"What is that?" asked Mr. Henderson.
"If we were in the air ship we could go up," replied the old hunter. "But, as it is, we had better go down. Why don't you fill all the water tanks, and try to sink beneath the iceberg? It can't go down so very far into the water, and I reckon we could slip under it."
"The very thing!" exclaimed the professor, whose mind was too sorely troubled over the happening to enable him to think of plans of escape. "That's the best thing to do."
Under the inventor's direction Washington filled the tanks and then, ere the pumps had ceased working, the screw was started and the deflecting rudder inclined to cause the ship to dive.
One, two, three minutes passed, and still the Porpoise did not move toward the bottom of the sea. She remained submerged and stationary. Anxious eyes gazed at the dials. The indicating hands trembled under the throbbing of the engines, but did not move.
"It will not work!" exclaimed Mr. Henderson in sorrowful tones.
"What does it mean?" asked Bill, who had come up to where the others stood.
"It means that we are prisoners in the ice; caught between the upper and lower parts of a gigantic berg, and held here under the water."
"Can't we ever get out?" asked Jack, a tremor coming into his voice. "Can't we escape when the ice melts?"
"The ice of the southern polar sea seldom melts in this latitude," replied the professor.