alter.

"It's an island, though it's afloat. That is an iceberg," answered the
mate. "It's little less, I judge, than three miles in circumference,
and is several hundred feet in height."

The vast mass rose and fell in the water with a slow motion, while its
higher points seemed to reach to the sky, and often to bend towards each
other as if they were about to topple over. The waves furiously dashed
against its base, breaking into masses of foam; while ever and anon
thundering sounds, louder than any artillery, reached the ears of the
voyagers, as from the mighty berg, cracking in all directions, huge
pieces came tumbling down into the water. Above the thick fringe of
white foam appeared an indigo tint, which grew lighter and lighter, till
it shaded off from a dark-blue to the pile of pure snow which rested on
the summit.

Walter could not resist the temptation of bringing Alice to see the
strange and beautiful sight. Hurrying below, he wrapped her up in a
warm cloak, and, calling Nub to his assistance, they brought her on
deck.

"That is beautiful," she exclaimed; "but how dreadful it would be to run
against it in the dark!" she added, after a minute's silence.

"We hope to keep too bright a lookout for anything of that sort," said
the mate; "and, happily, at night we know when we are approaching an
iceberg by the peculiar coldness of the air and the white appearance
which it always presents even in the darkest nights. However, there can
be no doubt that many a stout ship has been cast away on such a berg as
that; or on what is more dangerous still, a floating mass of sheet-ice
just flush with the water."

The mate would not allow Alice to remain long on deck for fear of her
suffering from the cold, and Walter and Nub hurried her below. Walter
was soon again on deck. The ship was passing the iceberg, leaving it a
mile to leeward. As it drew over the quarter there was a cry from
forward of "Ice ahead!" The captain was immediately called.

"Hard up with the helm!" he shouted; and the ship passed a huge mass of
ice, such as the mate had before described, flush with the water. Had
the ship struck against it, her fate would have been sealed. The
sharpest eyes in the ship were kept on the lookout: one man on each bow,
and another in the bunt of the fore-yard; the third mate forward, and
one on each quarter. Two of the best hands were at the wheel; while the
captain and first mate were moving about with