slope which they thought might be descended by sliding or "glissading."
It was the first time that Emma had seen such work, and she felt much
inclined to try it, but was dissuaded by Antoine, who led her round by
an easier way. At the foot of the slope they came to a couloir, or
sloping gorge, so steep that snow could not lie on it. Its surface was,
therefore, hard ice. Although passable, Antoine deemed it prudent not
to cross, the more so that he observed some ominous obelisks of ice
impending at the top of the slope.

"Why not cross and let Emma see how we manage by cutting steps in the
ice?" said Lewis.

He received a conclusive though unexpected answer from one of the
obelisks above-mentioned, which fell at the moment, broke into
fragments, and swept the couloir from top to bottom with incredible
violence.

It is wonderful what a deal of experience is required to make foolish
people wise! Winthin the next ten minutes this warning was forgotten,
and Lewis led his cousin into a danger which almost cost the lives of
three of the party.

CHAPTER TWENTY.

RECORDS A SERIOUS EVENT.

Our ramblers had now reached a place where a great expanse of rock
surface was exposed, and the temptation to dilate on the action of
glaciers proved too strong for the Professor. He therefore led those
who were willing to follow to a suitable spot and pointed out the
striations, flutings, and polishings of the granite, which showed that
in former ages the glacier had passed there, although at that time it
was far below in the valley. The polishings, he said, were caused by
the ice slowly grinding over the surface of the rock, and the flutings
and groovings were caused, not by the ice itself, but by stones which
were embedded in its under surface, and which cut the solid granite as
if with chisels.

Meanwhile, Lewis and Emma, having taken the opportunity to search for
plants, had wandered on a little in advance, and had come to another
steep slope, which was, however, covered with snow at its upper part.
Below, where it became steeper, there was no snow, only pure ice, which
extended downwards to an immense distance, broken only here and there by
a few rocks that cropped through its surface. It terminated in a rocky
gorge, which was strewn thickly with _debris_ from above.

"Let us cross this," said Emma, with a look of glee, for she possessed
an adventurous spirit.

"We'd better not," answered Lewis. "The slope is ver