of a rainbow.

"Look at those Indians watching us," remarked Ned to Tom, as he
paused in his chipping of the frozen surface. The young inventor
glanced up toward the distant plateau where a fringe of dark figures
stood. The natives were evidently intently watching the gold-seekers.

"Do you think there's any danger from them. Abe?" asked Tom.

"Not much," was the reply. "They made trouble for me an' my partner,
but I guess th' airship has scared 'em sufficient, so they won't
come snoopin' down here," and Abe fell to at his digging again.

Mr. Damon was also vigorously wielding a pick, but Mr. Parker like
the true scientist he was, had renewed his observations. Evidently
the gold had no attractions for him, or, if it did, he preferred to
wait until he had finished his calculations.

Vigorously the adventurers wielded their implements, making the ice
fly, but for an hour or more no gold was discovered. Mr. Damon,
after picking lightly at a certain place, would get discouraged, and
move on to another. So did Ned, and Tom, after going down quite a
way, left off work, and walked over to one of the big ice caves.

"What's up?" asked Ned, resting from his labors.

"I was thinking whether it would be safe to put the RED CLOUD in
this ice cave for a shelter," replied Tom. "There may come up a hail
storm at any time, and damage it. The caves would be just the place
for it, only I'm afraid the roof might collapse."

"It looks strong," said Ned. "Let's ask Mr. Parker his opinion."

"Good idea," agreed Tom.

The scientist was soon taking measurements of the thickness of the
cave roof, noting its formation, and looking at the frozen floor.

"I see no reason why this cave should collapse," he finally
announced. "The only danger is the movement of the whole valley of
ice, and that is too gradual to cause any immediate harm. Yes, I
think the airship could be housed in the ice cave."

"Then I'll run her in, and she'll be safer," decided Tom. "I guess
we three can do it, Ned, and leave Mr. Damon and Abe to keep on
digging for gold." The airship was so buoyant that it could easily
be moved about on the bicycle wheels on which it rested, and soon,
after the lower edge of the opening into the ice cave had been
smoothed down, the RED CLOUD was placed in the novel shelter.

"Now to continue the search for the yellow nuggets!" cried Ned, and
Tom went with him, even Mr. Parker condescending to take a pick,
now. Abe was the only on