“Don’t do it! Don’t do it!” exclaimed the professor in an excited whisper. “No one must go in that room. I forgot to tell you and Jack about it. No one must enter. It contains a secret!”
“I heard a strange noise and——” Mark began again.
“It could make no noise! It would be impossible for it to make a noise!” the professor exclaimed.
“I heard something,” the boy insisted.
“You were dreaming!” said the professor. “Now go back to bed, Mark, and don’t let this happen again. Remember, no one must enter that room unless I give permission!”
Somewhat crestfallen at the outcome of his investigations, but realizing that the professor could do what he wanted to aboard his own ship, Mark went back to bed. But he could not sleep. All the rest of the night he was wondering whether Mr. Henderson had some strange creature hidden aboard the Mermaid. He feared lest the old scientist’s mind might be affected and, in his wildness he had made some infernal machine that would, in time, blow the whole ship apart.
But tired nature asserted itself at last, and, weary with vain imaginings, Mark fell into a slumber. The next morning he awoke with a start from a dream that he was being devoured by an immense water snake.
He said nothing to the others about his night’s adventure, for, as it transpired, no one else had been awakened by his investigations. The professor did not refer to his conversation with Mark.
“There’s something queer going on aboard the ship this trip,” said Mark to himself. “But I guess it’s none of my business. Professor Henderson seems to know what he is doing and I guess I can trust him.”
He resolved to think no more of the strange noises and movements, and, for several nights thereafter he was not disturbed by them.