86 THE ELECTRIC TELEGRAPH. 



itself in every country where the telegraph is to be found an 

 employment exceeding that of any other system. The adop- 

 tion of the Morse instrument by the French Administration 

 of Telegraphs in 1857, gave an impetus to inventors, and 

 many real improvements were the result. 



60. Embossing Instrument with movable Magnet. This is a 

 construction of the Morse by Messrs. Siemens and Halske, 

 of Berlin, once extensively used on the Russian, Danish, 

 and some of the German lines, but at present replaced to a 

 great extent by newer constructions. The movement of 

 the writing-lever is effected by the attraction of the opposite 

 poles of two electro-magnets rendered active by the same 

 currents. 



Fig. 45 gives a perspective view of the instrument, m m' 

 are two straight electro-magnets. The core of m is fur- 

 nished with a facing of soft iron, r, on each of its poles ; the 

 core of m is supported between two screw-points, and is 

 furnished at each end with a continuation, p, ending in a 

 facing opposite to and of the same size as r. Between the 

 two continuations p p, is a frame carrying the printing lever. 

 a b and a b' are the ends of the coils of the electro-magnets 

 connected electrically with the terminals A and B. 



When a current traverses the coils it polarises their cores 

 in reverse directions, that is to say, when the end and 

 continuation p of the core in front are south-polar, the 

 corresponding end of the other core, with its continuation r, 

 will be rendered north-polar the reverse polarities being, of 

 course, at the further end and the faces of p and r on each 

 side, having opposite magnetism, will attract each other. 



The attraction of these four poles in the same sense 

 renders the instrument extremely delicate, and the force 

 with which the poles tend to approach each other being 

 very great, the instrument is well adapted for recording 

 signals by scoring the style into the paper strip. 



When the current ceases the printing-lever is brought back 

 by means of the spring /. w w' are the rollers between which 

 a paper strip is drawn. The style, carried at one end of the 

 beam, enters a groove in the middle of the roller w, when 



