The Scientific Advantages of an Antarctic Expedition. 429 



Deposits of the Antarctic Ocean. 



The deposits which have been obtained close to the Antarctic con- 

 tinent consist of bine mud, containing glanconite, made up for the 

 most part of detrital matters brought down from the land, but con- 

 taining a considerable admixture of the remains of pelagic and other 

 organisms. Further to the north there is a very pure diatom ooze, 

 containing a considerable quantity of detrital matter from icebergs, 

 and a few pelagic foraminifera. This deposit appears to form a zor.e 

 right round the earth in these latitudes. Still further to the north 

 the deposits pass in deep water, either into a Globigerina ooze, or 

 into a red clay with manganese nodules, sharks' teeth, ear-bones of 

 whales, and the other materials characteristic of that deep-sea 

 deposit. Since these views, however, as to the distribution of cleep-sea 

 deposits throughout these high southern latitudes, are founded upon 

 relatively few samples, it cannot be doubted that further samples 

 from different depths in the unexplored regions would yield most 

 interesting information. 



Temperature of the Antarctic Ocean. 



The mean daily temperature of the surface waters of the Antarctic, 

 as recorded by Ross, to the south of latitude 63° S. in the summer 

 months, varies from 27"3° to 33'6°, and the mean of all his obser- 

 vations is 29'85°. As already stated, his mean for the air during the 

 same period is somewhat lower, being 28* 74°. In fact, all observa- 

 tions seem to show that the surface water is warmer than the air 

 during the summer months. 



The " Challenger " observations of temperature beneath the 

 surface indicate the presence of a stratum of colder water wedged 

 between warmer water at the surface, and warm water at the bottom. 

 This wedge-shaped stratum of cold water extends through about 12° 

 of latitude, the thin end terminating about latitude 53° S., its tem- 

 perature varying from 28° at the southern thick end to 32"5° at the 

 northern thin end, while the temperature of the overlying water , 

 ranges from 29° in the south to 38° in the north, and that of the 

 underlying water from 32° to 35°. This must be regarded as the 

 distribution of temperature only during the summer, for it is im- 

 probable that during the winter months there is a warmer surface, 

 layer. 



In the greater depths of the Antarctic, as far south as the 

 Antarctic circle, the temperature of the water varies between 32° and 

 35° F., and is not, therefore, very different from the temperature of 

 the deepest bottom water of the tropical regions of the ocean. The 

 presence of this relatively warm water in the deeper parts of the 



