little as the picture of lightning blazing around pillar, cloud and mountain rose before his eyes.

“You’re not quite right,” he said. “I was worried about it for a while, but it didn’t actually strike me.”

It fell rather flat; Camille Burkett, Ph.D., had to have it explained to her.