SECT. XXXII. ATLANTIC TELEGRAPH. 327 



percha representing the glass. As the power of induction is pro- 

 portional to the tension of the electricity, and as the tension is 

 continually diminished by the resistance of the wires, the induc- 

 tion is continually diminished and requires a longer time. Elec- 

 tricity took two seconds to pass through a cable 768 miles long, 

 laid under ground from London to Manchester, and back again 

 twice ; while in air it was all but instantaneous, because the induc- 

 tive capacity of air is very much less than that of water or moist 

 earth. In the experiment with the cable under ground it took two- 

 thirds of a second to overcome the resistance of the wires, and 

 then the velocity of the electricity was 1000 miles in a second, 

 and it was the same whatever the intensity of the electricity. 



It has already been mentioned that the efficiency of the electric 

 telegraph depends upon the breaking and renewing the current 

 of electricity by means of which a succession of waves of elec- 

 tricity are sent through the conducting wires. Now it has been 

 ascertained that three electric waves may travel simultaneously 

 through the wires of the Atlantic telegraph with sufficient inter- 

 vals between them to record the indications they are intended to 

 convey ; that is, three signals can be intelligibly and practically 

 transmitted in two seconds. 



The original design, structure, and difficulty of depositing the 

 cable are only equalled by the talent and perseverance with 

 which it has been done. The 5th of August, 1858, will be 

 memorable for the accomplishment of the boldest enterprise that 

 ever was undertaken by man, and which is only the beginning 

 of a vast submarine communication that will ultimately encircle 

 the globe. It has been granted to British genius thus to annihi- 

 late time and space, in order to connect all mankind into one 

 great family for their moral and religious advancement ; and, 

 whatever may be the fate of the British Islands in the course of 

 ages, to their energetic race the glory will remain of having 

 been the chief instruments in the hands of Providence for the 

 civilization of the world a civilization which will extend with 

 the development of their numerous colonies into great inde- 

 pendent Christian states, like those of the Union in North 

 America. The thunderbolt snatched from heaven by Franklin 

 now passes through the depths of the Atlantic as a messenger of 

 peace between the kindred nations.* 



* " Eripuit fulmen Coelo, sceptruinque tyrannis," is the inscription on a 

 medal struck in honour of Franklin. 



