to do his best to get on our trail. Of course he can't follow
us through the air, but he'll note in what direction we start and as
soon as we are out of sight he and his men will hit the trail in the
same direction."

"What, and leave the camp?" asked Ned.

"Yes, though they'll probably skip off with some of our supplies.
That's why I'm going to take along an unusually large supply. We may
not come back to this camp at all. In fact, it won't be much use
after Delazes and his crowd clean it out and leave."

"And you really think they'll do that, Tom?" asked his chum.

"I'm almost sure of it, from the way the Mexicans have been acting
lately. Delazes has been hinting around trying to surprise me into
saying which direction we're going to take. But I've been careful.
The sight of that golden image aroused him and his men. They're
hungry for gold, and they'd do away with us in a minute if they
thought they could find what we're looking for and get it without
us. But our secret is ours yet, I'm glad to say. If only the balloon
behaves we ought soon to be in the--"

"Hark!" exclaimed Ned, holding up a warning hand. They heard a
rustling outside the tent, and one side bulged in, as if some one
was leaning against it.

"Some one's listening," whispered Ned.

Tom nodded. The next moment he drew his heavy automatic revolver and
remarked in loud tones:

"My gun needs cleaning. I'm going to empty it through the tent where
that bulge is--look out, Ned."

The bulge against the canvas disappeared as if by magic, and the
sound of some one crawling or creeping away could be heard outside.
Tom laughed.

"You see how it is," he said. "We can't even think aloud."

"Bless my collar button; who was it?" asked Mr. Damon.

"Some of Delazes's men--or himself," replied the young inventor.
"But I guess I scared him."

"Maybe it was Andy Foger," suggested Ned with a smile.

"No, I guess we've lost track of him and his father," spoke Tom.
"I've kept watch of the back trail as much as I could, and haven't
seen them following us. Of course they may pick up our trail later
and come here, and they may join forces with the Mexicans. But I
don't know that they can bother us, once we're off in the balloon."

To Tom's disappointment, the next day proved stormy, a heavy rain
falling, so it was impossible to test the balloon with the gas. The
camp was a disconsolate and dreary place, and even Eradicate,
usually so jolly, was cross and ou