244 ELECTRO-TELEGRAPHY 



iron-wires. The whole rope was capable of sustaining a strain of aboiit 50 tons ; it 

 weighed 7 tons per mile, making a total weight of nearly 600 tons. It was made by 



816 817 



Cable from Dover to Ostcnd From Port Patrick to Donapfaadee 



(1853. Length 70 miles), (1853. Length 2 5 miles), 



and Zuyder Zee, 5 miles. and Spezzia to Corsica, 110 miles. 



Newall and Co., in 100 days, its cost being 33,0002. It required 70 hours to coil it 

 into the ship, and it was submerged in the sea, from Dover to Ostend, in 18 hours. 

 The arrangement of the inner wires did not prove entirely satisfactory. 



After the success in sinking the Dover and Ostend cable, Messrs. Newall and Co. 

 commenced laying a cable from Donaghadec, in Ireland, to Port Patrick, in Scotland, 

 across the Irish Channel. This cable was of the same weight and size as fig. 816, but 

 the conducting wires were differently arranged, as seen in fig. 817. The drawings 

 given are of the natural size. This cable was made in twenty -four days, and at a cost 

 of 13,000. The Mediterranean cable is of the same construction as that across the 

 Irish Channel, and was laid in 1854. This line runs from Spezzia to the Island of 

 Corsica. Over this there is a land-line extending to the Straits of Bonifacio, where a 

 short submarine line of 7 miles runs to the Island of Sardinia. Across this island 

 there is a line 203 miles long, terminating at Cape Spartivento. The telegraphic com- 

 munication between the Island of Sardinia and Africa seems to have been surrounded 

 with great difficulties. Two attempts were unsuccessful ; but the third proved, by its 

 .success, that perseverance accompanied by judgment usually attains the end desired. 

 This cable, also made by Messrs. Nowall, was composed of 4 sets of conducting 

 wires, and these, in the deep-sea portion, were protected by 18 iron-wires, while 

 the shore-end was surrounded by 12 much stouter wires. The shore-cable was 6 miles 

 in length. The distance between Cape Spartivento in Sardinia, and Bona on the 

 African coast, is 125 miles. Messrs. Newall and Co. also made the cable which 

 unites Malta and Corfu with Sardinia. The electrical cord in this cable is com- 

 posed of 7 small wires twisted together and insulated by a thick layer of j_ r utt;i- 

 percha. The deep-sea portion is protected by 18 small iron-wires ; while the shore- 

 end is covered by an armour of 10 stout iron-wires, and which is consequently 

 much heavier than the deep-sea cable. The weight of the deep-sea section of this 

 cable is 1,960 Ibs. per mile, and its total cost was 125.000J. These may be n 

 as typical examples of nearly all the submarine electrical cables which have been 

 laid. 



It becomes necessary to give a little more in detail the description of the Atlantic 



cable of 1858 (fig. 818). The 

 electrical conductor was a copper 

 8trantl > consisting of 7 wires 6 

 laid round 1, forming in f 

 far as electricity is concern. :. 

 1 wire. This weighed 10; 



r nautical mile of 2,028 yaHs. 

 was carefully insulated with 



The Atlantic Cable, 1858. Length 1670 miles. pitta-Vereha.laidon in Scontinps, 



and weighing 261 Ibs. per Tiautieal 

 mile. Eighteen strands of charcoal iron-wire each strand composed of 7 wires. G laid 

 round 1 laid spirally round the core. This was, however, previously padded with 

 a serving of hemp, saturated with a mixture of Stockholm tar. The weight of this 

 cable in air was 20 cwte. per nautical mile, while in water it was only 13-4 cwts. This 

 made it equal to 4'85 times its weight in water ; or capable of bearing its own weight 



