The D-17 rose gradually; then, with a slight grating sound, she paused suddenly.

“Bumped it again,” said Frank.

Lord Hastings nodded.

“Must be quite an iceberg,” was Jack’s comment.

“Unless the sea is frozen over solidly for a considerable distance,” supplemented Lord Hastings.

“But that could hardly be,” protested Frank.

“Oh, yes, it could. It has happened more than once; and for that reason it may possibly happen—or have happened—again.”

“Then what is our next move, sir?” asked Jack.

“We’ll proceed under water a ways and then try again. If we don’t come up next time, we’ll try and force our way to the surface. We’ve got to get up for a look around, and the sooner the better. The ice is likely to grow thicker with each succeeding minute.”

Again the D-17 proceeded under water for perhaps half an hour and then Lord Hastings announced his intention of trying to rise.