82 FOUNDERS OF OCEANOGRAPHY 



evidence in favour of it from the " Challenger " results, was 

 the theory of " Bipolarity," viz., that identical organisms 

 were found in Arctic and Antarctic seas and not in inter- 

 mediate waters, and that they represented the original marine 

 fauna which at some earlier period of the earth's history 

 inhabited all the oceans. This bipolarity hypothesis has 

 been vigorously controverted, and, like some other theories in 

 science which have had to be abandoned, was most useful 

 in its day as giving rise to much new investigation. A 

 good deal of evidence against Murray's views on bipolarity 

 has been accumulated as the result of recent Antarctic 

 expeditions. 



But whether all his views are accepted or not, they are all 

 very stimulating and useful, and have given rise to much 

 investigation and discussion in the history of oceanography. 

 His five great volumes are a notable monument to his 

 memory. They and the other " Challenger " reports which 

 he edited record collectively the greatest advance in the 

 knowledge of our planet since the great geographical dis- 

 coveries of the fifteenth and sixteenth centuries. 



I referred in the last chapter to the subsidiary expeditions 

 (1880-2) for the purpose of investigating the very remark- 

 able conditions of temperature and fauna in the Faroe Channel. 

 We saw how Carpenter and Wyville Thomson, during 

 the preliminary investigations in the " Lightning " and 

 " Porcupine," had found that the Faroe Channel was divided 

 into two regions — a " cold " and a " warm " area. The 

 temperature of the water to a depth of 200 fathoms is much 

 the same in the two areas ; but in the cold area to the N.E. 

 the temperature is about 34° F. at 250 fathoms, and about 

 30° at the bottom in 640 fathoms, while in the warm area, 

 which stretches S.W. from the line of demarcation, the tem- 

 perature is 47° F. at 250 fathoms, and 42° at the bottom 

 in 600 fathoms. A consideration of the " Challenger " 

 temperatures led to the conclusion that the cold and warm 

 areas of the Faroe Channel must be separated by a very con- 



