December 18, 1885.] 



SCIEJSrCE, 



545 



LAYING A CABLE. 



It was not much of a cable, after all, and its 

 laying was no gTeat performance, although forty 

 years ago it might have been considered a 

 marvel. 



Science, in its so-caUed practical aspects, is now 

 advancing in parallel lines ; and these are so 

 numerous, and some of them so far-reaching, that 

 most men are unable to follow along more than 

 one or two. This fact has suggested the idea that 

 there may be something of interest to many in a 

 description of this cable, and of the operation of 

 putting it in the water. 



It does not connect us with any foreign country ; 

 it does not complete the girdle round the earth : 

 it is modestly content to serve as the link which 

 joins the intelligence of the rest of the world with 

 that of the interesting and important islands, 

 Martha's Vineyard and Nantucket, where for- 

 merly the influence of the whale prevailed over 

 aU else, but now, alas ! tributary to the state of 

 Massachusetts, from which comes good govern- 

 ment, and to the Standard oil company, from 

 which comes petroleum, that arch enemy of the 

 whale trade. But exclusiveness, even when aided 

 by insulation, must give way to the progress of 

 events. A glance at the map will show the nature 

 of the forces operating in this case. Vineyard 

 Sound is the gi-eat highway of the coasting trade. 

 Thousands of vessels of all kinds pass through it 

 every year. The harbors of Vineyard Haven (cor- 

 rectly named). Tarpaulin Cove, Lambert's Cove, 

 etc., afford shelter for hundreds during rough 

 weather. Wrecks are, unfortimately, not infre- 

 quent ; and a visitor from the outside world is 

 likely to see in the simple but perfectly neat and 

 thrifty-looking home of the fisherman-farmer a 

 carved and upholstered chair, or something of the 

 kind, which is referred to with no little pride as a 

 relic from the wreck of some passenger-steamer 

 which went ashore with the loss of many lives and 

 much property upon the coast near by. 



The principal and sufficient reason for asking 

 for a special appropriation from congress to secure 

 telegraph communication with the mainland, was 

 that stations of the U.S. signal service might be 

 established on the islands, and particularly that 

 danger-signals might then be displayed from the 

 more prominent points for the guidance of the 

 numerous sailing-craft constantly passing through 

 the sound. Some years of effort were rewarded 

 with success at the last session, an appropriation 

 of forty thousand doUars having been made for 

 the purpose of laying the necessary cable, amount- 

 ing in all to less than thirty miles, and for erecting 

 the land-lines, dis^jlay-stations, etc. The work has 



been done, therefore, under the direction of the 

 chief signal-officer. 



The cable was made in London, and shipped to 

 New York in the hold of a steamer, coiled in two 

 large tanks especially built in the steamer for that 

 purpose. It fortunately happens that the gutta- 

 percha insulation, used almost exclusively for sub- 

 marine cables, is improved and preserved by being 

 kept damp, cracking and deteriorating when dry. 

 For this reason it is necessary to keex^ the cable in 

 tanks during its passage, so that it may be kept 

 covered with water. The conducting part of the 

 cable consists of seven copper wires, each about 

 .028 inch in diameter, six being twisted about the 

 seventh as a centre. The resistance of this con- 

 ductor was not to exceed thirteen ohms per nau- 

 tical mile, and it fell considerably short of that 

 upon being measured. This copper core was 

 covered with three or four layers of gutta-percha, 

 until the diameter of what might be called the 

 cable proper w^as a little more than a quarter of 

 an inch. Such a cable would scarcely last while 

 it was being put down, and it is therefore neces- 

 sary to put an ' armor ' upon it, so that it may be 

 able to endure the destructive agencies to which 

 it is likely to be subjected. The gutta-percha- 

 copper core is wound with two or three layers of 

 heavy jute twine, and this, again, with twelve 

 number five galvanized iron wires laid on spirally. 

 The result is apparently a strong h'on rope about 

 an inch and a quarter in diameter. 



An examination of the cable was made in New 

 York City, before its removal from the tanks re- 

 ferred to, for the purpose of seeing that its iasu- 

 lation was still intact. It was then transferred to 

 a barge lying alongside, from which it was to be 

 laid, and in which it was towed tln-ough the sound 

 to Vineyard Haven. Its arrival at tliis place caused 

 little less than a sensation. The first section of 

 the cable was to be placed across Vineyard Sound : 

 and, although not the longest, it was the section 

 likely to cause the greatest anxiety. In fact, the 

 Western union telegraph company has several 

 times tried to place and maintain a cable from 

 West Chop light on Martha's Vineyard to Nobska 

 Point on the mainland, but their efforts have not 

 been altogether successful. The damage to a 

 cable across the sound arises from two sources. 

 The tidal current is strong, at some points neai-ly 

 three miles per hour ; the seaweed, which is car- 

 ried back and forth by this current, is caught on 

 any suspended or exposed part of the cable, and 

 twisted around it until huge, solid masses are 

 attached to it, which offer so much surface to the 

 swift cuiTcnt that the cable must give way under 

 the strain. The other source of danger is quite 

 as disastrous, and nearly as uncontrollable. It 



