SEASONAL DISTRIBUTION OF THE ICE-EDGE 293 



ice lay well outside the South Shetlands, but in some other years (e.g. 1908, 1912, 1913, 

 1922 and 1924) some factory ships entered the Bransfield Strait without hindrance. The 

 ice conditions are variable here, but it seems that the edge more often than not lies 

 outside the South Shetlands in November. In the exceptional spring of 1930 ice was 

 still to be found to the east and a little to the north of South Georgia, but in other years 

 it lay considerably farther south. East of 20 W the records are well distributed, and the 

 normal position of the ice-edge is fairly clear to 120 E. In the Adelie Land, Ross Sea, 

 and Western Pacific regions there is little to go on, but a useful observation was made in 

 1928 in i70°E (Plate LXXVIII). In the Eastern Pacific sector (Plate LXXIX) the 

 'Discovery II' found ice in November 1934 about 66° S. 



DECEMBER (PLATES LXXX-LXXXII) 



There is a wealth of data for this month. In the region south of South Africa rapid 

 changes take place, and large tracts of pack begin to break up and melt. The South 

 Shetlands are usually clear of ice. Between 30 W and about 30 E the ice-edge is still 

 in a low latitude, but warmer water farther south causes the central part of the ice belt 

 to break up, leaving an outer zone which also begins to disintegrate. Hansen (1934), 

 writing of this region, says: " . . .from December onwards the [whaling] expeditions 

 force their way southwards through the pack-ice until they emerge into comparatively 

 open water round about 6o° S. The more continuous pack-ice is seldom met with then 

 until the zone of the pack-ice along the land is reached. There are thus two zones of 

 pack-ice when the season has advanced as far as this: an inner zone along the land, 

 drifting westwards, and an outer zone drifting eastwards.. . .At about the turn of the 

 year the outer zone of pack-ice, at any rate the portion of it which lies to the east of the 

 South Sandwich Islands, disappears (melts). Before melting, the zone of pack-ice 

 usually breaks up in several places, with the result that it divides into large drifting 

 islands of pack-ice." 



Plates LXXX and LXXXI give a fairly clear indication of the conditions as far as 1 io° E. 

 The two zones described above are not found east of 40 E, but there is a considerable 

 retreat to the south and it will be seen that the more northerly observations are generally 

 near the beginning of the month, and the more southerly towards the end. We have no 

 records between no° and 150 E, but there are several observations in the Ross Sea, 

 some of which are derived from the Antarctic Pilot (1930, pp. 151, 152). Here conditions 

 are rather variable, but it is well known that a ship penetrating the ice belt at this time of 

 year will normally find open water in the southern part of the sea. The 1841 record in 

 148 W is probably farther north than the normal. There are no data from the Pacific 

 sector except in the Bellingshausen Sea where the ice now lies well to the south. 



JANUARY (PLATES LXXXIII-LXXXV) 



The Bransfield Strait is now clear of ice, and much of the west coast of Graham Land 

 may be free. Conditions are uncertain in the Weddell Sea, but streams of heavy ice may 



