.S7A- ll'//.UA.\r SIEMENS, J-\K.S. 33 



the receiving instrument, and moreover, that the positive and 

 negative impulses are equal in amount. 



The success of a long submarine line of electric telegraph 

 (l.-jt'-nds also in a great measure upon the particular construction of 

 both the communicating and receiving instruments. On this 

 point I am in a position to speak from extensive experience, being 

 with ;ni establishment which had to contend at an early 

 with the difficulties experienced upon long underground 

 lines, which has since carried out extensive systems of telegraphs 

 in Russia and other countries, and has furnished the instruments 

 of most of the continental lines, including those in Turkey, India, 

 and Australia. In addition to this there is the experience of the 

 Black Sea and the Mediterranean lines, which are the longest 

 submarine lines hitherto constructed, with the instrumentation 

 of which I was charged by Messrs. Newall & Co., the successful 

 contractors of those undertakings. 



Morse's recording instrument combines, as stated before, many 

 practical advantages which recommend it for universal adoption 

 for all mercantile lines, among which advantages is the facility it 

 offers of forwarding messages at intermediate stations without the 

 intervention of a clerk, in putting on a fresh battery, a system 

 first introduced by Siemens and Halske, and perfected by Stein- 

 heil, by which it is made to speak directly between London and 

 the remote parts of Russia. 



The real telegraphic receiving instrument is the relay, which has 

 for its duty to establish and break the local circuit of the recording 

 instrument. 



An important point in the construction of a delicate relay was 

 the suppression of the armature of the electro-magnet employed 

 (patented by "Werner Siemens in 1851) by allowing one of the two 

 upright bars of soft iron composing the horse-shoe electro-magnet 

 to vibrate upon delicate points, and producing rotary motion by 

 the attraction between approximated horizontal arms extending 

 from the same. The application of magneto-electric currents 

 necessitated a corresponding change in this relay ; for, however 

 sensitive it might be made, it was necessary that the effect of the 

 line-wire current should be continued till the recording instrument 

 has had time to make a dot or line upon the paper, and the 

 magneto-electric current, being nearly instantaneous, is unsuited 



VOL. II. D 



