496 
Proceedings of the Royal Society 
one side, and Trinity Bay, Newfoundland, on the other, regarded 
merely as a mechanical achievement, took by surprise some of the 
most celebrated engineers of the day, who had not concealed their 
opinion, that the Atlantic Telegraph Company had undertaken an 
impossible problem. As a mechanical achievement it was com- 
pletely successful ; and the electric failure, after several hundred 
messages (comprising upwards of 4359 words) had been transmitted 
between Valencia and Newfoundland, was owing to electric faults 
existing in the cable before it went to sea. Such faults cannot 
escape detection, in the course of the manufacture, under the 
improved electric testing since brought into practice, and the causes 
which led to the failure of the first Atlantic cable no longer exist 
as dangers in submarine telegraphic enterprise. But the possibility 
of damage being done to the insulation of the electric conductor 
before it leaves the ship (illustrated by the occurrences 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 1200 
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. 
Forces concerned in the Submergence of a Cable. 
In a paper published in the ‘^Engineer” Journal in 1857, the 
speaker had given the differential equations of the catenary formed 
by a submarine cable between the ship and the bottom, during the 
submergence, under the influence of gravity and fluid friction and 
pressure ; and he had pointed out that the curve becomes a straight 
line in the case of no tension at the bottom. As this is always the 
