"Then we are fast in the ice under water," spoke Andy after a pause.
"It looks like it," came from the inventor. "However we will not give up yet. We may be able to make our way out. Start the engine at full speed, Washington."
The machinery which the professor had shut down at the first cry of alarm was set going. Soon the throb and hum told that the big screw was revolving.
Meanwhile the Porpoise had regained an even keel, and had stopped sinking, remaining at the depth of seventy feet below the surface.
"We will first try to go straight ahead," said the captain.
He turned on more power and they all waited in anxiety. The test would tell whether they could escape in that direction or not.
But, though the powerful screw churned the water to foam in the tunnel, the Porpoise never budged. It was as if she was held in a vice.
"It's of no use," remarked Mr. Henderson with a shake of his head as he watched the speed gage and noted that it remained stationary. "We must now try the other way."
Once more the big screw was set going, this time in the opposite direction, so as to pull the ship out of the ice if it was possible. But this, too, was of no avail.
"It looks as if the ice had us," said Andy, trying to speak in a cheerful tone. "But there's one way more to try."