The race was on!

Her secret service days over for the present, the “sub” had been given a coat of black paint.  Now, as she scudded through the dark waters of Behring Sea, Dave, standing in the conning-tower, thought how much she must resemble a whale.  During the war many a leviathan of the deep had met death because he resembled a submarine.  Now, in peace times, in this feeding ground of the greatest of all prey, the tables might be turned, the submarine taken for whale.

The race was on.  Across Behring Sea they sped through foam-flecked waves and driving mists.  Pausing only a day at Nome, they pushed on past Port Clarence, rounded Cape Prince of Wales, and entered boldly into the great unknown, the Arctic Ocean.  A million wild fowl, returning to the Southland, shot away over their heads.  Here and there they saw little brown seals bob out of the water to stare at them.  Once they ran a race with a great white bear, and again they sighted a school of whales.  They gave these a wide berth, for should they grow friendly and mix their great flippers with the sub’s propeller, trouble would follow.  Walrus, too, were avoided, for they had a playful habit of bumping the under-surface of any craft they might chance to meet.

At last, far to the North there appeared a glaring white line.  They had reached the ice.  Their days of merry sailing on the surface were well-nigh over.  From this time on life would be spent in stuffy, steel-lined, electric-lighted compartments.  But for all that, it would not be so bad.  Openings in the floes would offer them opportunities to rise for a breath of fresh air, and dangers seemed few enough, since the ocean everywhere was deep, and ice-bergs, sinking dangerously to a great depth below the surface, were few.  Only the piles of ice and great six-foot-thick pans would make a white roof to the ocean, which was not without its advantage, for here the water would always be delightfully calm.

Shutting off the engines, dropping the funnel, closing the hatch, they sank quickly beneath the water’s surface, and were soon passing below a marvelous panorama of lights and shadow.  Through the thick glass of the observation windows there flooded tints varying from pale-blue to ultramarine and deep purple.  No sunset could vie with the color schemes that kaleidoscoped above them.  Here a great pile of ancient ice gave the whole a reddish tinge; and here a broad pan of transparent new ice cast down the deep-blue of the sky; and again a thicker floe admitted a light as mellow as expert decorators could have devised.

“It’s wonderful!” murmured the Doctor.

CHAPTER VII

A STRANGE PEOPLE

Ten hours after the start of the submarine, Dave Tower’s eye anxiously watched the dial which indicated a rapidly lessening supply of oxygen, while his keenly appraising mind measured time in terms of oxygen supply.  They were still scudding along beneath that continuous kaleidoscopic panorama of green and blue lights and shadows, but no one noticed the beauty of it now.  All eyes were strained on the plate-glass windows above, and they looked but for one thing—­a spot, black as night itself, which would mean open water above.