6-44 THE INVENTORS OF THE TELEGRAPH AND TELEPHONE. 



scale." And further oil iu the same report: "The ease and certainty 

 with which the manipulator has the direction of the current, and there- 

 fore the movement of the magnetic needle, in his command, by means 

 of the communicator, had a year ago suggested experiments of an 

 application to telegraphic signaling, which, with whole words and even 

 short sentences, completely succeeded. There is no doubt that it would 

 be possible to arrange an uninterrui)ted telegraph communication in 

 the same way between two places at a (considerable number of miles 

 distance from each other." 



The method of producing the currents in (iauss and Weber's exper- 

 iments was an application of the important discoveries of Faraday 

 and Henry in the induction of currents by currents and by magnets, 

 which have since borne so very important fruit in the held of dynamo- 

 electric machinery. 



On the recommendation of Gauss this telegraph was taken up by 

 Steinheil, who, following their example, also used induced currents. 

 The important contributions of Steinheil were the discovery of the 

 earth circuit, made while attempting to use the rails of a railway as 

 telegraphic conductors; the invention of a telegra])hic alphabet and a 

 recording telegraph. Of these the discovery of the earth circuit, made 

 in 1837, has proved of great value. An interesting description of 

 SteinheiPs telegraph, together with illustrations of the magneto-electric 

 and recording apparatus used on the line erected in 1837, between 

 Munich and Bogenhausen, Avill be found in Sturgeon's Annals of 

 Eleclr'iclfy (vol. iii). This account, written, by Steinheil himself, 

 shows that he had at that time an excellent appreciation both of the 

 mechanical and electrical i)roperties wliich a good practical electric 

 telegraph should ha^'e, and also that he was well versed in the knowl- 

 edge then existing of electrical science. The relative merits of scopi*-, 

 acoustic, and recording telegraphs are discussed, and the advantages, 

 which experience has since brought into prominence, of the acoustic 

 telegraph is pointed out. A very good discussion of the most econom- 

 ical method of arranging signals for a telegraphic alphabet will also 

 be found in this pai>er. 



Schilling's telegraph, which we have just seen, was the model on 

 which Gauss and Weber's, and, therefore, also Steiuheil's telegraphs 

 were based, was, as we shall see presently, also the basis of Cooke's, 

 and of Cooke and Wheatstone's needle telegraphs. 



Previous to the date which w^e have now reached (1837), anotlier 

 epoch-making diseovery had been made, which has had great influ- 

 ence on telegiaphy. Tliis was the discovery of the magnetizing 

 influence of the current. The discoNcry of Oersted was followed by 

 Ampere in a long seri<'s of researches, in which, among other things, 

 he establishe<l the mutual attractions and repulsions of wiies carrying 

 <'urrents, tlie iact that tlu' voltaic element itself acts on a magnet like 

 any other part of the circuit, and that a spiral of wire fiu-ming part 



