SLIDE is the name given to an inclined plane for facilitating the descent of heavy bodies by the force of gravity. In general, they have been objects of no great importance; but one was lately erected at Alp nach, in Switzerland, which has excited great interest throughout Europe.
For many ages, the craggy sides and the deep ra vines of Pilatus, a lofty mountain near Lucerne, were thickly clothed with vast and impenetrable forests of spruce fir, of the largest size, and the finest quality, surrounded on every side by the most terrific preci pices, inaccessible to all but a few daring hunters, who, at the risk of their lives, scaled these precipit ous rocks and crags, in pursuit of the chamois. It was from these bold adventurers that the first intelli gence was derived concerning the size of the trees, and the extent of the forests, until a foreigner, who had visited their sequestered glades and gloomy re cesses, in pursuit of the chamois, was struck with amazement at the sight, and pointed out to the atten tion of several Swiss gentlemen, the vast extent, and superior quality of the timber. The project of mak ing use of these rich natural stores, was however re jected as chimerical by persons, whose experience and skill made them competent to judge; and it was consequently abandoned. This attempt having failed, these immense and valuable forests would, in all pro bability, have been suffered to flourish and decay, without ever being applied to the use of man, if it had not been for the enterprising genius, and the un wearied exertion of M. Rupp, a native of Wirtem berg, who, owing to some political changes which had taken place in his own country. had settled near the Lake of Lucerne. ' His curiosity being strongly excited by the accounts he had heard of the forest, he was induced to visit it. He was so much struck by its wonderful appearance, that he entertained the idea of being able to convey the trees into the Lake of Lucerne, solely by their own gravity. During his long residence in Switzerland, his character and ta lents were so much appreciated, that, with the assis tance of three Swiss gentlemen, he soon formed a company from among the proprietors, with a joint stock, to enable them to purchase the forest, and to construct a road or Slide, down which it was intend ed the trees should be precipitated in the Lake of Lucerne, an arm of which washed the bottom of the mountain, from which they could be easily conveyed by the Rhine to any part of the German Ocean. This stupendous undertaking was finished in 1816.
The Slide of Alpnach was composed of between 25,000 and 30,000 large pine trees, squared by the axe, and formed into a sort of trough, about six feet broad, and from three to six feet deep. In the bot tom of the trough there was a groove for the recep tion of a small stream of water, let in over the side of the trough every now and then, in order to keep the whole structure moist, and thereby to diminish the excessive friction, occasioned by the rapidity of the descent of the tree.
The slide was sustained by cross timbers, and these cross timbers were themselves supported by uprights fixed into the ground. It was sometimes carried along the faces of the most rocky eminences, sometimes it went under ground, and again it crossed the deepest ravines, where it was supported by scaffoldings 120 feet high. The skill and ingenuity which were dis played, and the difficulties which were surmounted, in this vast undertaking, gained a just tribute of ad miration to the enterprising individual who projected and carried it. through. Before the work could even 1?e begun, it was necessary to cut down many thousand trees, to obtain a passage for the labourers through the impassable thickets. And M. Rupp was himself frequently obliged to descend the steepest precipices, suspended by ropes, at the imminent hazard of his life. And though he was attacked by a violent lever, yet his ardour was so great that he had himself con veyed every day, on a barrow, to the mountain, in or der to superintend the operations of his workmen.
The expense attending this undertaking was, accord ing to one account, or t 10,000; but according to another only 4,250. Before the trees were launched into the slide some previous preparation was necessary, which consisted in lopping off the branches, and stripping them of the bark, that they might de scend with the greater case. Every thing. being pre pared, the tree was introduced into the trough, with the root foremost; and it descended with such velocity as to reach the lake in 6 minutes, a distance of' about three leagues or nine miles; but the largest trees per formed the same distance in about three minutes. In order to prevent the accidents, which might take place, if' the tree was let off before every thing was ready at the lower end, a regular telegraphic commu nication was established between the two extremities of the slide; and workmen were posted at regular distances, of about a mile from each other, and so ar ranged that every station should be visible from the ones both above and below idc- When the tree was launched the workmen at the upper end hoisted their telegraph, (which consisted of a board, turning at its middle on a horizontal axle. The board when placed upright was visible from the two stations above and below it, but when it was turned horizontally it was not perceptible from either,) the same signal was re all the rest in succession, so that the work men at the lower end of the trough received intimation of the approach of the tree almost instantaneously. In a few minutes the tree came thundering past the men, and plunged into the lake. The lowest board was then turned down, which was followed immedi ately by all the rest, and thus the workmen at the top were informed of' the sale descent of the tree. The same operation was repeated during the rest of the clay; and it was so arranged that a tree should descend every five or siZminutes. When the progress of tire tree was impeded by any obstacle, or when it started out of the trough, the board was only half depressed; and as the workmen knew by this signal that some thing was wrong, those who occupied the stations above and below the place where the tree had stuck, came and assisted in removing the obstruction, NN h]ch was. generally occasioned by the springing of a biWm in the trough.
In order to prove the enormous force which the trees acquired by the rapidity of their descent, Rupp caused some of them to spring from the trough. The result was, that they penetrated the earth by their thickest ends to the depth of I 8 and sometimes 24 feet. And one of them having accidentally come in contact with another, cleft it from top to bottom with the violence and rapidity of lightning. In order that none of the wood might he lost, M. Rupp constructed several extensive manufactories in differ ent parts of the forest, for the purpose of reducing it to charcoal. He also built magazines for preserving it when made. The trees, after having reached the lake, were made up into rafts, and floated down the Reuss by the Aar, into the Rhine. By this rapid con veyance, they generally arrived at Basle a few days after they had left Lucerne. At Basle they passed out of the hands of the company. They were still floated clown the Rhine in rafts to Holland; and thus performed a journey of about 4000 miles in less than a month from the time they left Pilau's, until they ar rives: at the German Ocean.
We are sorry to acid that this stupendous work of art is now totally destroyed; and that almost every trace of it is obliterated on Mount Pilatus. The great demand which formerly existed for the timber having entirely ceased, owing to political causes, the cutting and transporting of the timber was necessarily dis continued, and the slide was suffered to go to ruin. See Playfair's rks, vol. i. Appendix, No. 2, p. 89.