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XXXI. — Shackleton Antarctic Expedition, 1914-1917: The Natural History of 
Pack-Ice as observed in the Weddell Sea. By J. M. Wordie, M.A., F.G-.S. 
Communicated by Professor J. W. Gregory, F.R.S. (With Nine Text-Figures 
and Four Plates.) 
(MS. received December 6, 1920. Read February 7, 1921. Issued separately June 21, 1921.) 
CONTENTS. 
I. Introduction . 
II. Early Stages . 
III. The Ice in Motion . 
PAGE 
795 
800 
804 
IV. Changes in the Ice 
V. Decay . 
VI. Bibliography 
PAGE 
817 
825 
82 
I. — Introduction. 
The opportunities for observation were afforded by the voyage and subsequent drift 
of the S.Y. Endurance. During December 1914 and January 1915 for a period of 
six weeks she successfully bored her way through pack-ice of every description — 
drift-ice, open-pack, and very frequently even close-pack. Continually fighting, she 
penetrated from 59° to 72° S. lat., and finally reached the land water off Coats Land on 
the latter parallel. As the crow flies, therefore, she was navigated through ice for 
nearly 800 geographical miles On this voyage ; her actual course among the ice-fields 
and floes was computed to exceed 2000 miles, an achievement without parallel in the 
Antarctic. The principle adopted was to keep to the east, where presumably there is 
less pack than in the west ; if the Endurance experience is a normal one, however, 
the meridian of 20° W. long., which was followed, is certainly not far enough east. 
The exploration of Coats Land and the discovery of Caird Coast followed, until 
the ship was finally beset on January 19, 1915. From that date until October 1915 
she drifted northwards and westwards round the Weddell Sea at an average rate of 
four sea-miles per day, till finally crushed and abandoned on October 27. There- 
after the crew tried to sledge to land ; or, camped on the ice, drifted from the position 
where the ship was wrecked (69° S. lat.) through a further seven degrees of latitude. 
So passed a second summer in the ice ; and it was not till April 1916 that boats could 
be launched and escape effected, through the fringe of the pack, to Elephant Island. 
These seventeen months of close association in some form or other with pack-ice 
have led to an opportunity of studying its origin and decay, and some of the laws 
governing its behaviour, which has never before been afforded to a British expedition 
in the Antarctic. The conclusions thus obtained, particularly as regards the westerly 
drift, will, it is hoped, be of use to all future Antarctic navigators. 
From comparative study it appears as if the sea-ice cycle round the North Pole 
is much the same as in the South — spread, however, over a longer period and 
TRANS. ROY. SOC. EDIN., VOL. LII, PART IV (NO. 31). 124 
