Chapter Four 
ENGINEERING DIFFICULTIES 
Most OF THE technical work affecting the cable was done in 
England, where it was made. The question of how large the 
cable should be, and how it should be designed, was a critical 
one. In the limited experience of the British engineers with 
short submarine lines, too light a cable had been carried away 
by the tide, and too heavy a cable had been found difficult to 
unwind from its drum and to pay out over the side of a ship. 
The aim was to get flexibility and strength combined. A 
thick insulation was necessary to prevent the electrical im- 
pulse from being dissipated in the water, whereas a land tele- 
graph line requires only glass supports to insulate it. 
The short cable laid in 1856 between Newfoundland and 
Nova Scotia was the first to be composed of several small cop- 
per wires, instead of a single larger wire. This design was 
flexible and insured that a flaw in a single wire would not 
stop the operation of the cable. For the insulation, there was 
fortunately available from Asia a new vegetable gum called 
gutta-percha and believed superior to rubber. 
It was known, however, that a gutta-percha covering tended 
to absorb some of the electricity flowing through the copper 
wires. Experiments had been made to overcome this static 
loss (which was due to induction) by a series of opposite cur- 
rents or waves of electricity. The Bright brothers and Pro- 
fessor ‘Thomson had worked on this problem. The matter 
was obviously not a simple one. 
As for the size of the cable, Professor Morse reported that 
large coated wires beneath the water or the earth are worse 
conductors than small ones. The great Faraday had stated 
that the larger the wire, the more electricity is required, and 
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