DISCOVERY 



265 



Why Pack-ice Drifts 



Only one other aspect of the drift can be considered 

 here, that of its motive power. This at first sight 

 seems to be simply the wind. When the wind blew 

 the ice moved approximately before it ; if it was 

 calm, the ice was nearly always stationary. The most 

 rapid drift was a distance of eighty-four miles in six 

 days, during a strong southerly gale, while for a whole 

 month immediately preceding this gale, during which 



to about lat. 65°, when the Dciilschland took a sudden 

 turn to the east. The average rate of drift of the 

 Deutschland was greater than that of the Endurance, 

 the latter being more to the west, and presumably 

 closer to land. It is difficult to escape the conclusion 

 that the unknown coast of the Weddell Sea must run 

 nearly parallel to the drift course of these two ships, 

 and the probability of any sea passage from the Weddell 

 Sea out to the Pacific south-west of Graham Land 

 seems small. If such a passage once existed, it is 



■'^P-, 



Falkland Is. 



Tmck of Endurance before being beset . 



Drift .. .. after .. .. 



.. camp-floes 



-. Deutschland 



Cape Horn 



South Georgia V\_ 



\ 



\ 



\ 



S. Orkney Is. 



Elephant I ^^ g,,- Ql>'*l. 



-« ^^A' Boats launched 



:tf-';<»l.„ 



\ 



crfV — , 



Pack -ice entered ■•- , 

 Dec. 1914 . * \ 



\ 



15 V. le. 



^Jchnuil/e I. 



A 



i. ^Deutschland 

 '1 Free 



Ji ■ ; crushed 



* 27. X 15 *^ ■■' 



Scale of Miles 



200 400 



Coats 

 Land 



Fig. 3.— M\P of THE.WKDDELI, SFA ILLUSTRATING THE DRIFTS OF THE ENDURANCE AND THE DEUTSCHLAXD. 



the winds had been light and variable, hardly a 

 mile had been made to the north. The wind is 

 doubtless the most important cause of the drift, but 

 a more complete examination of the observations than 

 has hitherto been possible will almost certainly bring 

 to light an outstanding effect due to current. The 

 direction of the drift was always a little to the left 

 of the direction of the wind. This is due to the rota- 

 tion of the earth, and a similar deviation to the right 

 of the wind direction was noticed by Nansen during 

 the drift of the Fraiii across the North Polar Basin. 

 The drifts of both the Endurance and the Deutschland 

 in the Weddell Sea show strangely parallel courses up 



probably now filled up with shelf-ice similar to that of 

 the great Ross Barrier. 



The various problems raised by the drift of the 

 Endurance which have been touched on above have 

 been considered very fully by Mr. J. M. Wordie, 

 geologist to the expedition, to whose work reference 

 should be made by those interested in the subject. 



REFERENCES FOR FURTHER READING 

 South, by Sir Ernest Shackleton. (Heinemann.) 

 The Natural History of Pack-ice as obserred in tlie Weddell 



Sea, by J.'M. Wordie. [Trans. Roy. Soc. Edinburgh, vol. lii. 



part iv, p. 795.) 

 Zum sechsten Erdteil , by Filchner. 



