62 British Antarctic Expedition. 
heavy screw caused by swell, the life of the vessel 
may entirely depend upon whether the vessel is worked 
away from the direction from which the swell comes, 
and into the quiet pack or not. Those who have not 
experienced the dangers of swell in the ice, and have 
not had to determine the direction whence it comes, 
would not realise the difficulty, and it takes an ex- 
“THE ICE SLACKENED SOMEWHAT.” 
perienced man to ascertain it under certain conditions. 
The best way is to lie down upon the ice and listen to 
the roar of the crushing ice. The roar of the grinding 
ice masses travels in the air in waves like the swell 
itself. Only by lying down upon the ice can you 
ascertain whence this noise comes, and determine 
the direction in which you have to work the vessel 
into safety. 
