As the Doctor and Dave stood on deck watching the casting off of the ropes, the Doctor spoke of his plans.

“We may have lost the race,” he remarked rather grimly, “but we’re going to the Pole just the same.  It will mean something to you boys, at least, to be able to say that you’ve been there.  It was my purpose to lay our course directly for the Pole without establishing a base, but since we have been carried out of our way so far, and have used so much fuel, I feel that it will be wise to head for the farthest-north point of Alaska—­Point Barrow.

“I was assured, in Nome, that there were two oil-burning whalers wintering near there, and I have no doubt that we can depend on them for extra fuel.”

The hatches were lowered, the submarine sank from sight amid the “Ah-ne-ca’s” and “Mat-na’s” of the awe stricken natives who lined the cliffs a half-mile away.  The sub, with all on board, was again on its way to enter the race for the Pole.

“The race is on,” said Dave.

“I wonder?” smiled the Doctor.

Three times they rose in dark waterways for air.  The fourth time it seemed they must be nearing land—­

Yes, as the submarine bumped the edge of an ice-floe, a point of land showed plainly to port.

Dave, with field-glass in hand, sprang to the nearest ice-cake, then climbed to a pinnacle to take an observation.

“Clear water to the left of us,” he reported.

“Too close ashore?” asked the Doctor.

“I think not,” was Dave’s answer.  “We’ll have to submerge for three or four miles; then we’ll be clear of the ice.”

Signal bells clanged, and again they were gliding under the ocean’s armor of ice.

As he listened to the hum of the machinery, one question puzzled Dave.  He had seen something along the end of that ice-floe.  What was it?  A sail?  If so, it was a very strange one—­half white and half black.  He could not be sure it was a sail.  But what else could it have been?

But now they had swept out from under the ice.  It was time to rise.  Instantly he pressed the button.  The craft slowed again.  Another press, and as before they rose.  This time no white surface would interrupt them.  A current coming from land caught them forward and tilted the craft.  She slanted from fore to aft.  This did not matter; she would right herself on the surface like a cork.

But what was this?  As the point shot from the water, something rang out against the steel.  This was followed immediately by what, in the narrow apartments, amounted to a deafening explosion; then came the sound of rushing waters.

“Great God!  We’re bombed!” shouted the Doctor.

Dave’s cool head saved them for the moment.  His hand seized an electric switch and he pulled it desperately.  The bow compartment was quickly closed, checking the rush of water into the rest of the “sub,” Fortunately, no one had been forward at the time.