MECHANICAL DISRUPTION OF THE SEA ICE 191 



a considerable southern detour in order to avoid it. By the time that the party 

 reached the Drygalski Ice Tongue on November 29 long lanes of ojjeu sea were 

 spreading shorewards, deeply indenting the sea ice, and threatening to bring 

 about its entire disruption. By the time the party reached the surface of the 

 Larsen Glacier on Christmas Day it was seen that the whole of this sea ice had 

 broken away. 



At the time when the Western Party left Cape Royds in November 1908 a 

 slight glazing was noticeable on the northern faces of the snow-drifts on the sea 

 ice, and the sea ice just west of the Penguin Rookery at Cape Royds, particularly 

 where it was discoloured by a large amount of finely powdered guano swept off 

 the rookery by the spring blizzards, showed signs of rottenness. This thawing was 

 further encouraged perhaps by heat radiated from the black cliffs of kenyte rock. 

 From December 1, 1908, to January 24, 1909, we have no complete record of the 

 disintegration of the fast ice. Certainly heavy pack prevented access to Cape 

 Royds early in January, for the Nimrod on January 1 was held up in the pack at 

 Beaufort Island, and was unable to reach Cape Royds until January 5. On 

 January 7 she started away again to look for a lost party, and in a few hours she 

 was again jammed in the pack and nearly driven ashore at Horseshoe Bay. She 

 remained fixed in the pack till January 15, and was drifted across the Sound until 

 almost within sight of Granite Harbour. On January 24 the Nimrod picked up 

 the Western Party, who noticed that all the sea ice north of a line from the Chinese 

 wall of the Cape Barne Glacier, and passing westwards about a mile north of the 

 north end of Inaccessible Island, had gone out. By January 27 all the ice north 

 of Inaccessible Island had been removed, with the exception of that between Mickle 

 Island, the stranded berg, and Flagstaff Point, as well as a narrow fringe along the 

 coast to Cape Barne. This last was rapidly breaking up. AVhere facing a large 

 expanse of open water the fast ice usually broke off as long strips with a certain 

 amount of brash ice between. 



At Backdoor Bay the first stage of disruption manifested itself as a long crack 

 roughly parallel with the line of open water. The strip of ice between this crack 

 and the open water became later divided by a series of transverse cracks into 

 squarish blocks, and these gradually floated out under the influence of the ebb tide, 

 until they were caught by a surface current and soutlierly wind and carried round 

 Flagstaff Point northwards to join the main pack. As the thicker and older bay 

 ice was approached the disrupted squares became smaller and smaller, until finally, 

 on February 7, the thickest ice, covered with snow-drifts, broke into almost cubical 

 blocks and was removed, leaving the bare ice-foot. It was remarkable that the 

 blocks of this snow-covered ice frequently had projecting edges 1 or 2 feet 

 wide, either of snow alone or of ice alone. These were due to the fracture being 

 stepped instead of simply vertical, the line of fracture following for a certain distance 

 horizontally the junction line between the snow-drift and the sea ice. 



