It was a contrast that made each of them appreciate more fully the gift that a hot, blazing sun really is. Perhaps that was what made Fuller ask: "If this happened to a star so much like our sun, why couldn't it happen to Sol?"

"Perhaps it may," said Morey softly. "But the eternal optimism of man keeps us saying: 'It can't happen here.' And besides—" He put a hand on the wall of the ship, "—we don't ever have to worry about anything like that now. Not with ships like this to take us to a new sun—a new planet."

Arcot lifted the ship and flew over the cold, frozen ground beneath them, following the route indicated on the great globe in the dead city. Mile after mile of frozen ice fields flew by as they shot over it at three miles per second.

Suddenly, the bleak bulk of a huge mountain loomed gigantic before them. Arcot reversed the power and brought the ship to a stop. With the powerful searchlight, he swept the area, looking for the tower he knew should be here. At last, he made it out, a pyramid rather than a tower, and coated over with ice. They soon thawed out the frozen gasses by playing the energy of three powerful searchlights upon them, and in a few minutes the glint of gold showed through the melting ice and show.

"It looks," said Wade, "as though they have an outer wall of gold over a strong wall of iron or steel to protect it from corrosion. Certainly gold doesn't have enough tensile strength to hold itself up under this gravity—not in such masses as that."

Arcot brought the ship down beside the tower and the men once more went out through the airlock into the cold of the almost airless world. They flew across to the pyramid and looked for some means of entrance. In several places, they noticed hieroglyphics carved in great, foot-high characters. They searched in vain for a door until they noticed that the pyramid was not perfect, but truncated, leaving a flat area on top. The only joint in the walls seemed to be there, but there was no handle or visible methods of opening the door.

Arcot turned his powerful light on the surface and searched carefully for some opening device. He found a bas-relief engraving of a hand pointing to a corner of the door. He looked more closely and found a small jewel-like lens set in the metal.

Suddenly the men felt a vibration! There was a heavy click, and the door panel began to drop slowly.

"Get on it!" Arcot cried. "We can always break our way out if we're trapped!"

The four men leaped on it and sank slowly with it. The massive walls of the tower were nearly five feet thick, and made of some tough, white metal.