196 Miscellanies. 



no less remarkable as a writer, and in his social capacity, by the brill- 

 iancy and keenness of his remarks, by a memory which never failed, 

 by long experience of men and things, favored by his social posi- 

 tions and his numerous journeys. He encouraged, by every means 

 in his power, a zeal for astronomy, wherever he found it; he formed 

 several distinguished astronomers, and greatly contributed by his 

 works and influence to that development which astronomy has un- 

 dergone in Germany. Baron de Zach had, jn various parts of Swit- 

 zerland, as in the rest of Europe, devoted friends, who are deeply 

 sensible of his loss. May this feeble homage of gratitude and re- 

 gret, bestowed upon his memory, alleviate in some measure their 

 reasonable sorrow. — A. Gautier. Bib. Univ. Aout, 1832. 



CHEMISTRY AND MECHANICAL SCIENCE. 



I 



1. Electro-Magnetism.* — M. Hachette announced to the French 

 Academy of Sciences, on the 3d of September, that Pixii had con- 

 structed an electro-magnetic apparatus, which produces sparks at a 

 distance. It was known, that if an unmagnetized horse shoe, around 

 which is wound a connecting wire covered with silk thread, is made 

 to approach a horse shoe magnet, with their extremities opposite to 

 each other, a spark is perceived at the moment of their separation ; 

 but that the experiment will not succeed, unless the contact is imme- 

 diate and the magnet very strong. With the new apparatus, a force 

 of five or six kilogrammes is sufficient to produce sparks at the dis- 

 tance of several millemetres. 



A horse shoe magnet is placed vertically, with the ends upwards. 

 Through the center of the curved part passes a vertical axis, on 

 which it may turn horizontally by means of a pinion and wheel on 

 which the motion is impressed. Above, and in a fixed position, is 

 an unmagnetized horse shoe, whose ends are adjacent to those of 

 the magnet without touching them. It is enveloped with a wire 



whose extremities rest in a capsule of mercury, one of them dipping 

 into it and the other just bordering upon the surface. When the 

 magnet is made to revolve, every time its poles pass under the ends 

 of the iron, so as to be in the same vertical plane with them, a spark 

 is manifest at the surface of the mercury, and if the motion be rapid 



* We preserve this notice of a discovery already announced in this No., because 

 it contains some additional particulars. — Ed. 



