The first thought that will strike you, will be how that piece of timber is to be placed across that yawning chasm. It is quite long enough to reach across—for they calculated that before making it—and there are several feet to lap over at each end; but how on earth is it to be extended across? If any one of the party was upon the opposite side, and had a rope attached to the end of the pole, then it would be easy enough to manage it. But as there could be nothing of this kind, how did they intend acting? It is evident they could not push it across before them; the end of such a long pole would naturally sink below the horizontal line before reaching the opposite side; and how was it to be raised up? In fact, as soon as they should push it a little more than half its length outward, its own weight would overbalance their united strength, and it would be likely to escape from their hands and drop to the bottom of the cleft—whence, of course, they could not recover it. This would be a sad result, after the trouble they had had in constructing that well-balanced piece of timber.
Ah! they were not such simpletons as to have worked a whole month without first having settled all these matters. Karl was too good an engineer to have gone on thus far, without a proper design of how his bridge was to be thrown across. If you look at the objects lying around, you will perceive the evidence of that design. You will understand how the difficulty is to be got over.
You will see there a ladder nearly fifty feet in length—several days were expended in the making of this; you will see a strong pulley, with block-wheels and shears—this cost no little time in the construction; and you will see several coils of stout rawhide rope. No wonder a month was expended in the preparation of the bridge!
And now to throw it across the chasm! For that purpose they were upon the ground, and all their apparatus with them. Without farther delay the work commenced.
The ladder was placed against the cliff, with its lower end resting upon the glacier, and as close to the edge of the crevasse as was reckoned safe.
We have said that the ladder was fifty feet in length; and consequently it reached to a point on the face of the cliff nearly fifty feet above the surface of the glacier. At this height there chanced to be a slight flaw in the rock—a sort of seam in the granite—where a hole could easily be pierced with an iron instrument.
To make this hole a foot or more in depth was the work of an hour. It was done by means of the hatchet, and the iron point of Ossaroo’s boar-spear.
A strong wooden stake was next inserted into this hole, fitting it as nearly as possible; but, in order to make it perfectly tight and firm, hard wooden wedges were hammered in all around it.
When driven home, the end of this stake protruded a foot or more from the wall of the cliff; and, by means of notches cut in the wood, and rawhide thongs, the pulley was securely rigged on to it.
The pulley had been made with two wheels; each of them with axles strong enough to bear the weight of several hundreds. Both had been well tested before this time.