and they would meet cremation. It
was a fearful hazard, either way, but it had to be taken.

They were almost down, now, and still not quite far enough to the
left. The heat of that yawning crater rose toward them.

"Faster--_faster_!" he cried, fairly dragging her along with him.

A last dash--a breathless instant--and they stood there on the ground,
not three feet from the edge of doom.

Swooning with the heat, Marjorie swayed against him, murmured an
incoherent prayer.

"Take heart!" he whispered, lifting her bodily and bearing her some
yards away. "We're down--safe!"

* * * * *

Their safety was but relative, however, Kendrick well knew. Until they
could put miles between them and this monstrous disc, they were not
really safe. No telling how soon their escape might be discovered. No
telling what terrible means Cor might take of curbing their flight.

So as soon as Marjorie had recovered sufficiently to proceed, they
headed off across the desert at a fast walk toward Ajo, where he hoped
to catch the afternoon train for Gila Bend. From there, they could
board the limited for Tucson and points east, when it came through
from Yuma that night.

They had tuned out on the escalator rays, but continued on still
invisible--for the disc hung above them in plain view and it would
have been suicide to let themselves be seen.

Even so, Kendrick soon began to have an uneasy feeling of being
followed. He looked around from time to time, but could see nothing.
Were some of those invisible little creatures on their trail?

He said nothing to Marjorie of his anxiety, but presently she too
began glancing backward uneasily, every few steps.

"They are near us!" she said at length, in a whisper. "I can sense
them."

It was more than sense, they soon discovered. Little paddings became
quite audible, and once or twice they saw the sand scuffed up, not
twenty feet away, as though by a foot passing over it.

* * * * *

Meanwhile they were climbing a rise of ground, broken by many small
hummocks and dotted with thorny shrubs. On the other side, at the foot
of a long down-slope, lay Ajo.

Once they reached the summit, Kendrick felt sure they could
outdistance their pursuers on the descent. Already, if his watch was
right, the train was preparing to pull out. It would be a breathless
dash, but he was confident they could make it.

So he reassured Marjorie as b