CHAPTER XIV

  MANY MILES BELOW

  "Don't be alarmed," spoke the calm voice of the professor. "I have onlyturned off the electrics. I want to switch on the search lights, to seeif we can learn anything about our position."

  As he spoke he turned a switch, and, the gloom below the ship, as theboys could see by glimpses from the floor-window, was pierced by adazzling glare. In the bottom of the _Mermaid_ were set a number ofpowerful electric arc lights with reflectors, constructed to throw thebeams downward. The professor had built them in for just this emergency,as he thought that at some time they might want to illuminate what wasbelow the craft.

  Not that it was of much avail on this occasion, for, though the lightswere powerful, they could not pierce the miles of gloom that lay belowthem. The beams only served to accentuate the darkness.

  "I guess we'll have to trust to luck," the professor said, after a vainattempt, by means of powerful glasses, to distinguish something. "Thereis too much fog and vapor."

  "What makes it so warm?" asked Mark, removing his coat.

  "Well, you must remember you are approaching the interior of the earth,"the professor answered. "It has been calculated that the heat increasesone degree for every fifty-five feet you descend. We have come downseveral hundred feet and of course it is getting warmer."

  "Then if we go down very far it will get so hot we will not be able tostand it," Jack put in.

  "I do not believe we will suffer any great inconvenience," Mr. Hendersonwent on. "I believe that after we pass a certain point it will becomecooler. I think the inner fires of the earth are more or less heated gasin a sort of inner chamber between two shells. If we can pass the secondshell, we will be all right."

  "But aren't we liable to hit something, going down into the dark thisway?" asked Mark.

  "We will guard ourselves as far as possible," the scientist answered.

  The _Mermaid_ seemed to be going down on a side of the immense shaft agood way distant from the strange waterfall. When they had first droppedinto the hole the travelers could hear the rush of waters, but now thenoise was not audible.

  "I think the hole must widen out the farther down we go," the professorsaid. "We are probably many miles from the fall now."

  "I'm sure I hope so," put in Jack. "It would be no fun to have to take ashower bath in this place."

  After a meal, the boys and the professor took some more observations,but with all their efforts nothing could be seen below the ship but avast black void, into which they were steadily descending.

  "I wonder when we're going to stop," asked Mark. "It's like playing thegame 'Going to Jerusalem,' you keep wondering when the music will ceaseand you will have a chance to grab a chair. I only hope we have a chairor something else to sit on, in case we go to smash."

  "We're not liable to have any accidents with the professor in charge,"Jack answered. "Didn't he bring us safe out of some pretty tight holeswhen we went to the north pole in the airship, and again when we foundthe south pole in the submarine?"

  "Yes, but this is different," objected Mark.

  "Well, I'm not worrying," Jack went on. "It doesn't do any good, andonly makes you lie awake nights. By the way, I wonder what time it isgetting to be."

  He looked at his watch and found it was close on to eight o'clock in theevening. So late had dinner been served, and so varied were thehappenings of the last few hours, that time had passed quickly.

  "Why it's almost bed-time," said Jack. "I wonder if we are to go ondropping into the depths of nowhere all night."

  At that moment the professor entered the room where the boys were. Heseemed quite pleased over something, and was smiling.

  "Everything is going along famously," he said. "I have just tested theair and find it is rich in oxygen. We shall suffer nothing on thatscore. The heat too, seems to have decreased. On the whole, everythingfavors us."

  "Are we going on down?" asked Mark.

  "As far as we can," Mr. Henderson answered. "Let me see how far we arebelow now."

  He went to the gage that indicated the vertical position of the ship.Because of the changed conditions, the craft now sinking below thesurface of the earth instead of rising above it, as was its wont, somecalculations were necessary. These the scientist made as quickly as hecould.

  "We are now ten miles underground!" he exclaimed. "That is doing verywell. My theories are working out. I think we shall land somewherebefore long."

  "I hopes so!" exclaimed Washington coming in at this point. "I'm mightyskeered shootin' down int' this dark hole, and no time-table t' showwhen we's due t' arrive."

  "We ought to land in a couple of days more," the professor answered."Never mind about worrying Washington, I'll take care of you."

  "I hopes so, Perfesser," the colored man said. "I got a little girlwaitin' for me back in Georgia, an' I'd like t' see her 'fore I gitburned up."

  Accompanied by the professor, the boys made a tour of the ship to seethat all the machinery and apparatus were in working order. Owing to thechanged conditions the negative gravity engine had to be worked atfaster speed than usual, since the downward pull of the earth wasgreater the farther they descended into the interior and they did notwant to fall too swiftly. But this was easily provided for, since theprofessor had made the apparatus capable of standing a great strain.

  The ten miles had become fourteen when the professor, finding thateverything was in good shape, proposed that the boys go to bed. They didnot want to, though they were sleepy, and they feared to miss somestrange sights.

  But when the professor had promised to call them in case anythingunusual developed, they consented to turn in, and Bill and Tom assumedtheir duties, which were light enough, now that the ship was merelyfalling into the immense shaft.

  When Mark turned into his bunk he could not go to sleep at once. It mayhave been the excitement over their new position, or because he hadeaten too hearty a supper, but the fact was he remained awake for sometime.

  While thus tossing restlessly on his bed, wondering what ailed him, hethought he heard a noise in the main apartment out of which thestoreroom opened. He crawled softly from his bed, and looked from hisstateroom door.

  In the light of a shaded electric Mark saw the figure of some one glideacross the floor and take refuge in the room, which Professor Hendersonalways was so particular about.

  "I wonder what or who that was," reasoned Mark. "There is some mysteryin this. Can the professor have concealed some one on this ship whosepresence he does not want to admit? It certainly looks so."

  Not wanting to awaken the ship's crew, and remembering what Mr.Henderson had said about any one entering the storeroom, Mark went backto bed, to fall into an uneasy slumber.

  "Breakfast!" called Washington breaking in on a fine dream Jack washaving about being captain of a company of automobile soldiers. "Lastcall for breakfast!"

  "Hello! Is it morning?" asked Jack.

  "Not so's you could notice it," Washington went on. "It's as dark as astack of black cats and another one throwed in. But breakfast is readyjest the same."

  The boys were soon at the table, and learned that nothing of importancehad occurred during the night. The _Mermaid_ had been kept going slowlydown, and about seven o'clock registered more than fifty miles below theearth's surface.

  Still there was no change in the outward surroundings. It remained asblack as the interior of Egypt when that country was at its darkest. Thepowerful electrics could not pierce the gloom. The ship was workingwell, and the travelers were very comfortable.

  Down, down, down, went the _Mermaid_. The temperature, which had risento about ninety went back to sixty-nine, and there seemed to be no moredanger from the inner fires.

  They were now a hundred miles under the surface. But still the professorkept the _Mermaid_ sinking. Every now and again he would take anobservation, but only found the impenetrable darkness surrounded them.

  "We must
arrive somewhere, soon," he muttered.

  It was about six o'clock that night that the alarm bell set up a suddenringing. The professor who was making some calculations on a piece ofpaper jumped to his feet, and so did a number of the others.

  "We are nearing the bottom!" he cried. "The bell has given us warning!"