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 av that,” roared barney. “it’s a foine brain yez have!”

pomp made a dive for barney, but the celt dodged him.

there would have been a lively ruction between the two, however, but for frank, who checked them.

“hold on!” he cried. “none of that. we have too many serious matters on hand just now.”

so the two jokers refrained from any more of this sort of thing. all returned to the cabin.

bell was exceedingly uneasy.

“i think we made a mistake in coming on this expedition,” he said. “we have sacrificed our lives and gained nothing!”

“you cannot say that,” said von bulow. “i have gained many valuable discoveries for science.”

“which science will never get.”

“yet, if i die now, i shall not feel that i have thrown my life away.”

“i don’t see how you regard it in that light. my wife told me i would meet disaster. i had ought to have stayed at home.”

“shure ye had ought to,” said barney, bluntly.

“you don’t mean to insult me?” flashed the captain.

“bejabers, thot wud be impossible!”

“what do you mean?”

but frank put an end to the jar quickly.

“tut, tut!” he cried. “don’t let me hear anything of that kind. this is a poor time for quarreling!”

“i am sure,” said von bulow; “i think we are well fixed for the emergency before us.”

“so do i,” said frank; “the chances for our own escape are very good.”

“about one in a million,” said bell, sarcastically.

“at least we can preserve life for a good long period aboard the dart,” said von bulow. “we have provisions enough for a year, eh, frank?”

“i think so,” agreed the young inventor. “and much longer if we economize.”

“but we could never live a year in these close quarters on this artificial air,” growled bell.

this was the real horror of their situation. it was not at all unlikely that the chemicals would give out before many weeks.

it was liable to give out at any time, and then a horrible death by asphyxiation must be the result.

truly this was a dreadful thing to contemplate.

but frank compressed his lips tightly and went resolutely into the pilot-house.

as nearly as he was able to plan it, he started the dart in what he believed was a direct course out of the valley.

the boat shot onward through the water like an arrow.

miles were covered, but yet there was no indication that they were approaching a coast.

a week passed thus.

it was a period of anxiety, of mental worriment and of almost despair.

heretofore no thought had been given to the chemical generators, for had they failed it was always known that a supply of fresh air could be obtained by almost instantly rising to the surface.

but now that it seemed certain that the boat could not rise, all depended upon the efficacy of the generators.

thus far they had evinced no signs of giving out. yet there was the dreadful uncertainty.

in every other respect except that of buoyancy the dart seemed as seaworthy as ever.

she made rapid speed through the limitless waste of water, and her engines worked to perfection.

but it did not seem possible that the vessel could long proceed without coming to land in some direction.

yet there was the fatal possibility of traveling about in a mighty circle for an indefinite length of time.

the keenest outlook was kept, and the spirits of all on board the dart were much in the same channel.

there was the same strained, anxious feeling, the dreadful sense of uncertainty, the horror of impending death in an awful form.

barney was constantly at the wheel in the pilot-house, keeping the keenest sort of an outlook.

and one day there was seen to be a sudden change in the color of the sea water.

all noticed it with a thrill, and a great cry went up.

“we are coming to land!”

the peculiar greenish hue, and many significant changes in the character of the ocean bed would seem to indicate this to be a certain fact.

at once all became excitement.

everybody crowded to the windows and kept a lookout for—what they hardly knew, unless it might be some certain indication of land.

suddenly the dart came to a stop.

she was facing a succession of ascending reefs. further progress in that direction was barred.

but all were confident.

“i tell you we are close to land,” cried von bulow.

“we have only to ascend those reefs to reach it,” declared bell.

but frank reade, jr., was not so sanguine.

“we shall see,” he said. “put out the anchors.”

barney and pomp hastened to do this. the dart rested upon the verge of one of the reefs.

then preparations were quickly made for leaving the dart.

the diving suits were quickly on hand and all were soon in readiness.