498 THE ANTARCTIC MANUAL. 
and recrossed the antarctic circle. This, with the exception of the 
Belgica, is the longest period a ship has ever been involved in that pack, 
Our long imprisonment was due to having entered it so far west, in 
long. 158° 53' E., where it is very dense and heavy. 
On first entering, ice was visible to the horizon in the south and 
west, whilst in the east and south-east there was open water. Our 
experiences, and those of other expeditions, tend to prove that the ice- 
pack on the Australian side of the antarctic circle is not nearly so dense 
in an easterly as it is in a westerly direction. Ships that have entered 
the pack in about 170° E. long. have penetrated it in a few days, 
whilst those entering it between 150° and 165° Ei. have taken more 
than a month. There are numerous instances in the history of antarctic 
navigation which go to prove this. A strong cold surface current 
appears to set out from Ross sea in a north-westerly direction, driving 
the ice up northwards, between Kerguelen island and Australia, At 
Capo Adare huge bergs were often observed, during perfectly calm 
weather, travelling at about 4 knots an hour towards the north-west. 
The prevailing south-east winds are also a factor in driving the ice in 
that direction. 
The sea-ice, which constitutes the bulk of the pack, is first formed 
by the freezing of the sea in the winter along the shores of the antarctic 
lands. ‘This freezes to an average depth of from 4 to 5 feet, and 
extends out into the ocean for perhaps 50 miles, until the formation of 
an uninterrupted sheet of ice is prevented by its perpetual violent 
agitation. This ice begins to break up early in November, and move 
northwards, and by the middle of January the coasts are almost free. 
As this body of sea-ice moves towards the north, it is frequently driven 
back by northerly winds. Thus, in consequence of the circumstance 
that land lies to the south, which excludes the possibility of more sea- 
ice following in support, an open sea, comparatively free from ice, is met 
with in the antarctic regions almost regularly when the principal zone 
of pack-ice has been pierced. Serious danger from ice-pressure in the 
open pack is comparatively slight. Once, on January 24, a rather 
severe pressure set in during a gale from the E.S.E., when the Southern 
Cross was fast wedged in the ice. On the port side the blocks piled up 
to a height of nearly 15 feet, and on that side the ship was lifted + feet 
out of the water, but at no time were we anxious for her safety. The 
pack, very susceptible to a gale, drives before it, and so there is really 
no danger, for there is no resisting force. But woe betide a ship that 
ventures to winter near the coast, unless it be a well-sheltered inlet, for 
when a pressure sets in there, it piles the huge blocks of ice up on the 
shore to from 20 to 60 feet, and a ship would surely be crushed, no 
matter how strongly she may be built. A real source of danger, how- 
ever, is a gale or a very heavy swell on the edge of the pack, when 
huge masses of ice crash into the sides of the ship with terrific force, 
