However, Mr. Henderson felt his first duty to be toward his fellowmen, even if his voyage must be delayed, or given up for a time, while he got more provisions.  There would be no sleeping quarters for the sailors, but when this was explained to them they cheerfully said they would sleep on deck if necessary.  In fact some of them had to, but as the weather was warm and clear this was no hardship.  A few found quarters in the engine room and other apartments of the Mermaid.

Finding, after an examination, that his ship was in good order save for the broken gas apparatus, Mr. Henderson gave orders to proceed along the surface of the ocean.  The sailors wanted to see how it felt to mount into the air, but Mr. Henderson, refused to attempt a flight until he had made complete repairs, and this would take a day or more.

At this there appeared to be some discontent among the survivors, and they muttered to each other as they stood in a group on deck.  But the professor and his assistants were too busy with their preparations for fixing the break to notice this.

While the men were gathered in a knot near the after part of the small deck, the mate separated from them, and, coming close to where Mark was standing, unscrewing some of the broken parts of the pipe said, in a low voice.

“Tell the captain to watch out.”

“What do you mean?” asked Mark quickly.

“Hush!  Not so loud!” the mate exclaimed.  “If the men hear me talking to you, or see me, they may kill me.  Tell the captain to look out; that’s all.  Be on guard, and watch the engine room carefully.”

“But why—­ ?” Mark began, when, turning suddenly, the mate left him.  It was well he did so, for, at that instant, one of the sailors, who had observed the two conversing, strolled in their direction.

Much alarmed, Mark sought Mr. Henderson and told him what he had heard.

“I suppose the fire may have turned the poor man’s head,” the scientist said.  “I wonder if he thinks the men I rescued would mutiny and take possession of my ship?  If they did they would not know how to work it, so what good would it do?”

“Hadn’t we better look out?” asked Mark.

“I’m not afraid,” replied the professor.  “I will be too busy the next few days, repairing the break, to think of anything else.  Besides, what would they want to harm us for?  Didn’t we save their lives?”

Seeing the scientist placed no faith in what the mate had said, Mark went back to his task.

It soon became too dark to work, and it was decided, after supper, to halt the ship until morning as it would be less risky.

Mark did not sleep well, his dreams being disturbed by visions of pirates and black flags.  But morning came and nothing had developed.  The men seemed to recover their spirits with daybreak, and mast of the crew, after breakfast, greeted Mr. Henderson pleasantly, and asked to be allowed to help fix the ship.