ullen mutterings they had heard.

"Merciful goodness!" cried Professor Scotch. "It must be the crater of a
volcano!"

"Yah!" gasped Hans; "und der volcano vos doin' pusiness at der oldt
standt alretty yet."

"The volcano may have been dormant for centuries," said the professor,
"but it is coming to life now!"

"Where is the Silver Palace?" demanded Frank.

Bushnell clutched the boy's arm with a grip of iron, pointing straight
through the smoke clouds that rose before them.

"Look!" he shouted, hoarsely; "it is thar! See--the smoke grows thinner,
an' thar she am! See her glitter! In thet thar palace is stored enough
treasure ter make us richer then ther richest men in ther world, an' ten
thousand volcanoes ain't goin' ter keep me from it, you bet yer boots!"

True enough, through the parted smoke clouds gleamed the towers and
turrets of the wonderful palace that had remained hidden in the heart of
the mountains hundreds of years, jealously guarded by the fierce
natives, who believed it sacred, and who had kept the secret well from
the outside world.

CHAPTER XII.

DOOM OF THE SILVER PALACE.

Bushnell leaped from his horse and began tearing the packs from the
backs of the led animals. He worked with mad haste, and there was an
awesome, insane glare in his eyes.

"The man is crazy!" roared Professor Scotch. "The volcano is certain to
break forth before long--it must be on the verge of breaking forth now.
If we remain here we are doomed!"

"Oxcuse me!" fluttered Hans. "I vos retty to gone righd avay queek."

The professor turned to Frank with his appeal:

"Come, boy, let's get away before destruction comes upon us. We must not
remain here."

Frank sprang down from his snorting horse, flung the rein to Hans, and
leaped to Bushnell's side.

"You are mad to think of remaining here!" he said, swiftly. "Come away,
and we will return when the volcano is at peace."

"No!" thundered the treasure-seeker, "I will not go! The Silver Palace
is there, and I mean to have my share of the treasure. Go if you are
afraid, but here I stay till the balloon is inflated, and I can cross
the chasm. The wind is right for it, and nothing shall stop me!"

He picketed the horses, and began ripping open the packs.

Frank turned to Professor Scotch, saying, quietly:

"Bushnell will not go, and I shall stay with him. At the same time, I
advise you to go. Take Hans with you, and get away from here. Leave a
plain trail, a