.s7A- \\-lLUAM SIEMENS, /-.A'..V. 113 



Supposing the iron wire to be corroded away iu a place of partial 

 support, then the cable to the right and left of that place would 

 naturally sink. Thus readjustment of the weight of the cable 

 upon the bottom naturally took place at the expense of the part 

 where the strength had gone, causing the insulated conductor to 

 elongate and to break. He thought, therefore, the outer sheathing 

 ouirht to be permanent, in order that the cable itself might be so. 

 He 1 1 ad advocated for years a particular form of cable, made of hemp 

 laid longitudinally, and covered with a flexible armour of sheet 

 copper. He had laid about 200 miles of that cable in different 

 parts of the world, and he found it to be very permanent, where it 

 was not broken by mechanical agencies. The specimen exhibited 

 had been taken from a depth of 1,500 fathoms, after being a year 

 submerged. It was quite intact, whereas the iron-covered shore 

 end was much corroded. He mentioned that fact in answer to 

 what had been observed as to the impossibility of picking up a 

 cable from a great depth. 



Mr. Longridgc said his remark applied principally to the 

 Atlantic cable. If the end could be recovered, the cable could be 

 under-run ; but with the end lost, to pick it up and raise it to the 

 surface from a depth of 2,000 fathoms, he believed, was impossible. 



Mr. Siemens agreed in that case with Mr. Longridge. Prac- 

 tically it was of the utmost importance that the cable should be 

 smooth, so as to be suitable for being picked up, or under-run. 

 A cable covered with hemp could only be got up at a slow rate, 

 but a smooth cable would come up with very little resistance. 

 With regard to the lines in India, it had been said that iron posts 

 did not answer so well as wooden ones. He differed from that 

 opinion, as he had put up above a thousand miles of land telegraph 

 upon iron posts, with most satisfactory results. Of course better 

 insulation was required with iron than with wood ; and one of the 

 great faults of insulators was, that they were generally put upon 

 brackets, and the wire was either suspended on the top or by the 

 side of them. That was an imperfect form of insulator, inasmuch 

 as on a heavy rain falling upon the bracket, the spray rose into 

 the cup and destroyed insulation during the rain. All wires 

 should be suspended from the insulating cup, a system which he 

 had followed for many years, in constructing his bell insulator with 

 vulcanite stalk. With a properly insulated line, with a proper 



VOL. II. I 



