“Because of lax discipline the ship was sent on fire.  We tried to put it out but could not.  The rest you know.”

“I heard them plan to capture this airship, but could do nothing to stop them.  Then I resolved to pretend to act with them.  They fear pursuit for their other mutiny, and are anxious to get as far away as possible.”

“Do you think they will abandon the ship in a little while?” asked the professor hopefully.

“I’m afraid not,” answered the mate.  “I think they want to get rid of all of you, so they can sail about as they please.  Tony is a smart man.  He could soon learn to run this ship, he thinks.”

“I doubt it,” Mr. Henderson answered.  “But how are you going to help us?”

“I have not fully made up my plans,” the mate answered.  “However I wanted you to know I would do my best to save you.  Now I must go.  Be on the watch and when I can I will let you know what I have decided on.  I will hand Mark a note when I bring your meals, just as I did to-day.  I think——­”

“Hark!  What was that?” asked the professor.

There was a noise outside the door, as if some one was listening.

“Put out the lights!” whispered the mate, and Jack switched off the electric incandescents.

A knock sounded on the door and the voice of Tony called: 

“Mark!  Come here!  I want you to look at the gas machine.  It has stopped working, and we are falling!”

CHAPTER X

 Fooling their enemies

Mark hurried into the corridor, taking care to close the door after him, so Tony could get no glimpse of the mate who had risked so much to save his friends.  But he need not have been alarmed for the leader of the mutineers was too excited over the stopping of the gas apparatus to give any heed to who was in with the captives.

“Do you think you can fix it?” he asked the boy.

“I guess so,” Mark replied confidently.  “If I can’t there is no danger, for we will fall gradually and land in the water.”

“But I don’t want to do that,” Tony objected.  “I want to keep on through the air.”

Mark did not reply.  By this time he was at the gas machine.  He soon saw nothing was the matter save that new material must be placed in the retort where the vapor was generated.  He refilled it, the gas was manufactured once more, and the ship began to rise.

“I will know how to do it next time,” Tony said with a grin.  Mark realized that every time he showed the leader of the mutineers something about the ship it was putting the professor and his friends more and more into the power of the scoundrels.  But there was no help for it.

The ship was still plunging ahead, and kept about a mile above the earth.  As there was no further need of Mark, he was told he could go back to his friends.  When he reached the room where they were held prisoners, he found the mate had gone away, promising again to do all he could for them.