"It all depends," was his commander's rejoinder. "It depends upon the thickness of the ice above." 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. The result this time was the same. After ascending several fathoms, the submarine encountered ice and stopped. "Well, there is no help for it," said Lord Hastings. "We'll have to try and break through. Submerge to ten fathoms, Mr. Templeton." Jack repeated the command and the D-17 dived deeper. At the proper depth, the vessel's course was checked. Then Lord Hastings ordered that the craft be brought to the surface with as much force as possible. The water was sent from the tanks with a rush and the D-17 seemed to leap upward. A few moments later there was a violent shock and all aboard were thrown from their feet. The submarine had failed to break through. "Again!" cried Lord Hastings and gave the signal to submerge. A second attempt met with no better result and Lord Hastings immediately commanded a third trial. "We'll have to get through now or we'll probably drown," he said quietly. "I am afraid we have strained our seams. We'll need an overhauling immediately we put into Petrograd--if we are fortunate enough to get there." "And what do you suppose has happened to our periscope?" demanded Frank. "Oh, that has been smashed to bits before now," said Lord Hastings quietly. "However, we can rig up another one if it is necessary before we get to port." "All ready for the next trial, sir," Jack put in at this juncture. "We are down five fathoms." "All right. Let her go," replied his commander. This time the D-17 rose even more swiftly than before. Again there was a violent shock, followed by a crashing sound; and then the submarine floated clear. "Hoorah! We're up, sir," shouted Frank. "Don't crow too soon," was the reply. "We may be up, but there is no telling yet what condition we are in. We'll go on deck." Lord Hastings led the way and the two lads followed closely behind him.