"Skis," explained Ranworth. "It proves pretty conclusively that the party found the ordinary Canadian pattern of snow-shoes more satisfactory. They took plenty of both, I know; so they utilised the skis for landmarks to guide them on their return journey. Another half an hour ought to bring us within sight of Observation Camp. Steady, Leslie," exclaimed Ranworth a few minutes later. "We're approaching another difficult patch. Ease her down a bit and stand by to put her on the decapods."
The warning was necessary, for the Bird of Freedom was about to cross the track of a former glacier.
Centuries previously, a river of ice wended its slow journey to the sea; but, possibly owing to a volcanic disturbance, the path of the glacier was diverted in a different direction. The "scour" could be seen clearly, while the bed was encumbered with boulders of all sizes, deposited there with the melting of the cut-off portion of the glacier.
Fortunately the irregularities between the various sized stones had been partly filled up with frozen snow, so that, by use of her decapod wheels, the Bird of Freedom could surmount the rough ground with but little difficulty.
On the far side, a ridge of gaunt rocks had to be avoided, necessitating a detour of nearly a quarter of a mile.
This done, Leslie was about to transfer the power to the twin aerial propellers, when Guy exclaimed:
"Look! There's a snow-squall bearing down ahead."
Even as the approach of a squall at sea can be detected by the peculiar ruffling of the water, so was the approach of the snowstorm marked by a darkening of the glistening expanse of white; while, like a deep-greyish, ill-defined cloud, the forefront of the blizzard whirled rapidly upon the Bird of Freedom.
Well it was that the sleigh had a firm grip by means of the decapod wheels. Had she been supported solely by her runners, there was a great possibility of her being swept at a breakneck speed before the well-nigh irresistible gusts.
The whole fabric of the sleigh quivered as the snow-squall struck it. In less than ten seconds the observation scuttles exposed to the direct force of the wind were completely obscured with snow.