The larger of the specks that had appeared on the horizon resolved itself into a handling-machine, a thing like an oversized contragravity-tank, with a bulldozer-blade, a stubby derrick-boom instead of a gun, and jointed, claw-tipped arms to the sides. The smaller dots grew into personal armor—egg-shaped things that sprouted arms and grab-hooks and pushers in all directions. The man with the grizzled beard began talking rapidly into his hand-phone, then hung it up. There was a series of bumps, and the armor-tender, weightless on contragravity, shook as the handling-machine came aboard.

"You ever see any nuclear bombing, Miss Quinton?" the young man with the hairy legs asked, offering her his candy bag.

"Only by telecast, back Sol-side," she replied, helping herself. "Test-shots at the Federation Navy proving-ground on Mars. I never even heard of nuclear bombs being used for mining till I came here, though."

"Well, if this turns out as well as the other job, three months ago, it'll be something to see," he promised. "These volcanoes have been dormant for, oh, maybe as long as a thousand years; there ought to be a pretty good head of gas down there. And the magma'll be thick, viscous stuff, like basalt on Terra. Of course, this won't be anything like basalt in composition—it'll be intensely compressed metallic fluorides, with a very high metal-content. The volcanoes we shot three months ago yielded a fine flow of lava with all sorts of metals—nickel, beryllium, vanadium, chromium, indium, as well as copper and iron."

"What sort of gas were you speaking about?" she asked.

"Hydrogen. That's what's going to make the fireworks; it combines explosively with fluorine. The hydrogen-fluorine combination is what passes for combustion here; the result is hydrofluoric acid, the local equivalent of water. See, the metallic core of this planet is covered, much less thickly than that of Terra, with fluoride rock—fluorspar, and that sort of thing. There's nothing like granite here, for instance. That's why those big dunes, out there, are the best Niflheim has in the way of mountains. The subsurface hydrogen is produced when the acid filters down through the rock, combines with pure metals underneath."

"Dr. Murillo's inside, now," the radioman said. "Just came out of the inner airlock. He'll be up as soon as he gets out of his pressure-suit."

"As soon as he gets here, I'll touch it off," the bearded man said. "Everything set, de Jong?"

"Everything ready, Dr. Gomes," one of his assistants assured him.

The door at the rear of the control-cabin opened, and Juan Murillo, the seismologist, entered, followed by an assistant. Murillo was a big man, copper-skinned, barrel-chested; he looked like a third-or fourth-generation Martian, of Andes Indian ancestry. He came forward and stood behind Gomes' chair, looking down at the instruments. His assistant stopped at the door. This assistant was not human. He was a biped, vaguely humanoid, but he had four arms and a face like a lizard's, and, except for some equipment on a belt, he was entirely naked.