MAGNETIC TELEGRAPH. 35 



is like lightning, and readily leaps and escapes 

 from the surfaces on which it is confined. The 

 galvanic current also readily decomposes acid- 

 ulated water, and many other substances, and 

 this capacity was soon applied to the purposes of 

 telegraphy. Scemering, in 1807, invented a tele- 

 graph on this plan, and continued it for several 

 years in Munich, publishing accounts of it in sci- 

 entific journals, and exhibiting it to learned socie- 

 ties.* Others followed his lead, until finally it 

 came into commercial use in England in 1846 as a 

 rival to the electro-magnetic telegraph of later 

 invention ; but requiring its aid, as an alarm.f 



In 1820, Oersted discovered the capital fact that 

 a galvanic current, passing through a wire placed 

 horizontally above, and parallel to, an ordinary 

 compass needle, will cause that needle to sway on 

 its axis to the east or west, according to the direc- 

 tion of the current through the wire. At once 

 Ampere suggested the application of the new dis- 

 covery to the old telegraph, whereby galvanism 

 might be substituted for static electricity, and 

 the deflection of a magnetic needle for the diver- 

 gence of the pith balls of the electroscope. Baron 

 Schilling, a Eussian nobleman, inspired by the love 

 of science, accordingly took up this suggestion, 

 and constructed a galvanometer or needle tele- 



* See Appendix, Note I. 

 t See Appendix, Note K. 



