way into the water,
following the course of the stream, and having the others trail along in
single file directly behind him.

When they halted again Bushnell assured them that there was little
danger that the bandits would be able to follow them closely, and they
rested without molestation till morning.

At daybreak the Westerner was astir, being alive with eagerness and
impatience, as he repeatedly declared they would behold the wonderful
Silver Palace before another sunset.

Eating a hasty breakfast, they pushed forward, with the Westerner in the
lead.

Once more the tower of smoke, which they had noted the day before, was
before them, but now it seemed blacker and more ominous than on the
previous day.

It was not far from midday when, away to the westward, they heard
rumbling sounds, like distant thunder.

"Vot id vas, ain'd id?" asked Hans, in alarm. "I don'd seen no dunder
shower coming up somevere, do I?"

"It did not seem like thunder," said Frank, soberly. "It was more like a
rumbling beneath the ground, and I fancied the earth quivered a bit."

"Perhaps it is an earthquake," put in the professor, apprehensively. "I
believe they have such convulsions of nature in this part of the world."

Bushnell said nothing, but there was a troubled look on his face, and he
urged them all forward at a still swifter pace.

The smoke tower was now looming near at hand, and they could see it
shift and sway, grow thin, and roll up in a dense, black mass. It cast a
gloom over their spirits, and made them all feel as if some frightful
disaster was impending.

Again and again, at irregular intervals, they heard the sullen rumbling,
and once all were positive the earth shook.

It was noticed that directly after each rumbling the smoke rolled up in
a thick, black mass that shut out the light of the sun and overcast the
heavens.

The professor was for turning back, but Bushnell was determined to go
forward, and Frank was equally resolute. Hans had very little to say,
but his nerves were badly shaken.

"In less than an hour we shall be able to see the Silver Palace,"
assured Bushnell. "We would be fools to turn back now."

So they went on, and, at last, they climbed to the top of a rise, from
which point the Westerner assured them that the palace could be seen.

An awe-inspiring spectacle met their gaze. They looked across a great
gulf, from which the smoke was rolling upward in clouds, and out of
which came the s