SSfi WILL/AM SfEMENS, F.R.S. 9! 



fact, tending to inspire the public mind with fresh confidence in 

 long lines of ocean telegraph. The author having been employed 

 by Her Majesty's Government, as the electrician to superintend 

 the manufacture and shipment of this cable, can testify to its actual 

 state of insulation, at the different stages of its progress, and to its 

 general superiority as compared with former lines. The methods 

 of testing employed differed essentially from those resorted to on 

 former occasions ; and although the system adopted was very much 

 relaxed towards the conclusion of the work, it has contributed, 

 nevertheless, to the establishment of a long submarine telegraph 

 cable, far surpassing former attempts in apparent permanency and 

 in transmitting power. 



At the time the Atlantic Cable was manufactured, little was 

 known of the requirements for such a line. The electric conductor 

 was insufficient in size, and its insulation was so imperfect, even 

 before it was shipped for its destination, that its momentary and 

 partial success appears, at present, more surprising, than its sub- 

 sequent entire failure. Since then, the Red Sea and India tele- 

 graph cable has been laid, in the years 1859 and 18GO, without 

 permanent success. The size of the conductor and the thickness 

 of the insulating material were, in the latter case, well proportioned 

 to the length of the intended sections of the line, which were not to 

 exceed GOO miles. Some of the sections are asserted to remain in 

 good working condition up to the present time, while others began 

 to give way nine months after they were submerged, from causes 

 which will partly be dealt with hereafter. 



The author's connection with the Red Sea and India Telegraph 

 was limited to the period of submerging the cable, when the firm 

 with which he is connected undertook to superintend the electrical 

 supervision and instrumentation of the line, on behalf of the con- 

 tractors, Messrs. R. S. Newall and Co. Its insulation when laid, 

 was superior to any previously manufactured, although it did not 

 nearly approach the standard of comparative perfection, which 

 has been reached with the same material, in the case of the Malta 

 and Alexandria line. The latter may be said to be the first which 

 was tested systematically during the progress of its manufacture 

 and shipment ; and had the same system of tests been continued 

 during the outward voyage, and when submerging the cable, a 

 valuable record might have been obtained, throwing additional 



