CHAPTER XI

  MYSTERIOUS HAPPENINGS

  The voice of the mate echoed through the _Mermaid_. Those on deck heardit, as did Tony in the engine room, where he was vainly trying tounderstand the complicated machinery.

  An instant later there sounded from beneath the ship a series ofsplashes. More sailors were leaping from the deck of the craft to theocean. The distance was not great, particularly as they all landed inwater.

  "Quick!" cried the mate to a group of sailors that hesitated beforetaking the jump. "The ship may blow up any minute now."

  The men needed no second urging. As soon as they struck the water theybegan to swim ashore, as it was not far away. One after another theyjumped over the rail. Tony was the last to go. He urged the captives tofollow him, but they all refused.

  A minute later the only one of the pirate crew left on the ship was themate. The others were all struggling in the sea. Eventually they allreached shore in safety.

  The airship was now within about twenty feet of the water. It was stillfalling but not so rapidly.

  "Better send her up, now," said the mate to Mark, and the boy turned thenecessary levers to accomplish this.

  Dipping into the water as a sea gull does when searching for food on thewing, for she had come quite low, the _Mermaid_ mounted once more intothe air, and was soon sailing along over the heads of Tony and his gang.

  "What's it all about?" asked Mr. Henderson, who seemed in a sort ofstupor. "I thought the ship was broken. How, then, can it rise?"

  "It was only a trick of mine," Rodgers said. "The gas machine is notbroken. I had Mark fix it so that only a little vapor would begenerated. When the supply in the holder was not enough, and no more wasbeing made, the ship had to sink. Mark and I pretended it was worse thanit really was just to scare the scoundrels."

  "And you evidently succeeded," observed Mr. Henderson. "They have allleft us. I am glad you stayed."

  "So am I," said Rodgers. "I was just waiting for a chance to escape fromthat crowd. This was the plan I thought of that night. I wanted to seethe men put on some island where they could manage to live, and whichwas not too far away."

  The _Mermaid_ was now mounting upward rapidly, as Mark had adjusted themachinery properly. The craft was well rid of the pirate crew, and wasable to proceed on its way, and enable Mr. Henderson to carry out hisplans.

  When the _Mermaid_ had reached a certain height her prow was turned theother way, and she was sent back racing over the ground she had justcovered. But now the ship was in the hands of friends. Fortunately nogreat damage had been done by the sailors, and the professor was soonable to get things in ship-shape. The engines had not been molested andwere working better than ever.

  "Now to make another attempt to reach the big hole in the earth," theprofessor cried. "We will be careful next time, who we rescue from shipsat sea."

  The island was soon left behind, becoming a mere speck on the ocean.Those aboard the _Mermaid_ knew no harm could befall the sailors, asthere were no savage tribes on the little spot of land. Eventually thesailors were picked up by a passing vessel and taken to their homes. Thestory of their first mutiny leaked out and they were properly punished.

  It required several days travel before the airship regained the distanceshe had lost because of the plans of the pirates. Also, there were anumber of minor repairs to make, and the professor and his friends werekept busy.

  "How much longer before we come to the big hole?" asked Jack, one day.

  "I think we ought to be near it in about two weeks," the professorreplied. "I only hope we shall not be disappointed, and will be able toexplore it."

  "'Tain't goin' t' be no fun t' be decimated an' expurgitated inter aconglomerous aggregation of elements constituting th' exterior portionof human anatomy," said Washington in dubious tones.

  "You mean you're afraid of being boiled in the steam from the big hole?"asked Mark.

  "Jest so," replied the colored man.

  "You don't need to worry about that," put in the professor. "I will nottake the ship down if there is any danger, though of course there willbe some risk."

  The ship, having been fully repaired, was now able to be speeded up, andwas sent scudding along toward her destination. Rodgers proved avaluable acquisition toward the crew, for he had sailed many years inthe waters over which they were flying, and was able to give theprofessor many valuable hints. He had heard vague stories of the islandwith the big hole, but had never been near it. He did not make the triphowever, as, at his request, he was put off at an inhabited island onenight.

  It was about a week after the sailors were frightened from the ship,that a curious experience befell Mark. Washington was on duty in theconning tower, attending to the apparatus as the ship flew through theair, and all the others had gone to bed. Mark had remained up, laterthan the others as he was interested in reading a book on science.

  About ten o'clock he became hungry, and going to the pantry got somebread and cold meat. He set these on a table, and then, remembering hewould need some water to drink, started after some in the cooler, whichwas in a little room near the tower.

  Washington heard the boy as he turned the faucet to draw the liquid, andspoke to him, as the colored man was rather lonesome at his post. Markdid not linger more than a minute or two, but when he returned to wherehe had left the food he was much surprised.

  There was not a trace of it to be seen. The dishes were on the table,but every vestige of bread and meat had disappeared.

  "I wonder if a cat or dog has been here," was Mark's first thought. Thenhe remembered that no such animals were aboard the _Mermaid_.

  Something on the floor caught his eye. He stooped and picked it up. Itwas a slice of bread, but in such shape that the boy stared at it,puzzled as to how it could have become so.

  It was flattened out quite thin, but the strangest part of it was thatit bore what seemed to be the marks of thumb and fingers from a verylarge hand. So big, in fact, was the print, that Mark's hand scarcecovered half of it, and, where the bread had been squeezed into a puttylike mass (for it was quite fresh) the peculiar markings on the skin ofthe tips of the fingers were visible.

  "It looks as if a giant grabbed this slice of bread," Mark observed."There are strange happenings aboard this ship. I wish I knew what theymeant."

  He looked all around for the food, thinking perhaps a rat had dragged itoff, but there was no trace of it.

  Suddenly the boy thought he heard a sound from the big storeroom. He wasalmost sure he heard something moving in there. He started toward thedoor when he was stopped by hearing the professor's voice call:

  "Don't open that door, Mark. Have I not told you that place must not beentered?"

  "I thought I heard some one in there," Mark replied.

  "There is nothing in there but some apparatus of mine," Mr. Hendersonsaid. "I want no one to see it. What is the matter?"

  Mark explained matters to the scientist, who had, as he said later,arisen on hearing the boy moving about.

  "Oh, it was a rat that took your stuff," Mr. Henderson said. "I guessthere are some pretty big ones on the ship. Get some more food and go tosleep."

  Mark felt it best to obey, though he was by no means satisfied with theprofessor's explanation. He listened intently to see if any more noisescame from the storeroom, but none did, and he went to bed.

  Several times after that Mark tried the experiment of leaving foodabout. On each occasion it was taken.

  "It looks as if the ship was haunted," he said. "Of course I know itisn't, but it's very queer. They must be strange rats that can get foodfrom shelves when there is only the smooth side of the ship to climbup," for on some occasions Mark had tried the experiment of putting thefood as nearly out of reach as possible.

  It took several nights to learn all this, and, as he did not want totake any one into his confidence, he had to work in secret. But, withall his efforts he learned nothing, save th
at there was something oddabout the ship that he could not fathom.

  At first he believed the professor had some strange animal concealed inthe storeroom, but he dismissed this idea almost as soon as he thoughtof it. For what could the scientist want with an animal when they weregoing to the interior of the earth? That some beast had slipped aboardwas out of the question. Mark was much puzzled, but finally, decidingthe matter did not concern him a great deal, gave up trying to solve themystery, at least for a time.

  The ship was now in the neighborhood of the equator and the climate hadbecome much warmer. So hot indeed were some nights that they slept outon deck, with the _Mermaid_ flying through the air at a moderate pace,for it was deemed best not to go at any great speed after dark.

  One night the professor, after consulting various charts and maps, andmaking calculations which covered several sheets of paper announced:

  "We should sight the mysterious island to-morrow."

  "That's good news!" exclaimed Jack. "I'm anxious to see what's belowinside of that big hole."

  "Everybody git ready for their funerals!" exclaimed Washington in a deepvoice. "I ain't got many----"

  "Cheer up," interrupted Jack, poking Washington in the ribs. The coloredman was very ticklish, and he began to laugh heartily, though, perhaps,he did not feel like it.

  Suddenly, above the sound of his shouts, there came a crashing, grindingnoise from the engine room.