192 G. H. HALLIGAN. 



split into three portions, the first being bent round and 

 flows eastward as a warm surface current; the second is 

 also carried eastwards, and mixing with the colder stream, 

 helps to account for the rise of temperature — from 41° Fah. 

 to 50° Fall., according to season — which is observed between 

 latitudes 50° and 60° south; the third is that part which, 

 having become cooler and therefore heavier, sinks below 

 the cold surface water, and taking a south-easterly course, 

 flows as a comparatively warm under current, into the 

 Antarctic Ocean. 



This warm water, in conjunction with that of the 

 Brazilian current in the South Atlantic, and the Aghulhas 

 or Cape Current of the Indian Ocean may cause the under- 

 mining of the enormous ice-masses which form the "Ice 

 barrier," detaching from them the numerous floating ice- 

 bergs which strew the face of the Southern Ocean down to 

 50° and 40° South latitudes. 



The melting of these ice masses produces a quantity of 

 water, which, being fresher, is of less specific gravity than 

 the salt water of the surrounding sea, and therefore floats 

 upon it, but as the fresher water from the icebergs mixes 

 with this salt water, the mixture being of lower tempera- 

 ture is rendered heavier and sinks, and hence the supply of 

 cold water which, to a depth of several thousand fathoms, 

 fills the basins of the Atlantic, Pacific, and Indian Oceans. 1 



The portion which is bent round and flows eastward con- 

 tinues its journey thus till it strikes the west coast of New 

 Zealand, when it is again deflected to the northward along 

 that coast as far north as Oape Maria Van Diemen, where 

 it turns to the west and is lost in the waters of the Tasman 

 Sea. 



Between Great Sandy Oape and Jervis Bay, the Eastern 

 Australian Current, for which the name Tasman Current is 



1 Thalassa by J. J. Wild, London, Marcus Ward & Co., 1877. 



