CHAPTER XVII. 



SUBMARINE CABLES. 



The first attempts at transmitting messages 

 through wires laid in water were made about 

 1839. These early experiments were not very 

 successful, because the art of wire-insulation 

 had not attained any degree of perfection at 

 that time. It was not until gutta-percha be- 

 gan to be used as an insulator for submarine 

 lines that any substantial progress was made. 



The first line, so history states, that was suc- 

 cessfully laid and operated was across the 

 Hudson River in 1848. This line was con- 

 structed for the use of the Magnetic Telegraph 

 Company. 



In the following year experiments with 

 gutta-percha insulation were successfully 

 made, and about 1850 a cable was laid across 

 the English Channel between Dover and Calais 

 (twenty-seven miles), consisting of a single 

 strand of wire having a covering of gutta- 

 percha. The insulation was destroyed in a 

 day or two, which demonstrated the fact that 

 all submarine cables must be protected by 

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