"I—I can hardly say," replied Jack. "Of course I don't believe in ghosts, but this—"
"It was probably a mist from the ocean," interrupted the professor. "Don't let me hear any more of it. Washington, go below. Your watch is up and Jack will take charge. I don't believe there will be any more ghosts."
Nor were there that night. The Porpoise glided along, requiring little attention, and when morning broke was several miles nearer the southern pole.
The journey was continued beneath the waves and it was found much cooler under them than upon the surface, for the ship was in the midst of the equatorial heat.
About four o'clock in the afternoon, when all was quiet aboard, there came a sudden yell from the engine room. Washington's voice could be heard calling for help. Then it died away in a groan.
"Something has happened!" called Jack. "Washington is in trouble."
He hurried toward where the machinery could be heard buzzing. The professor, with Andy and Mark followed. They expected to see the colored man caught in some shaft or belt, but he was nowhere in sight.
"Perhaps he has fallen into the ocean," suggested Mark.
"The engine room does not open into the sea," answered the professor.
A deep groan came from some corner of the engine room.