Her pace within this narrow tunnel was scarcely a crawl, but no faster dared Haverly drive her, lest, through the sudden narrowing of the passage, she should collide with the ice.

Two hours dragged by, and still the eternal ice gleamed around them in dazzling monotony, and they grew sick of gazing upon its never-ending sameness. Mervyn alone knew no weariness.

Close to the glass he stood, his nervous hands clenching and unclenching as he gazed ahead.

Suddenly a glad cry pealed from his lips.

“At last!”

The ice tunnel had ended; the Seal had passed out into open water.

“Raise her,” roared the American down the tube. “I guess we’ve struck the Polar Sea!”

The scientist could scarcely control his eagerness as the submarine slowly rose. Back and forth he paced, as the tinge of the water without faded from deep green to grey. Then the dim light gave way to a flood of brilliant sunshine, and Garth switched off the searchlight, as the Seal emerged into the full glory of the Northern sun.

For here no leaden grey sky overhung the scene, but a pure blue vault of matchless brilliance, its beauty unmarred by a single cloud.

As, in response to Haverly’s signal, the engines stopped, Mervyn flung open the door, and a flood of bracing air poured into the turret.