339.  Slide of Alpnach.  Amongst the forests which flank many of the lofty mountains of Switzerland, some of the finest timber is found in positions almost inaccessible.  The expense of roads, even if it were possible to make them in such situations, would prevent the inhabitants from deriving any advantages from these almost inexhaustible supplies.  Placed by nature at a considerable elevation above the spot at which they can be made use of, they are precisely in fit circumstances for the application of machinery to their removal; and the inhabitants avail themselves of the force of gravity to relieve them from some portion of this labour.  The inclined planes which they have established in various forests, by which the timber has been sent down to the water courses, have excited the admiration of every traveller; and in addition to the merit of simplicity, the construction these slides requires scarcely anything beyond the material which grows upon the spot.

Of all these specimens of carpentry, the Slide of Alpnach was the most considerable, from its great length, and from the almost inaccessible position from which it descended.  The following account of it is taken from Gilbert’s Annalen, 1819, which is translated in the second volume of Brewster’s Journal: 

For many centuries, the rugged flanks and the deep gorges of Mount Pilatus were covered with impenetrable forests; which were permitted to grow and to perish, without being of the least utility to man, till a foreigner, who had been conducted into their wild recesses in the pursuit of the chamois, directed the attention of several Swiss gentlemen to the extent and superiority of the timber.  The most skilful individuals, however, considered it quite impracticable to avail themselves of such inaccessible stores.  It was not till the end of 1816, that M. Rupp, and three Swiss gentlemen, entertaining more sanguine hopes, purchased a certain extent of the forests, and began the construction of the slide, which was completed in the spring of 1818.

The Slide of Alpnach is formed entirely of about 25,000 large pine trees, deprived of their bark, and united together in a very ingenious manner, without the aid of iron.  It occupied about 160 workmen during eighteen months, and cost nearly 100,000 francs, or L4,250.  It is about three leagues, or 44,000 English feet long, and terminates in the Lake of Lucerne.  It has the form of a trough, about six feet broad, and from three to six feet deep.  Its bottom is formed of three trees, the middle one of which has a groove cut out in the direction of its length, for receiving small rills of water, which are conducted into it from various places, for the purpose of diminishing the friction.  The whole of the slide is sustained by about 2,000 supports; and in many places it is attached, in a very ingenious manner, to the rugged precipices of granite.

The direction of the slide is sometimes straight, and sometimes zig-zag, with an inclination of from 10 degrees to 18 degrees.  It is often carried along the sides of hills and the flanks of precipitous rocks, and sometimes passes over their summits.  Occasionally it goes under ground, and at other times it is conducted over the deep gorges by scaffoldings 120 feet in height.