It is needless to say that the three adventurers lost no time in climbing up the gang ladder.

They were not a moment too soon.

Frank had just cleared the rail when men burst from a thicket and sent a hail storm of bullets upward. They rattled on the steel hull of the air-ship.

“Give it to ’em!” shouted Nicodemus, angrily. “They deserve it richly.”

Barney and Pomp grabbed rifles and rushed to the rail.

But Frank cried:

“Wait! Do not take life unnecessarily! We are safe just now. Let us have a talk with them.”

Taking care not to expose himself, Frank shouted over the rail:

“Ahoy down there!”

The firing had ceased, and a voice—that of Dooley—came up in reply:

“Well, what do you want?”

“What do you mean by this unprovoked attack upon us?”

“You are our enemies!”

“How do you prove that?”

“Have you not come here to cheat us out of the gold buried under the lake, and which justly belongs to us?”

“Neither of us are able to secure it just now.”

“Well, but we shall be when the lake recedes.”

“In that event, why have we not as much right to a share of it as you?”

“That is neither here nor there. We lay claim to the gold, and don’t propose to divide with anybody.”

“What a pig-headed fellow,” said Frank, angrily. “I’ve a mind to teach him a lesson!”

“I wish you would,” said Nicodemus, eagerly.

“Look here, my friend,” shouted Frank, “let’s have no nonsense about this. That gold does not belong to you more than it does to us. For that matter, if I should choose, I could prevent your securing one jot of it. It is better for you to talk reason at once!”

“The only reason I will talk with you,” said Dooley, obstinately, “is that you go on about your business and leave us and our affairs alone!”

Frank turned from the rail.

“There is no use to talk with that fellow,” he said.

“What shall we do?” asked Nicodemus.

“I will think up a plan,” said the young inventor, “in the meanwhile our best plan is to sail over to the other side of the lake and wait for it to recede. When it does we must be first on the scene where the gold lies.”

“Good!” cried Nicodemus; “if they attack us there——”

“Then it will be time enough to retaliate!” declared Frank.

And so the matter was settled.

The Spectre sailed away across the arm of the lake and landed upon the summit of a small hill. It would have required several days’ journey for the Dooley gang to have made the circuit around by the shore.

So the aerial voyagers felt safe. But this new development had put a different face upon matters.

However, if the lake should again recede, the air-ship could easily cover the three miles to the mound of gold before the men on foot could.

Frank nor Nicodemus either cared for but a fair share of the treasure. But the unfair and unreasonable conduct of Dooley impelled them to seize the whole of it if they could.

Another day and night passed and yet the lake presented the same smiling and smooth appearance. But that afternoon a curious thing happened.

Barney, who was on deck, noted a curious yellow cloud rising from the west.

It mounted upward rapidly and soon had assumed angry proportions. The sun was hazy and the landscape took on a sickly appearance.

“On my word!” cried Frank, “it looks as if we were going to have another Andean storm.”

“Jericho!” exclaimed Nicodemus, “don’t say that. We had better anchor the air-ship hereabouts if that is true.”

All watched the cloud until the whole western sky was obscured. Then there was a distant rumble, lightning shot across the heavens.

The ground began to rock and pitch violently, trees and shrubs swayed and were bent to the ground, the air-ship was tossed about like a pebble, and no man could stay on his feet a moment.

“An earthquake!” gasped Frank.

“Bejabers, wud yez luk at the lake!” cried Barney.

All gazed in that direction and were dumfounded at the fearful spectacle presented.

The lake was like one mighty whirlpool, and went swirling about like a vast maelstrom. Its waters seemed to be receding every second.

Then the white sands of the shore line began to widen. Islands appeared in its surface.

The truth was plain.

The Transient Lake, impelled no doubt by the earthquake, was about to make one of its periodical disappearances.

Round and round swirled the waters. The ground had n............