ch. But come on,
never mind."

They crept to the mouth of the cavern and peered in. "Ugh," said
Maget.

He drew back with a shudder. The floor of the mine was covered with a
grey slush, in which were seething white masses of slugs weaving in
the slime. A powerful, rotten odor breathed in their faces, as though
they stood in the mouth of a great giant.

"Ah!" yelled Durkin, throwing his arms across his face.

The greenish, ghostly light which emanated from the slime was weaker
than moonlight, just enough to see by; a vast shadow hovered above
their heads, as though a gigantic bat flew there. The sweep and beat
of great wings drove them back, and they fled in terror from such
awful corruption.

But the flying monster, with a wing spread of eight feet, dashed past
them, and silhouetted against the rising moon like a goblin. Then came
another, and finally a flock of the big birds.

Durkin and Maget ran away, passing the stone house which stood near
the cavern's mouth. The booming sounds from the bowels of the earth
filled their ears now, and it was not thunder; no, it issued from the
depths of the mine.

"We--we got to get somethin' to eat," said Durkin, as they paused near
one of the shacks, in which shone a light.

* * * * *

Sounds of voices came from the interior. They crept closer, and
listened outside the window. Inside, they could see Espinosa, Gurlone
senior, and the big youth with the golden beard, Gurlone junior.

"Yes, father," the young man was saying. "I believe we had better
leave, at once. It's getting dangerous. I've reached the five million
mark now, with the new process, and it is ready to work with or sell,
just as we wish."

"Hear that?" whispered Durkin triumphantly. "Five million!"

"It's all ready, in the stone house," said young Gurlone.

"Why should we leave now?" said old Gurlone, his livid face working.
"Now, when we are just at the point of success in our great
experiments? So far, while we have struck many creatures of abnormal
growth, still, we have overcome them."

"Well, father, there is something in the mine now which makes it too
dangerous to work. That is, until they are put out of the way. You can
hear them now."

The three inside the shack listened, and so did Durkin and Maget. The
booming sounds swelled louder and the earth of the valley shook.

"I t'ink we better go," said Espinosa gruffly. "I agree with your son,
Professor."

"No,