ICEBERGS 
451 
prime cause of the calving of bergs from the parent 
glacier is due to the melting action of the warm sea water. 
Bergs met with in the Antarctic can best be roughly 
divided into barrier or tabular bergs and glacier bergs. 
The tabular berg is recognised by its flat tabular form, 
whereas the glacier berg seldom has such a regular profile 
and often is formed of deep blue ice in contradistinction 
to the dazzling whiteness of the barrier berg. The 
tabular berg has a height up to 200 feet above sea and at 
times reaches the enormous length of 21 miles — truly a 
floating island. After partial melting it usually becomes 
slightly tilted to one side, or develops enormous caverns 
due to the action of the waves. In the final stages it 
may overturn or even disintegrate and after prolonged 
exposure to the elements is hardly distinguishable from 
the glacier berg. 
The general tendency of the currents in the Ross Sea 
is to carry these bergs northwards into the warmer water, 
so that in late summer the greatest accumulation of bergs 
occurs at a fairly low latitude. As a result also of their 
great heat capacity they are not associated at this time 
of the year with pack ice as they are in the early 
summer. 
That the number and distribution of these enormous 
reservoirs of cold has a real effect upon the climate of 
Australasia can hardly be doubted, and it is therefore 
evident that a close study and analysis of the data on 
this subject may well give results of the very greatest 
value. 
