ll-'JLL/AM SIEMENS, FJLS. J 



'atfcendre I'auoompluninsat d'un but aussi vaste quo le notre par 

 des moyens tellement limites, sans dcs delais et des contrarietcs de 

 clifU'Tents genres. L'histoire de toutes les inventions importantes 

 est 1'histoire d'un progres graduel et d'une perseverance 6clairee de 

 la part dcs entrepreneurs. Pour ina part j'ai devoue a cettc affaire 

 non settlement la plus grand e par tie de mon temps (et inon temps 

 est un capital dans la position oil je me trouve), mais j'ai devoue 

 encore tout 1'argent que j'ai tire de la Societe et celui de mes 

 moyens particuliers. Je crois qu'il m'est permis de faire valoir 

 cette circonstauce, plutot personnelle, melee a un rapport officiel 

 parceque je la regarde comme un titre a votre corifiance, et comme 

 une assurance pour la reussite complete de notre entreprise. 



(Signe) C. W. SIEMENS. 



LONDRES, 4 Mai, 1857. 



DEEP SEA TELEGEAPHS. 

 By C. W. SIEMENS.* 



ON coming forward to address you on the subject of deep-sea 

 telegraphs, it is necessary for me, in the first place, to define my 

 subject by drawing the distinction between deep-sea lines and 

 submarine telegraphs in general. 



The characteristics of a shallow sea-line are, firstly, that the 

 iron sheathing usually applied has abundant strength to support 

 the cable during the operation of submersion, as also for raising 

 the same again to the surface for the purposes of repairs ; secondly, 

 that it admits of being divided into sections of convenient lengths 

 for the transmission of messages ; and lastly, that it lies within 

 reach of abrasion from currents, or even ship's anchors, and has 

 to be made strong enough to resist these mechanical agencies. 



The deep sea lines, on the contrary, lie virtually beyond the 

 reach of accident, and in perfect calm at the bottom of the sea , 

 they require, therefore, less absolute strength, but a greater 

 amount of relative strength, to support their own weight in sea 



* Excerpt Journal of the Royal United Service Institution, Vol. IX. 1865, 

 pp. 459-471. 



