THE HEART OF THE ANTARCTIC 



Lakes and Lake Ice. — ^We found it difficult during 

 the short period of our stay in the Antarctic to ascertain 

 to what thickness this ice formed during a single season. 

 The difficulty arose from the fact that in the summer of 

 1908-1909 the fresh water ice of these lakes did not 

 entirely thaw. 



Some of the lakes were slightly saline, and some of 

 these, such as Green Lake and Coast Lake, thawed com- 

 pletely during the summer and during the winter the ice 

 froze over them from top to bottom until, in the case of 

 Green Lake, in August 1908, only a very little sahne 

 water, a few inches in depth, remained unfrozen, below 

 a thickness of 5 ft. of ice. At the same time of year the 

 water of " Coast Lake," also somewhat saline, was frozen 

 solid, the lake being a little under 5 ft. deep. 



In the case of the fresh-water lake, known as Clear 

 Lake, it was noticed that during the summer the ice thawed 

 chiefly on the south side of the lake, where it was in 

 contact with the black rock, and where that rock was 

 specially warmed by the sun's rays. The sun being 

 highest when it is due north, has its greatest heating 

 effect on southern slopes. The ice towards the middle and 

 north side of the lake did not wholly thaw. The same 

 remark is true of the ice of the Blue Lake near our winter 

 quarters. 



In the case of the Blue Lake we found, as the result 

 of the shafts sunk, that in the south-west division of this 

 lake the ice was at least 15 ft. in thickness, while in 

 the north-western division Brocklehurst sunk a shaft 

 to 21 ft., but in his case a little water was found be- 

 neath the ice, whereas in the first case the ice was solid 

 down to the bed rock. We are of opinion that this Blue 

 Lake ice had not been thawed for probably at least three 

 seasons. 



As many of these small lakes were encircled by steep 



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