58 



SUBMARINE CABLE LAYING AND REPAIRING-. 



these values for each weight ratio. Having obtained the weight 

 ratio from curve E, all other constants of the core can be 

 found as shown above. 



Fourthly, having given the weight ratio, the same applies, 

 namely, the weight of conductor is obtained by 'curve D, and 

 the rest easily follows as described. 



The curves, of course, vary for every diflferent quality or 

 composition of gutta that may be used. It will be seen from. 



6 0-7 0-8 0*9 1-0 1-1 1-2 1-3 1-4 1-5 1'6 

 Ratios of Weights of Copper to Gutta-Percha. 



Fig, 31. — Curve E, showing Relation between Thickness of Dielectrie 

 and Ratios of Weight of Conductor and Insulator for a K R per Naut of 

 0-865 at 40°F. 



these curves that a core of given ^r maybe made in several ways — 

 as, for example, a large conductor with a thin dielectric or a 

 small conductor with a thick dielectric, or of any intermediate 

 relative dimensions. The core with thick dielectric forms, of 

 course, the most expensive but at the same time the most 

 durable cable. The aim in design is to keep down unnecessary 

 cost without going to the extreme of low cost by making the 

 insulation covering mechanically and electrically weak. 



The cable which can be produced to comply with the limiting: 

 conditions, and which at the same time has the greatest thick- 



