Each glacier in Greenland, so far as any estimate has been made, is the
parent each year of from ten to one hundred icebergs. When these bergs
have plunged into the Arctic Sea, they are picked up by the Arctic
current and begin their journey to the North Atlantic. But there are
thousands of them afloat; they crowd and rub against each other and
frequently they break into smaller masses.

Many go aground in the Arctic basin; others get to the shores of
Labrador, where from one end to the other they continually ground and
float. Some disappear there, while others get safely past and reach the
Grand Banks.

According to Ensign Rodman, the ice of bergs, although very hard, is at
the same time extremely brittle. A blow of an axe will at times split
them, and the report of a gun, by concussion, will accomplish the same
end.

They are more apt to break up in warm weather than in cold, and whalers
and sealers note this before landing on them when an anchor is to be
planted or fresh water to be obtained.

On the coast of Labrador, in July and August, when it is packed with
bergs, the noise of rupture is often deafening, and those experienced in
ice give them a wide berth.

When they are frozen the temperature is very low, so that when their
surface is exposed to a thawing temperature the tension of the exterior
and interior is very different, making them not unlike a Prince Rupert's
drop.