The occupants of the fort had plenty to amuse them in the long days of compulsory confinement. They went on improving the inside of the various buildings, and dug trenches in the court to carry away the rain-water. Mac-Nab, a hammer in one hand and a nail in the other, was always busy at a job in some corner or another, and nobody took much note of the tempest outside in the daytime; but at night it was impossible to sleep, the wind beat upon the buildings like a battering-ram; between the house and the cape sometimes whirled a huge waterspout of extraordinary dimensions; the planks cracked, the beams seemed about to separate, and there was danger of the whole structure tumbling down. Mac-Nab and his men lived in a state of perpetual dread, and had to be continually on the watch. Meanwhile, Hobson was uneasy about the stability of the island itself, rather than that of the house upon it. The tempest became so violent, and the sea so rough, that there was really a danger of the dislocation of the ice-field. It seemed impossible for it to resist much longer, diminished as it was in thickness and subject to the perpetual action of the waves. It is true that its inhabitants did not feel any motion, on account of its vast extent, but it suffered from it none the less. The point at issue was simply:—Would the island last until it was flung upon the coast, or would it fall to pieces before it touched firm ground? There could be no doubt that thus far it had resisted. As the Lieutenant explained to Mrs Barnett, had it already been broken, had the ice-field already divided into a number of islets, the occupants of the fort must have noticed it, for the different pieces would have been small enough to be affected by the motion of the sea, and the people on any one of them would have been pitched about like passengers on a boat. This was not the case, and in his daily observations Lieutenant Hobson had noticed no movement whatever, not so much as a trembling of the island, which appeared as firm and motionless as when it was still connected by its isthmus with the mainland. But the breaking up, which had not yet taken place, might happen at any minute.