206 CARTAGENA-GRAN COPPER-ARMED CABLE. 



terranean a large part of the hemp covering the con- 

 ductor insulated by gutta-percha was eaten away 

 before the end of the year. Moreover the little 

 animals had frequently attacked the gutta-percha itself, 

 and there were numerous places where they had bored 

 right through to the copper, and thereby entirely 

 destroyed the insulation. Even an iron sheathing does 

 not completely prevent destruction by the wood-worm 

 of a cable laid in shallow water, as places at which 

 an outer wire has been fractured afford it access, and 

 as the young brood can make their way through the 

 interstices of the protecting wires and then grow to a 

 dangerous size within the protecting covering. To 

 obviate this danger brother William had constructed 

 a special cable for shallow water, in which strands 

 of the best hemp twisted round the conductors, insu- 

 lated by gutta-percha or caoutchouc, gave the cable 

 the necessary support, whilst a layer of strips of 

 copper - sheathing placed over one another in the 

 manner of scales was destined to protect the core of 

 the cable from the wood -worm. Our London firm, 

 which meanwhile had set up a good-sized mechanical 

 workshop and a cable factory of its own at Charlton 

 near Woolwich, received an order for such a cable 

 from the French government for a line between Car- 

 tagena and Oran. The then director-general of the 

 French telegraphs, M. de Vougie, had already expended 

 much money in attempts to lay a cable from the French 

 to the Algerian coast, without having obtained a satis- 

 factory telegraphic communication. He now wished to 



