affair--"It's no use," panted the geologist, wishing that he could get a
handkerchief to his forehead. "We can't loosen it without tools."

Jackson was for trying again, but the doctor agreed with Van Emmon. They
reflected that they had been away from Smith long enough, anyhow. The
cube was out of sight from where they were.

Van Emmon turned the light on the walls of the anteroom, and found, on a
shelf at one end, a neat pile of those little reels, eleven in all. He
pocketed the lot. There was nothing else.

Jackson and Kinney started to go. They retreated as far into the main
room as their telephone wires would allow. Still the geologist held
back.

"Come on," said the doctor uneasily. "It's getting cold."

Next second they stopped short, nerves on edge, at a strange exclamation
from Van Emmon. They looked around to see him pointing his light
directly at the floor. Even in that unnatural suit of mail, his attitude
was one of horror.

"Look here," he said in a low, strained voice. They went to his side,
and instinctively glanced behind them before looking at what lay in the
dust.

It was the imprint of an enormous human foot.


The first thing that greeted the ears of the explorers upon taking off