WILL/ AM .s7/-:.J//;.V.v, j-\K.s. 21 



drawing a hemp rope quickly through water. Such a cable it is 

 ditlicult to submerge in deep seas with a sufficient amount of slack ; 

 it will run out with an inclination of perhaps 10 with the horizon, 

 and although the brake may be entirely loosened, it will not slide 

 backward through the water, but will reach the bottom in a straight 

 line, and if there be any irregularities in the bottom, it will have 

 to span them, and be destroyed before long in consequence of a 

 constant strain and complete exposure to corrosive action. Again, 

 if the cable is too heavy, the retaining force would be too great, 

 and serious difficulties would arise. If you suppose a 5-ton cable 

 to be laid to a depth of 2,000 fathoms, a resistance would be 

 required equal to nearly 7 tons. No doubt a sufficiently powerful 

 brake might be constructed, but not even the " Great Eastern " 

 would be able to make headway with such a retarding force behind 

 it, steamers would have to be used to drag the ship forward ; but 

 if any accident should occur, if one of the heavy wires should 

 break, become entangled, the signal "stop" would have to be 

 given, the tug steamers would veer round before the wind, the 

 cable vessel would be dragged backward by the strain of the 

 cable, and collisions and great mischief might arise. A deep-sea 

 cable, then, must neither be very heavy, nor very light, or it will 

 fail. Experience tends to prove that a cable of from one and a 

 half to twice the gravity of water answers the purpose best. In 

 this respect, the new Atlantic cable is very perfect ; it has a 

 specific gravity of about 1*6, combined with great strength ; but 

 on the other hand, it is liable to the accidents through broken 

 wires to which all spiral cables are subject, and, moreover, its 

 durability when laid is not likely to exceed that of the Toulon and 

 Algiers cable, which was of the same construction. The cable to 

 which I referred before, sheathed with copper, has about the same 

 specific gravity as the new Atlantic cable, but is free certainly 

 from the above-named objections. I ought not to proceed, how- 

 ever, without alluding to a failure which took place in submerging 

 a cable of this description between Oran and Carthagena last year. 

 Passiug over an accident of a purely mechanical nature which 

 occurred in the first attempt, the cable was laid successfully from 

 Oran to Carthagena, a distance of 116 miles, but broke a few hours 

 afterwards, 10 miles distant from Carthagena. According to the 

 soundings which had been previously taken by the French Ad- 



