Advance in Cable-Laying.— With two cables now linking America and Great Britain, confidence was restored, and the manufacture and successful laying of submarine cables went on at a rapid rate. In 1869 a line was laid from Brest, France, to Saint Pierre, New foundland (a distance of 3,100 miles), by a French company. In 1873 a cable joined the cities of Lisbon and Pernambuco, and in 1874 and 1875 two more cables were laid between Valentia and Heart's Content. The latter weighed less than 900 pounds per mile. Another line from Penzance, Cornwall, to Saint Pierre, 2,920 miles, was laid in 1879, and one from England to Panama in 1882.
Meanwhile an incident had occurred which greatly influenced the expansion of submarine cable systems. In 1870 the British government purchased the entire land telegraph system of the British Isles, and the capital thus liberated, about $50,000,000, was largely reinvested in submarine cable ventures. In 1872 a number of small competing companies with lines through the Mediterranean were consolidated into the Eastern Telegraph Company, and in the follow ing year the Eastern Extension, Australasian & China Telegraph Company was formed by the amalgamation of companies owning cables farther east. Since then the Eastern, Eastern Extension and Associated Cable companies have become practically one immense organiza tion.
In 1884 John W. Mackay and James Gor don Bennett organized a cable system across the Atlantic from Valentia to Torbay, N. S., in the interests of the Commercial Cable Company and the New York Herald. Consolidation of competing companies followed as a matter of course, and now there are practically, besides the French lines, but two competing cable com panies in the north Atlantic field—the Anglo American and the Commercial Cable companies. There are now 15 cables between North Amer ica and Europe, some of which run into New York harbor. The cables of 1858, 1865 and 1866 are edead,s and three others have but a brief tenure of life. Nine are ealives and active.
About 1902 France undertook to lay cables to connect her colonies, and now has over 12,000 miles in operation. A little later the Commercial Cable Company laid its fourth line to connect New York and London; by way of Rockport, Mass., Canso, N. S., and Water ville, Iceland. The European War put a check on cable-laying for several years.
Pacific Cables.— In the Pacific Ocean the Commercial Company has constructed a cable 6,912 miles long and costing $12,000,000, laid from San Francisco, via Honolulu, the Mid way Islands and Guam to Manila, in the Philip pines, with an ultimate extension to Shanghai or Hongkong. The . first section, from San
Francisco to Honolulu, 2,413 miles, was opened 1 Jan. 1903. This section is the most hazardous on the route, depressions of 5,160 and 5,269 fathoms having been encountered, and the pro file displaying mountains of immense elevation and valleys of corresponding depth. A level plain, with an average depth of 2,700 fathoms, extends throughout the second section, from Honolulu to the Midway Islands, the bottom being of soft mud and extremely favorable for cable-laying. Thence toward Guam an average of 3,200 fathoms is found, and favorable con ditions are maintained throughout. The last section is similar in its profile to the first, though the depth averages less, being from 1,400 to 2,700 fathoms. The sea-bed is ex tremely irregular in outline, with many reefs and depressions.
The cable is built around a core formed of copper wire insulated by gutta-percha, around which layers of jute yarn are wound. This, in turn, is sheathed in small cables, each formed of several strands of steel wire. An outer covering of jute yarn, the whole saturated with a bituminous compound, binds together the con ducting and protecting wires in one solid mass. The landing of the shore end of the cable at San Francisco was effected thus: A section of six and one-half miles was cut from the main cable on board the cable-steamer Silvertown and loaded on a tender, which steamed toward the shore. On approaching the line of breakers, which were heavy, the shore end was floated on balloon buoys placed every 10 fathoms, and a team of 12 horses dragged it ashore, where it was spliced to the permanent shore connection, and the tender returned to the Silvertown, on board which the shore section was respliced to the main cable. The cable-ship then started for kIonolulu in the evening of 14 Dec. 1902.
The Silvertown was specially built for cable laying purposes. On this trip she carried 2,413 nautical miles of cable, weighing 4,807 tons. She arrived off Honolulu on 25 December and landed the shore end by buoying the cable; but she employed no tender or horses. Two spider-sheaves were sent ashore and fixed by sand anchors about 60 yards apart. A hauling line was paid out from the ship, reeved through the sheaves and brought on board again. One end of this line being attached to the cable and the other to the picking-up gear, the engines were started and the cable was dragged toward the shore.