THE WORLD'S A DVAXCE 



195 



four times as thick as the deep-water 

 type. The copper wires are first wrapped 

 with gutta percha, then brass tape ; next, 

 a thickness of jute yarn is applied, fol- 

 lowed by a sheathing of galvanized iron 

 wire, more jute, more wires and a final 

 outer covering of jute-steeped yarn. Ac- 

 cordingly, while the deep-sea" portion of 

 the cable may weigh no more than 2^2 

 tons per mile, the shore end, armored 

 against icebergs, may weigh 60 or 70 

 tons. 



A deep-sea cable jointer must be a 



electrical disturbance which would inter- 

 fere seriously with the transmission of 

 messages. The longest cable with two 

 cores is only a trifle longer than five hun- 

 dred miles. It is laid between Canso, 

 Nova Scotia, and Rockport, Mass. 



Surveying the Bottom of the Sea 



The cost of laying a submarine cable 

 is enormous, so that the greatest precau- 

 tions are observed in order that the thin 

 line of copper lying miles deep does not 

 come in contact with the smallest trickle 

 of sea water. In case any of the numer- 

 ous undersea enemies of the cable should 

 attack the insulation and let the water in, 

 a second necessity arises that of lay- 

 ing the cable so that it can be drawn 

 readily to the surface for repairs. These 

 two problems are solved, first, by making 

 the cable flexible as well as strong, and, 



Below: General View of the 

 Instrument Room at the 

 Far Rockaway Station. 

 The Messages are Received 

 on Paper Ribbons, Thus 

 Comprising a Permanent 



Above: The Cable Station 

 at Far Rockaway, N. Y. In 

 the Circle: A Commercial 

 Cable Company Operator at 

 His Instruments in the Far 

 Rockaway Station. 



man both temperate and healthy. It 

 seems incredible, but nevertheless it is 

 true, that the exudation of the pores of 

 the skin at the finger tips of intemperate 

 or unhealthy workmen contains harmful 

 secretions which will in time rot the 

 gutta percha. 



When the cable is completed, it is 

 coiled with the precision of thread in 

 large water tanks aboard the cable ship 

 in readiness for laying. The largest 

 cable ship is the Calonia, of London, 

 which was used in laying the trans- 

 Pacific cable of the Commercial Pacific 

 Company. The Calonia is 500 feet long, 

 with a capacity of 4,000 miles of cable. 



Cables of any considerable length have 

 only one core, as the nearness of two 

 parallel wires in a circuit several thou- 

 sand miles long would create a powerful 



second, by surveying the sea bottom over 

 which the cable will lie. 



The geography of the ocean floor is in 

 many respects a counterpart of the topog- 

 raphy of dry land. That is to say, there 

 are hills, valleys, plateaus even an oc- 

 casional volcano. The question : does a 

 submarine cable sink to the bottom of the 

 ocean? is answered very emphatically 

 in the affirmative. The waters of the sea 

 are never at rest, and a cable spanning 

 two subterranean mountain peaks would 



