"It gives no sign of life."
"Not at present," answered the man of science. "But we have seen it move. It has appeared and disappeared. Consequently, it must have hidden machinery."
"Of course."
"So that we come to the conclusion, which is inevitable, that there must be a man or men inside to direct the ship."
"Hurrah!" cried our hero; "I didn't think of that. We are saved if that is so, and it must be as you say."
"Hum!" muttered the professor; "I don't know so much about that. If, when it makes a start, it glides along the surface of the water, we are all right; but if it goes down, we are lost."
"I've got an idea," said Mont, after a pause. "We must knock at the door, and see if we can find anyone at home."
His companions laughed.
"I have searched carefully," said Carl, "but I can't find even a manhole."
There was nothing to do but to wait until morning.