THE LAYING OP SUBMARINE CABLES. 119 



that their tanks, if full, would hold enough armoured cable to 

 sink them. 



The length of each type of cable is accurately measured 

 before it leaves the factory, and marks are put on at each 

 nautical mile with numbers attached, representing the number 

 of miles manufactured, the numbers being in a separate series 

 for each type, and known as the factory mile marks. These 

 are afterwards of great use in checking the drum measurements 

 of cable as laid. The exact position of all the factory splices 

 is also noted. 



The tests on completed gections in the factory tanks are 

 repeated on board, cable being under water in ship's tanks. 

 These tests at tank temperatures are afterwards corrected to 

 the standard of 75°F., at which the original core tests in 

 factory were made. The latter are usually spoken of as " the 

 seventy-fives." 



Landing Shore End. — On arrival at the place from which 

 the cable is to be laid, after meeting the officials representing 

 the port, the Town Authority and the Cable Company, and 

 arranging preliminary details of form, tne first work to be 

 done is to decide upon a landing place, erect and equip the 

 cible hut, and liud the shore-end. Soundings are taken from 

 a steam launch, and a position for landing the end at once 

 decided upon, away from the general anchorage and free from 

 shoals, banks and wrecks. The presence of rocks can be 

 detected by dragging a grapnel along the bottom. Three or 

 four mark buoys are then put down to indicate the route 

 chosen. A suitable position is then found by soundings for the 

 ship to anchor in. 



If the weather is favourable, and there is not a high surf 

 running, in most cases it is preferable to land the end by means 

 of a lighter and steam tug. A hulk or lighter capable of 

 carrying 40 to 50 tons, and drawing not more than 6ft. or 8ft. 

 of water, is engaged and brought alongside the ship. If the 

 hold is not convenient for coiling, a strong platform to receive 

 the cable is built on the lighter by the ship's hands. 



A paying-out sheave, friction table and hawsepipe are fixed 

 aft on a pair of stout baulks bolted to cross timbers, and 

 secured firmly to the deck, as sketched in Fig. 56. The 

 friction table consists of smooth round surfaces of cast iron 



