110 Account of the celebrated Slide of Alpnach. 
It deserves to be noticed, that neither the thermometer, which 
was encircled with polished brass, nor the lead, could be per- 
ceived at greater depths than from to 4j fathoms, though the 
water had the most perfect transparency. 
Along with the map, I have given four sections of the Lake, 
in which the scale of depths is the same as that of the horizontal 
distances. 
Art. XIX . — -Account of the celebrated Slide of Alpnach, con- '■ 
structed on Mount Pilatus by M. Rupp, Engineer Com- 
municated by Professor Pictet. 
In our first Number, p. 193, we had occasion to give a brief 
notice of the celebrated slide of Alpnach, constructed upon 
Mount Pilatus, in the Canton of Underwald, by Mr John 
Rupp of Reutingen in Suabia ; and we have particular pleasure 
in being able to recall the attention of our readers to a work no 
less interesting, from its stupendous magnitude, than from the 
talents and perseverance which have been exhibited in its con- 
struction. 
For many centuries, the rugged flanks and the deep gorges 
of Mount Pilatus were covered with impenetrable forests. Lofty 
precipices encircled them on all sides. Even the daring hunters 
were scarcely able to reach them, and the inhabitants of the 
valley had never conceived the idea of disturbing them with 
the axe. These immense forests were therefore permitted to 
grow and to perish, without being of the least utility to man, 
till a foreigner, conducted into their wild recesses in the pursuit 
of the chamois, was struck with wonder at the sight, and direct- 
ed the attention of several Swiss gentlemen to the extent and 
superiority of the timber. The most intelligent and skilful in- 
dividuals, however, considered it quite impracticable to avail 
themselves of such inaccessible stores. It was not till November 
1816 that M. Rupp and three Swiss gentlemen, entertaining 
more sanguine hopes, drew up a plan of a slide, founded on 
trigonometrical measurements. Having purchased a certain ex- 
tent of the forests from the commune of Alpnach for 6000 
* This article is drawn up from a manuscript translation of a paper in Gil- 
bert’s Annahn^ 1819, Cahier 5, made for the BUbliotheque C7^neuer«eZ^e.— Ed. 
3 
