HENRY AND THE TELEGRAPH. 293 



" Quite recently I made the discovery tliat tbe ground may be em- 

 ployed as one-lialf of tlie connecting chain. As in the case of frictional 

 electricity, water or the ground may with the galvanic current form a 

 portion of the connecting wire. Owing to the low conducting power of 

 these bodies compared with metals, it is necessary that at the two places 

 where the metal conductor is in connection with the semi-conductor, the 

 foraier should present very large surfaces of contact. Taking water for 

 instance to conduct two million times worse than copper, a surface of 

 water proportional to this must be brought in contact with the copi^er, 

 to enable the galvanic current to meet with equal resistance in equal 

 distances of water and of metal ; for instance, if the section of a copper 

 wire is one-half of a square line, it will require a copper plate of 61 square 

 feet of surface in order to conduct the galvanic current through the 

 ground as the wire in question would conduct it : but as the thickness 

 of the metal is quite immaterial in this case, it will be always within 

 our reach to get the requisite surfaces of contact at no great expense. 

 Not only do we by this means save half the conducting wire, but we can 

 even reduse the resistance of the ground beiow what that of the s^'ire 

 would be, as has been fully established by experiments made here with 

 the experimental telegraph."* 



In his account of these valuable contributions to both the science and 

 the art of electric telegraphy, Steinheil modestly assigns to his immedi- 

 ate predecessors the credit of the most important advancements in the 

 system. He says: "To Gauss and Weber is due the merit of having, in 

 1833, actually constructed the first simplified galvano-magnetio telegraph. 

 It was Gauss who first employed the excitement of induction [magneto- 

 electricity], and who demonstated that the aj^propriate combination of a 

 limited number of signs is all that is required for tlu^. transmission of 

 communication, t Weber's discovery that a copper wire 7,400 feet long, 

 which he had led across the houses and steeples at Gottingen, from the 

 Observatory to the Cabinet of Natural Phdosophy, required no si^ecial 

 insulation, was one of great importance. The principle was thereby at 

 once established of bringing the galvanic telegraph to the most conven- 

 ient form. In accordance with the i)rinciples we have laid down, all that 

 was required in addition to this was to render the signals audible ; a task 

 that ai)i^arently presented no xery particular difiiculty, inasmuch as in 

 the very scheme itself a mechanical motion — namely the deflection of a 



liausen, in Germany, using iron wire conductors, and the earth for a return circuit. 

 This discovery was pnhlished in 18157, in German, and translated into English by 

 Julian Guggsworth, November 24, 1838." (Prescott's Hist. Elcctv. Telcfimph, 1800, chap, 

 xxi, p. 405.) An account of Steinhcil's telegraph was read before; i he French Academy 

 of Sciences, Sej)tember 10, 18158. (Comptes liendtis, vol. vii, pp. 590-593.) 



*Steiuheil's paper "On Telegraphic Communication:" translated from the German, 

 November 24, 1838, by Julian Giiggsworth. Sturgeon's Annals of ElectricUy. etc. 

 April, 1839, vol. iii, ]». 512. A full description of Steiuheil's telegraph is given in Dv. 

 Julius DviWs Amoendun (J dcs Elcktrom(t(jnttismus, Berlin, 1863; 2d edition, 1873, sect, v, 

 pp. 339-347. 



t These statements do not however do justice to Schilling's nuudi earlier "simpli- 

 fied galvano-maguctic telegraph," with which Steinheil was very imi)erfectly ac- 

 quainted. 



