424 POPULAR LECTURES AND ADDRESSES. 



enterprise. But the possibility of damage being- 

 done to the insulation of the electric conductor 

 before it leaves the ship (illustrated by the occur- 

 rences which led to the temporary loss of the 1865 

 cable), implies a danger which can only be 

 thoroughly guarded against by being ready at any 

 moment to back the ship and check the egress of 

 the cable, and to hold on for some time, or to haul 

 back some length according to the results of 

 electric testing. 



The forces concerned in these operations, and the 

 mechanical arrangements by which they are 

 applied and directed, constitute one chief part of 

 the present address ; the remainder is devoted to 

 explanations as to the problem of lifting the west 

 end of the 1,200 miles of cable laid last summer, 

 from Valencia westwards, and now lying in perfect 

 electric condition (in the very safest place in which 

 a submarine cable can be kept), and ready to do its 

 work, as soon as it is connected with Newfoundland, 

 by the 600 miles required to complete the line. 



