AN UNPLEASANT SURPRISE
FORTUNATELY, there was spare clothing in plenty on board, and without delay all the officers and crew who had been on deck during the avalanche of water were able to change into dry kit.
For another three hours Captain Stormleigh kept the Polarity on a due easterly course, literally groping his way through the fog-bank.
Beyond glancing gently against an occasional growler, the ship escaped serious collision, and when the fog lifted an expanse of open water lay in front of her. Away, broad on the port beam, could be discerned the rugged outline of the giant berg which had so nearly proved to be the tomb of the Polarity and her crew.
"Five miles in length, and two hundred feet in height, at the very least," declared Travers.
"What causes an iceberg to form?" asked Guy.
"It's the seaward end of a glacier," replied the second mate. "Every year, as the temperature rises a few degrees, the mighty glaciers of the Arctic rid themselves of a few cubic miles of ice. These bergs, once they are afloat, drift southwards, gradually diminishing and toppling over, until they melt away."
"What causes them to topple?" asked Guy. "I know that, roughly, six-sevenths of a mass of floating ice is beneath the surface. It seems a lot to capsize."
"Normally six-sevenths of the bulk of a berg is underneath the surface," replied the second mate. "We may take it for granted that yonder berg is, since it has only recently taken up its present position. In that case, the berg is at least a quarter of a mile in depth. But the ice is constantly thawing in the water, although the part exposed to the air may not be. Consequently the melting process underneath proceeds until the berg becomes top-heavy, and then—well, you have just seen that specimen do a somersault."
For the next five or six hours all hands were kept busily employed in making good the damage which had been done by the destructive wave.