As we have just stated, Hobson noticed that the solid ice, the ice-field properly so called, was only about one foot above the sea-level! We know that four-fifths of a floating mass of ice are always submerged. For one foot of an iceberg or ice-field above the water, there are four below it. It must, however, be remarked that the density, or rather specific weight of floating ice, varies considerably according to its mode of formation or origin. The ice-masses which proceed from sea water, porous, opaque, and tinged with blue or green, according as they are struck by the rays of the sun, are lighter than ice formed from fresh water. All things considered, and making due allowance for the weight of the mineral and vegetable layer above the ice. Hobson concluded it to be about four or five feet thick below the sea-level. The different declivities of the island, the little hills and rising ground, would of course only affect the upper soil, and it might reasonably be supposed that the wandering island was not immersed more than five feet. This made Hobson very anxious. Only five feet! Setting aside the causes of dissolution to which the ice-field might be subjected, would not the slightest shock cause a rupture of the surface? Might not a rough sea or a gale of wind cause a dislocation of the ice-field, which would lead to its breaking up into small portions, and to its final decomposition? Oh for the speedy arrival of the winter, with its bitter cold! Would that the column of mercury were frozen in its cistern! Nothing but the rigour of an Arctic winter could consolidate and thicken the foundation of their island, and establish a means of communication between it and the continent. Hobson returned to the halting-place little cheered by his discoveries, and found Long busy making arrangements for the night; for he had no idea of sleeping beneath the open sky, although Mrs Barnett declared herself quite ready to do so. He told the Lieutenant that he intended to dig a hole in the ice big enough to hold three persons—in fact to make a kind of snow-hut, in which they would be protected from the cold night air. “In the land of the Esquimaux,” he said, “nothing is wiser than to do as the Esquimaux do.” Hobson approved, but advised the Sergeant not to dig too deeply, as the ice was not more than five feet thick. Long set to work. With the aid of his hatchet and ice-chisel he had soon cleared away the earth, and hollowed out a kind of passage sloping gently down to the crust of ice. He next attacked the brittle mass, which had been covered over with sand and earth for so many centuries. It would not take more than an hour to hollow out a subterranean retreat, or rather a burrow with walls of ice, which would keep in the heat, and therefore serve well for a resting-place during the short night.