We were by no means certain that the motion of the floes would not even now prove a serious obstacle. Even as late as January they were heard roaring and crushing in the darkness to seaward, and their pressure forced our protecting floeberg somewhat shoreward, cracking and buckling up the floes, and heeling the ship over four degrees. For months, however, little sign of motion had been apparent except at tidal periods, when it sometimes came with curious suddenness, as if the tide wave had all at once overcome the resistance of the ice that bound it. For example, the morning of the 12th of March was beautifully calm and still, and few but those whose special duty it was knew that a high tide was due that day. I was engaged picking out some stones grooved and scratched by ice-motion from an overturned “floeberg” not far from the ship, when suddenly a curious faint sound came from the north-west, at first a dull, indistinct hum, but in a moment it grew nearer and louder, like the rush of a railway train. Then, as it swept down along the beach, the ice cracked visibly in every direction with a sharp rattle like musketry, and a loud rush of water under the floes came so suddenly and unexpectedly that I ran to the top of the berg with a vague idea that the ice was breaking up. But in a moment the tide wave had passed off to the south-west, and all was still again. CHAPTER VIII. The Sledging Campaign Opens—A Push for the “Discovery”—Petersen Breaks Down—Shelter in a Snowdrift—Difficulties in Retreat—A First of April Chase—Programme of Spring Sledging—Limited Hopes—Departure of Main Detachments—Double Banking—The Camp—A Night in a Tent—A Typical Floeberg—The Hare’s Sanctuary—Coat of Arms—Castle Floe—Parhelia—Road-finding in the Fog—Mirage—A Crevasse. The failure to communicate with H.M.S. “Discovery” in the autumn had to some extent disarranged our plans. Communication was absolutely necessary to ensure co-operation, and the sooner it was effected the better, for our consort had as much sledging work to get through as she could possibly complete in the season. Robeson Channel had to be crossed, and the rugged northern shore of Greenland explored in search of land poleward. Petermann’s Fiord had not yet been traversed, and Lady Franklin Sound might possibly open northwards, and afford a favourable route for the “Discovery’s” sledge-crews to penetrate as far as the shore of the Polar Sea.