S/X WILLIAM SIEMENS, F.R.S. 19 



electrical science, I mean the discovery of induction and of 

 nagneto-eleotrio currents by Faraday in 1881. 



(iauss and Weber rightly judged the superiority of magneto- 

 electric over voltaic currents for telegraphic purposes, and in 

 applying them they effectually established the first working elec- 

 tric telegraph in 1833, with the arrangements of which I be- 

 <MMK' practically acquainted some years later, when a student at 

 Goettingen. 



It consisted of a line wire and return current wire, the former 

 of which was carried upon high posts over the town of Goettingen, 

 extending from the Observatory to the tower of the Public 

 Library, and thence to the new magnetic observatory of "Weber, a 

 distance of little more than an English mile. The magneto- 

 electric current was produced by means of a coil containing 

 3,500 turns, which was situated upon a compound bar magnet, 

 weighing 75 Ibs., the coil being at liberty to slide freely to and 

 fro upon the bar. In sliding the coil rapidly from the centre 

 toward the south pole of the magnet and back again, a succession 

 of two opposite currents was produced, which, traversing the line 

 wire circuit, including coils of the receiving instrument, caused a 

 short jerk of the needle, say to the right and back again, whereas 

 the deflection of the needle would be to the left when the exciting 

 coil was moved towards the north pole and back. The amount of 

 motion imparted to the coil determined also the amount of deflec- 

 tion of the needle, and could, by means of a telescope and a scale, 

 be read off in degrees on a reflector attached to the end of the 

 needle. The needle itself weighed 100 Ibs., and was suspended 

 from the ceiling of the room by untwisted silk. Notwithstanding 

 the extraordinary weight of the needle (which was the same as 

 used by Gauss to determine the laws of terrestrial magnetism), 

 its motions were beautifully energetic and distinct when viewed 

 through the telescope. Gauss and Weber did not pretend, how- 

 ever, to the construction of a commercially useful electric tele- 

 graph, but delegated that task to Steinheil of Munich, who enjoyed 

 already at that time a reputation as a skilled mechanic. Steinheil 

 applied himself vigorously to the task, and produced, in 1837, his 

 needle, printing, and acoustic instruments, which he first tried at 

 .Munich through about 5 miles of suspended line wire and shortly 

 afterwards upon the Taunus railway, near Frankfort. In trying 



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