THE ELECTRIC TELEGRAPH. 



cable in the hold, and round the brake-wheel as the cable passed 

 off in the process of submersion. The shore end having been 

 made fast securely, the steamer was put in motion, and a certain 

 strain was put on the cable by means of the brake-wheel, so that 

 it was laid straight on the ground, or bottom of the sea. 



The cable is seen as it rises from the hold in the foreground, 

 (fig. 34, p. 145,) guided between rollers to the drum, and it again 

 appears in the back ground, as it passes over the stern. A counter 

 and indicator was applied to the shaft of the drum by which the 

 length of cable which at any moment had been delivered off into 

 the sea was shown. 



The wind and tides have the effect of drawing the vessel out 

 of her course, so that the quantity of cable expended must always 

 be greater than the distance between the two points in a straight 

 line. In the case of the Holyhead and Howth cable, the quantity 

 expended was 64 miles. The depth of water is 70 fathoms, being- 

 more than twice that of Dover. 



The entire process of laying it down was completed in 18 hours. 

 In another hour the cable was brought ashore, and put in connec- 

 tion with the telegraphic wires between Howth and Dublin, and 

 immediately afterwards London and Dublin were connected by 

 means of instantaneous communication. 



This cable was lighter considerably than that between Dover and 

 Calais, its weight being a little less than one ton per mile, and 

 consequently its total weight did not exceed 80 tons, while the 

 Dover and Calais cable weighing 7 tons per mile, its total weight 

 was 180 tons. 



From some cause, which could not be ascertained, this cable, 

 after being worked for three days, became imperfect. It was sup- 

 posed to have been caught by the anchor of some vessel, for on being 

 taken up lately, it was found broken near Howth, and the gutta- 

 percha and copper wire stretched in an extraordinary manner. 



83. On the 9th October, 1851, Messrs. JNewall and Co. attempted 

 to lay a cable across the narrowest part of the Irish channel, 

 between Port Patrick and Donaghadee. This cable contained six 

 conducting wires, similar to fig. 43. The distance across is the 

 same as between Dover and Calais, viz., 21 miles, and 25 miles of 

 cable were placed on board the " Britannia " steamer. The pro- 

 cess of submersion was carried on until 16 miles had been 

 successfully laid down, when a sudden gale came on, which 

 rendered it impossible to steer the vessel in the proper course, and 

 Mr. Newall was reluctantly compelled to cut the cable, when 

 within 7 miles of the Irish coast, and having 9 miles of cable 

 remaining on board. 



The whole of this 16 miles of cable has been recovered in 

 156 



