122 



Submarine Telegraphy. 



as consisting of ooze, is known to be rocky and rough to an 

 extent that wonld justify considerable fears for the continued 

 integrity of any cable lying across it. 



In order to appreciate the precantions taken with the last 

 cable with a view to guard against a failure similar to that of 

 1858,, a comparison of the two cables may here be made. A 

 longitudinal and sectional view of each is given in Figs. 4 and 

 5. A glance at these diagrams, which are drawn of the same 



OLD ATLANTIC CABLE, 1858. 



Tie. 4. 



NEW ATLANTIC CABLE, 1865. 



Fig. 5. 



diameter as the cables themselves, will at once inform the 

 reader of their respective sizes. The diagram A in each figure 

 is the sectional view, and B a longitudinal. The conductor in 

 each consists of seven wires (six laid round one), but in the 

 cable of 1858 this copper strand weighed 107 lbs. per mile, 

 while that of 1865 weighed 300 lbs., which was embedded for 

 the sake of solidity, and not with a view of insulating the wires 

 from each other, in a matrix of Chatterton's compound. These 

 conducting wires were insulated in the former case by gutta. 

 percha, laid on in three coverings, and weighing 261 lbs. per 

 mile; in the latter . by four coverings laid on alternately with 

 thin layers of Chatterton's compound, making a weight of 

 400 lbs. per mile, and bringing up the core to a diameter of 

 nearly half (*464) an inch. For the protection of this essential 

 part the cable of 1858 was surrounded by eighteen strands of 

 iron wire, each strand consisting of seven wires (six round one), 

 laid spirally round the core, the latter having been previously 



