io Arctic and Antarctic Exploration [part i 
of feet. The ice walls at the heads of the discharging 
glaciers are driven onwards by the force of gravity, the 
pressure of the superincumbent mass behind them being 
enormous. In some .cases the rate of movement is as 
much as 28 yards in a day. 
A discharging glacier, on reaching the sea, has a 
thickness of at least a thousand feet. It continues to 
slide along the bottom until it reaches a point where 
the depth of the water has sufficient buoyant force to 
lift it. Still it continues its course. The action of the 
tides gives rise to fissures in the enormous mass, and at 
length the foremost part is broken off, and drifts away 
as an iceberg. The icebergs are discharged from the 
fjords in vast numbers, and are eventually carried by the 
current of Baffin's Bay and Davis Strait into the Atlantic. 
The icebergs are alike the grandest and the most 
beautiful features of the Arctic seas. Only one-seventh of 
their bulk appears above water, yet they may be hundreds 
of yards in circumference, and their peaks reach a height 
of 300 ft. A grander sight can scarcely be conceived 
than new-born icebergs drifting out from the fjord of 
their birthplace. When the icebergs drift well out into 
the open sea the weathering and consequent reduction in 
size begins. They eventually lose their equilibrium and 
capsize. The part that has been long under water 
becomes the upper part, and it is now that the bergs 
assume their most fantastic shapes. Very often a large 
piece breaks off from the parent berg, and falls into the 
sea, churning it up into creamy waves. This is called 
calving. 
The colour of an iceberg is opaque white. Scattered 
through the mass, and sometimes visible on the surface, 
are strata of deep blue ice, varying in width from one to 
several feet. They have an exquisitely lovely effect, 
contrasting with the deep white of the rest of the berg. 
These blue stripes may be formed by a filling up of the 
fissures in the inland ice with water. Such refrigeration 
of the water in the fissures may be an important agent 
in setting these great mountains of ice in motion. 
Sometimes there is a passage right through an iceberg. 
But it is when a line of icebergs is refracted on the 
horizon that the polar scenery is converted into a 
