SCIENCE IN THE INDUSTRIAL WORLD 



to determine approximately the position of the fracture 

 by electrical tests from the shore. The repair ship is 

 then sent to the point indicated and the cable raised and 

 repaired. In order to raise the strand the ship drags 

 the bottom transversely with a five-or six-pronged anchor, 

 or grapple, a dynamometer indicating when the cable 

 has been caught. 



In very deep water, unless the cable has been hooked 

 near the broken end, the raising of it directly to the sur- 

 face would cause so great a strain that another fracture 

 would probably result. To obviate this it is raised a 

 certain distance, perhaps half-way to the surface, and 

 then held in position by a buoy attached to the grapple 

 rope. At some little distance from this point the cable 

 is again hooked with another grapple iron, and unless 

 the depth be extreme, may now be brought directly to 

 the surface, as sufficient weight is relieved by the buoy 

 and grapple to allow this to be safely done. In this way 

 repairs may be made with comparative ease and rapidity. 



The life of a submarine cable under ordinary cir- 

 cumstances has not as yet been definitely determined 

 which is the same as saying that it is a long one, since 

 numerous cables have been working continuously for 

 many years, and there is every reason to believe that 

 they will continue doing so for many more to come. 

 They must be constantly attended to and repaired, 

 however, and the cost of these repairs sometimes 

 amounts to fabulous sums. The cable of the Direct 

 United States Cable Company, laid in 1874, has cost, 

 on an average, $40,000 per annum for the last thirty 

 years. 



[44] 



