TRANSACTIONS OF THE SECTIONS. 



179 



sion of not more than one-half its ultimate powers of resistance, would injure the 

 insulation, and what is more than probable, would ultimately destroy the conducti- 

 vity of the cable. These are difficulties which in this weight of cable and large 

 diameter of coils in the tanks has been overcome. With a smaller cable (carefully 

 insulated) depending entirely upon the conducting wires for its strength, it would 

 be possible to wind it in lengths of 80 to 100 miles upon reels, and these, neatly 

 balanced in the hold of the ship, might be paid into the sea entirely free from 

 kinks ; but in doing this it must be observed that considerable risk is incurred of 

 breaking the cable from the amount of friction to which the wheels would be sub- 

 ject when loaded with 80 miles of cable. Taking the whole conditions of these 

 arrangements into account, it is not clear that the reels would be any improvement 

 upon the large coils in tanks, as adopted in the ' Great Eastern' ship. In fact 

 there is no other plan suitable for the paying out of the Atlantic cable of its pre- 

 sent weight and dimensions but the coil. 



With regard to the ' Great Eastern ' ship, he stated that she proved herself 

 everything that could be wished for. Her easy steady motion was just what was 

 required for paying out the cable, and its relief from undue strain by the absence 

 of pitching renders the ship exclusively calculated for the submergence of subma- 

 rine cables in deep water. She is the very thing that is wanted for such a pur- 

 pose, and he firmly believed, if she was properly fitted and prepared for such a ser- 

 vice — with some additional stringers to strengthen the upper deck and sides — she 

 would find full employment as a sub merger of cables in every sea which divides 

 the four quarters of the globe. She is admirably adapted fer such a purpose, and 

 her double engines, with screw and paddles, assist the steering, and afford great 

 facilities for paying out and hauling' in the cable shoidd accidents occur such as 

 overtook the vessel in the middle of the Atlantic. 



The author further remarked that the recovery of a lost cable is at all times a 

 precarious operation, and the difficulties which present themselves in the case of the 

 Atlantic cable, are its large diameter and the friction of its external surface in pas- 

 sing through the water. If raised at all it must be at an exceedingly slow speed, 

 and that with one end loose, otherwise he shoidd despair of raising it froni a depth 

 of 2100 fathoms, by hooking it in the bight or middle, where the resistance would 

 be doubled in raising two sides instead of one. 



Supposing the cable to be hooked by the grapnel at a few miles distant from the 

 fracture, it will then be seen (if it is to be raised from a depth of 2 J miles) that 

 the present cable would have to be lifted at an angle of about 45° on each side, or 

 3-18 miles of cable =6-25 x 11 cwt. (the weight of the cable in water), a weight of 

 4J tons, or equivalent to more than one-half the breaking strain. To this dead 

 weight must be added the friction of the two sides of the triangle AB and AC, 



which will be as the squares of the velocities with which it is raised. What may 

 be the additional amount of strain from the speed with which it may be drawn 

 through the water it is not necessaiy here to calculate, as it is obvious that at a 



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