Pe pine 
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12 The Atlantic Cable. 
three Atlantic cables is a fair illustration of the progress 
made in the manufacture of deep sea cables. 
1858. 
Conductor—-A copper strand, consisting of seven wires 
(six laid round one), and weighing 107 lbs. per nautical 
mile. 
Insulator—Gutta percha laid on in three coverings, and 
weighing 261 lbs. per knot. 
External protection—Eighteen strands of charcoal iron 
wire, each strand composed of seven wires (six laid round 
one), laid spirally round the core, which latter was pre- 
viously padded with a serving of hemp saturated with a 
tar mixture. The separate wires were each 224 gauge, the 
strand complete was No. 14 gauge. 
Weight in air—z2o cwt. per nautical mile. 
Weight in water—13'4 cwt. per nautical mile. 
Breaking strain—3 tons 5 cwt., or equal to 4°85 times its 
weight in water per nautical mile; that is to say, the cable 
would bear its own weight in a ieee less than five miles 
depth of water. 
Deepest water to be peartcued! 2,400 fathoms, or less 
than 24 nautical miles. 
ave Behe strain was equal to 4°85 times its weight 
per nautical mile in water. 
Length of cable shipped—2,174 nautical miles. 
1865. 
Conductor—Copper strand consisting of seven wires (six 
laid round one), and weighing 300 lbs. per nautical mile, 
embedded for solidity in Chatterton’s compound. Gauge 
of single wire ‘048 = ordinary 18 gauge. Gauge of strand 
‘144 = ordinary No. I0 gauge. 
Insulation—Gutta percha, four layers of which are laid 
on alternately with four thin layers of Chatterton’s com- 
pound. The weight of the entire insulation 400 lbs per 
nautical mile. Diameter of core ‘464, circumference of 
core 1°392. 
External protection+Ten solid wires of the gauge 095 
