Frank Reade, Jr., was greatly puzzled at this very singular action of the pneumatic valve.

“What is the matter?” he exclaimed in sheer astonishment. “Something is wrong somewhere.”

He went hurriedly below and examined the electrical apparatus.

It seemed to be all right.

Then he went into the tank-room and instantly saw what was the matter.

It gave him a shock.

The outer lining of the tank had become perforated, and water had flooded the forward compartment.

This was of sufficient weight to hold the boat in suspension.

It could be sunk by letting water into the tank as usual.

But though the tank was emptied as readily as usual, it was not sufficient in buoyancy to carry the boat to the surface.

In other words, the extra water in the forward compartment overcame this needed buoyancy and held the Dart in suspension.

It was most unfortunate that the water had invaded this part of the boat.

Frank was bathed in a cold perspiration. He knew that it was impossible to expel this water by any ordinary means.

It would be necessary for the Dart to reach the surface in order to do this.

As matters stood then the submarine boat would never be able to reach the surface again. It was buried forever at the bottom of the sea.

Confronted by this almost appalling truth, Frank Reade, Jr., stood aghast.

Not until footsteps sounded in his ears did he recover.

The other voyagers had come down to join him.

“Well, Frank, have you found out what is the matter?” asked Von Bulow.

“Yes,” replied the inventor.

“What?”

“We are lost!”

“Lost?”

“Yes; buried forever at the bottom of the ocean. Truly lost in the great Atlantic Valley!”

Stupefied with horror at these words, the others were for a time unable to speak.

Then Frank proceeded to explain the situation exactly.

It was a terrible truth.

“Great Heaven!” exclaimed Captain Bell; “then the Dart can never again reach the surface!”

“Never!”

“And we must die in these depths?”

“We won’t say that,” said Frank, resolutely. “The Dart will never return to the upper world, but I shall try and devise a method by which we may.”

With this the young inventor went into his own cabin.

He was in earnest in his purpose. A hundred different plans occurred.

With their bearings lost he knew not what direction to take to reach the upward slope of the shore of some island or continent.

If this could be done there would be a chance for escape, as they could leave the Dart, and in their diving suits stand a good chance of reaching land.

But the quest for the land must be a random one.

In such a vast space they might cruise about for months, possibly for a lifetime, without chancing to reach shore.

Every possible expedient to reach the upper air was considered by Frank.

But he could think of no better plan than to attempt the random quest for a shore.

He consulted with the others.

“That seems the only logical plan,” he said. “We may succeed very quickly and we may not.”

“I think we had better adopt it,” said Captain Bell.

“But what a pity that we should be obliged to leave this wonderful invention behind us.”

“Never mind that,” said Frank.

“I suppose you can build another one.”

“If I do I shall provide for the contingency which has just arisen.”

“Begorra, it was the earthquake shock that did it,” declared Barney. “Shure, it was enough to break anything.”

“I agree with you there, Barney,” agreed Frank.

But Pomp, who had been listening with interest, now came forward.

“Shuah, now, yo chillun hab not got de right plan,” he declared. “Jes’ yo’ heah what dis chile hab to say.”

“Well, Pomp,” said Frank; “what is it?”

“If yo’ wants jes’ to git to de surface why don’t yo’ swim?”

“Swim?”

“Yas, sah! Dat am a berry easy mattah. Jes swim up!”

Everybody looked at Pomp in surprise for a moment, and then laughed.

“I am afraid your plan is not the best kind of a one,” declared Frank. “It would be of little use to gain the surface and have no ship there to pick you up, or be out of sight of land. I am afraid you would come down for a permanent thing.”

Pomp looked somewhat aggrieved, at which Barney began to jolly him.

“Begorra, yez are a ganius, naygur!” he cried, hilariously. “Shure, yez take the cake. That’s a foine plan yez have!”

Pomp was angry.

“Shut up, yo’ no ’count I’ishman!” he cried, indignantly. “Yo’ amn’t got no plan fo’ to propose at all.”

“Bejabers, I’d rather not have thin to put out the loikes a............