350 DISCOVERY REPORTS 



came to the South Orkneys in early February 1903 the whole of the south coast of 

 Laurie Island seems to have been blocked by pack-ice, and from the appearance of the 

 ice-foot in Scotia Bay when she at length anchored there on March 25, there was a 

 strong suggestion that the ice had but recently broken away. 



Mossman, basing his information on the data for 1903-14, states that Scotia Bay is 

 closed with compact ice for an average of 177 days in the year, the periods varying from 

 272 days in 1904 (actually 1904-5, since the bay did not open until February 6, 1905), 

 to only 52 days in 1908. In 1911, 1918 and 1919, according to Rudmose Brown ,1 the 

 bay was blocked for periods of less than three months, in 1920 for as long as eight 

 and a half. 



Although the opening and closing of Scotia Bay has now been observed for more than 

 thirty years, the period during which a single bay is blocked should not be accepted 

 unreservedly as an index of the ice conditions for the group as a whole. The envelopment 

 of the group, far from being instantaneous, tends to take place gradually, the eastern 

 portion as we have seen sometimes being liable to earlier blockage than the western, 

 with the result that any one bay, particularly on the south coast, may become blocked, 

 while the rest of the group, for the time being at any rate, is comparatively ice-free, and 

 vice versa. On April 2, 1934, the 'Discovery 11' found both Washington and Lewth- 

 waite Straits rather heavily packed up, the ice apparently being up to Laurie Island and 

 blocking Scotia Bay, but Signy Island and the whole of the south and west coasts of 

 Coronation Island, and probably the north coast as well, were surrounded by open 

 water. Other instances might be mentioned. Thus the congestion of any particular bay 

 or strait need not necessarily be an indication that the group as a whole is similarly con- 

 gested, although it does mean no doubt that sooner or later it will be. And so too 

 with the dispersal of the pack. In the comparative shelter and constricted space of the 

 bays and straits the ice tends to cling a little longer, especially on the southern side of 

 the islands, while elsewhere the main body of the enveloping pack is dispersing and 

 much of the group is comparatively ice-free. Following the severe winter of 1904 the 

 'Uruguay', after a quick passage through the ice, reached the South Orkneys on 

 December 31, and finding open water on the northern side of the group was able 

 to drop anchor in Uruguay Cove. When she sailed again the following day Scotia Bay 

 was still frozen over with fully two miles of firm ice intervening between a strip of open 

 water to the southward and the head of the bay. It was actually over a month later 

 before this ice-sheet finally broke up. 



A valuable summary of the ice conditions in the neighbourhood of Laurie Island, as they appear 

 from Scotia Bay, is given in the Annals of the Argentine Meteorological Office, vol. xvn, part 2, pp. 

 163-9. It is based on continuous daily observations (on icebergs as well as pack-ice) for the period 

 1903-10. The ice records presented here date from the first sighting of the group down to the present 

 day. They are concerned only with pack-ice and in the majority of instances^ only with that 



'■ Brown, R. N. Rudmose, 1923, A Naturalist at the Poles, p. 153 (London). 



^ In a few instances winter seasons have been considered, notably those that were exceptionally mild or 

 severe. 



