Figure 6. — Soemmerring's electrochemical telegraph of i8og, 

 general view. From Die kbnigliche Akademie der Wissenschaften 

 zu Miirwhen, Denkschrijten, i8og-i8io, vol. 2, pi. 5. 



the realization of such a device had been taken. This 

 first step was the easiest and the one that only a suc- 

 cessful inventor could get beyond. Two problems 

 involved in signaling by means of an electric current 

 had to be overcome in order to produce a workaijle 

 electromagnetic telegraph. 



The work of Soemmerring and Ampere had pro- 

 vided inventors with two distinct means of detecting a 

 signal by means of electricity. It was no difficult task 

 to transmit a signal within the confines of a room, but 

 it was impossible to produce an effect across a distance 

 of several miles if just an arbitrary combination of coils 

 and batteries was used. Moreover, the telegraphs of 

 Soemmerring and Alexander used 20 to 30 wires. If 

 the messages were to be exchanged between cities 

 miles apart, there was the very considerable economic 

 problem of installation and maintenance of the cir- 



cuits as well as the technical problem of providing 

 appropriate material for the wire and the proper in- 

 sulation. Yet these problems of signaling at a dis- 

 tance and of reducing the great number of wires re- 

 quired for transmitting signals had to be solved if any 

 commercial application of the telegraph was to be 

 rrade. 



Because of the imperfect state of electrical theory, 

 it was usually a little time after the invention of a 

 signaling device before its inventor appreciated that 

 these problems of distance and economy existed. 

 Eventually it was learned that the proper combina- 

 tion of batteries and magnets (impedance matching) 

 solved the problem of transm.itting signals over long 

 distances. It was also learned that the great number 

 of lines required could be reduced by the use of a 

 binary code, which was based on the two conditions 



PAPER 29: DEVELOPMENT OF ELECTRICAL TECHNOLOGY IN THE 19TH CENTURY: II 



279 



