surface of the glacier. This was simply to be used as a belaying-pin,
to which the ends of the pulley-ropes could be fastened at a moment's
notice.

The next operation was the reeving of the ropes over the wheels of the
pulley. This was the work of but a few minutes, as the ropes had
already been carefully twisted, and had been made of just the thickness
to fit the grooves of the wheels.

The ropes--or cables, as the boys called them--were now attached at one
end to the great pole which was to form the bridge. One to its end, and
the other to its middle, exactly around the place where it was joined.

The greatest pains was taken in adjusting these knots, particularly the
one in the middle; for the duty which this cable was called upon to
perform was, indeed, of a most important character.

It was to act as the main pier or support of the bridge--not only to
prevent the long pole from "swagging" downward, but in fact to keep it
from breaking altogether. But for Karl's ingenuity in devising this
support, a slender pole, such as that they had prepared, would never
have sustained the weight of one of them; and had they made it of
heavier scantling, they could not have thrown it across the chasm. The
centre support, therefore, was the chief object of their solicitude; and
this cable, as well as the pulley-wheel over which it passed, were made
much stronger than the other. The second rope was intended to hold up
the end of the pole, so that, on approaching the opposite side of the
chasm, it could be kept high enough to be raised above the ice.

The ropes being now completely rigged, each man took his place.
Ossaroo, who was the strongest of the party, was to push the bridge
forward; while Karl and Caspar attended to the pulley and the ropes.
Rollers had already been laid under the poles; for, although but six
inches in diameter, its great length rendered it no easy matter to slide
it forward, even with the advantage of the slippery surface of frozen
snow.

The word was given by Karl, and the pole commenced moving. Soon its end
passed over the brink of the chasm, close by the edge of the black rock.
Slowly and gradually it moved forward, and not one of them uttered a
word. They were all too much absorbed in attending to their various
duties to speak a sentence.

Slowly and gradually it moved onward, creeping along the cliff, like
some huge monster, and protruding its muzzled snout far over the deep
chasm.