, MECHANICS AND USEFUL ARTS. 23 



embedded in Chatterton's compound. Insulation was effected 

 with gutta percha and Chatterton's compound. Weight, 400 lbs. 

 per nautical mile. The outer coat was 10 wires drawn from 

 Webster and Horsfall's homogeneous iron, each wire surrounded 

 with tarred Manila rope, and the whole laid spii-ally around the 

 coi'e, which had previously been padded with a serving of tarred 

 jute yarn. Breaking strain, seven tons, 15 cwt. ; capable of 

 bearing its own weight in 11 miles depth of water. Length of 

 cable, 2,300 nautical miles ; diameter, one inch. 



The cable of 1866 has for a conductor a copper strand of seven 

 wires, six laid around one ; weight, 300 lbs. per nautical mile ; 

 embedded for solidity in Chatterton's compound. The insulator 

 is four layers of gutta percha laid on alternately with thinner lay- 

 ers of Chatterton's compound ; weight, 400 lbs. per nautical mile. 

 The outer coat is 10 solid wires drawn from Webster and Hors- 

 fall's homogeneous iron and galvanized, each wire surrounded 

 separately with five strands of white Manila yarn, and the whole 

 laid spirally around the core, which had previously been padded 

 with a serving of tarred hemp. The breaking strain is eight 

 tons two cwt., and it is capable of bearing its own weight in 12 

 miles depth of water. The length of this cable is 2,730 nautical 

 miles, part of which was to be used for completing the cable that 

 parted in 1865. Diameter, one inch. 



In laying the Atlantic cables, four main risks had to be encoun- 

 tered, all of which in the present one have been successfully 

 passed throuo-h ; 1st, the successful and rapid laying of the shore 

 end ; 2d, passing down the tremendous submarine incline known 

 as the "Irish bank;" 3d, passing over a short steep valley, 

 where the water sinks to almost as great a depth as in mid-ocean ; 

 4th, and greatest, the laying of the cable for a distance of more 

 than 100 miles through a depth of 2,400 fathoms, or 15,000 feet of 

 water ; this passed over, the ocean begins gradually to shallow to 

 100 fathoms on the Newfoundland coast. The present cable was 

 landed on the American coast in 50 fathoms in Heart's Content 

 Bay, one of the most easterly spurs of rocky headland on the 

 south of Newfoundland ; the place chosen for its landing is a 

 deep, rocky inlet, similar to but much larger than Foilhommerum 

 Bay, on the Irish end of the cable ; this is more sheltered than 

 Bull's Bay, where the cable of 1858 was successfully landed. 



The European shore end of the cable of 1866 was landed at 

 Foilhommerum Bay, on the coast of Ireland, July 7, 1866, at 

 ^noon ; by 3 A. M. of the 8th, the full length of 30 miles was paid 

 out, signalled through, and its insulation and conductivity found 

 perfect. On July 12th, the " Great Eastern " commenced making 

 the splice with buoyed shore end : as Boon as that was completed 

 and found perfect, the great work of laying the cable commenced. 

 For the first 250 miles, that is till over the " Irish bank," the cable 

 made in 1865 was used, after that the new cable only ; the reason 

 for making this difterence was that the new cable is more strongly 

 made than that of 1865, and was therefore reserved for the deepest 

 water. The route taken was 30 to 35 miles south of the broken 



