368 Slide from Mount Pilatus to the Lake of Lucerne. 



that has been observed in North America and probably one 

 of the most interesting in the world. A specimen now lies 

 before us more than six inches square, on which are depos- 

 ited between three and four hundred distinct cubes and par- 

 allelopipeds some of which are an inch in diameter, and 

 others so minute as to be almost microscopic; they are of a 

 deep violet and purple colour, and the whole group (except 

 that it has not quite the freshness of specimens which have 

 been recently taken from the cavities of mines) is scarcely 

 inferior to the finest pieces of Derbyshire and France. 



II. FOREIGN LITERARURE AND SCIENCE. 



1. Slide from Mount Pilatus to the Lake of Lucerne.^ 

 Communicated by Professor Griscom. 



A slide was erected in 181 2, by Mr. Rupp, for the purpose 

 of bringing down to the lake of Lucerne the fine pine trees 

 which grow upon Mount Pilatus. The wood was purchas- 

 ed by a company for 3,000Z and 9,000/ were expended in 

 forming the slide. The length of the slide is about 44,000 

 English feet, or about 8j miles, and the difference of level of 

 its two extremities is about 2,600 feet. 



It is a wooden trough about five feet broad and four deep, 

 the bottom of which consists of three trees, the middle one 

 being a little hollowed, and small rills of water are conduc- 

 ted into it to diminish friction. 



The declivity at its commencement is about 22i°, and it 

 was calculated by Professor Playfair that a heavy body, not 

 retarded by friction, would describe the whole length of the 

 trough in 66". 



The large pines with their branches and bows cut off, 

 are placed in the slide, and descending by their own gravity 

 they acquire such an impetus by their descent through 

 the first part of the slide, that they perform their journey of 



* Although these facts have been already published in our newspapers we 

 are willing to present them in a more permanent form. Indeed it often 

 happens that articles of scientific and literary intelligence go the round of 

 our principal newspapers, before it is possible that they should appear in 

 our more permanent journals. When the articles are interesting and im- 

 portant we shall hot think this a sufficient reason for omitting to insert 

 them, — Ed. 



