Somewhere down there, six thousand miles below the clouds that boiled in Helmuth's face, was the Bridge. The Bridge was thirty miles high and eleven miles wide and fifty-four miles long but it was only a sliver, an intricate and fragile arrangement of ice crystals beneath the bulging big, racing tornadoes.

On Earth, even in the West, the Bridge would have been the mightiest engineering achievement of all history, could the Earth have borne its weight at all. But on Jupiter, the Bridge was as precarious and perishable as a snowflake.

"Bob?" Dillon's voice asked. "What is it? You seem more upset than usual. Is it serious?"

Helmuth looked up. His superior's worn, young face, lantern-jawed and crowned by black hair already beginning to gray t the temples, was alight both with love for the Bridge and with the consuming ardor of the responsibility he had to bear. As always, it touched Helmuth and reminded him that the implacable universe had, after all, provided one warm corner in which human beings might huddle together.

"Serious enough," he said, forming the words with difficulty against the frozen inarticulateness Jupiter had forced upon him. "But not fatal, as far as I could see. There's a lot of hydrogen vulcanism on the surface, especially at the northwest end, and it looks like there must have been a big blast under the cliffs. I saw what looked like the last of a series of firefalls."

Dillon's face relaxed while Helmuth was talking, slowly, line by engraved line. "Oh. It was just a flying chunk then."

"I'm almost sure that was what it was. The cross draughts are heavy now. The Spot and the STD are due to pass each other some time next month, aren't they? I haven't checked, but I can feel the difference in the storms."

"So the chunk got picked up and thrown through the end of the Bridge. A big piece?"

Helmuth shrugged. "That end is all twisted away to the left, and the deck is burst into matchwood. The scaffolding is all gone, too, of course. A pretty big piece, all right, Charity two miles through at a minimum."

Dillon sighed. He, too, went to the window, and looked out. Helmuth did not need to be a mind reader to know what he was looking at. Out there, across the stony waste of Jupiter V plus 112,600 miles of space, the South Tropical Disturbance was streaming toward the great Red Spot, and would soon overtake it. When the whirling funnel of the STD more than big enough to suck three Earths into deepfreeze, passed the planetary island of sodium tainted ice which was the Red Spot, the Spot would follow it for a few thousand miles, at the same time rising closer to the surface of the atmosphere.

Then the Spot would sink again, drifting back toward the incredible jet of stress fluid which kept it in being a jet fed by no one knew what forces at Jupiter's hot, rocky, 22,000mile core, compacted down there under 16,000 miles of eternal ice. During the entire passage, the storms all over Jupiter became especially violent; and the Bridge had been forced to locate in anything but the calmest spot on the planet, thanks to the uneven distribution of the few "permanent" landmasses.