The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

CAUSE OF THE FAILURE OF THE CABLE. 647
fault was enlarged very slowly to one tenth of an inch. On
repetition with the coils, the fault was increased to one tenth
diameter, and with the batteries to one sixth, rapidly with both.
No further burning can take place with either current till the
wire is brought to the surface of the water, when, owing to the
resistance increasing, by the fault being only partly immersed,
the burning commences anew and the gutta-percha inflames.
On the arrival of my large magnetic machine, I put it
together, and connected it with the cable, and have used it a
part of every day since, sending at some times reversals and
at others words and sentences. I am unable to tell whether
-hey were received and understood, but hope to find such has
been the case on the receipt of intelligence from Newfoundland.
Having a machine at one end only, it will, of course, be evident
that, even if they received properly, they could not have
answered better than before. But we have been encouraged
by seeing more reversals and attempts to send words from them
lately than before. I will leave the machine here; it will be
worked at stated hours each day by the assistants until the
days fixed upon in October, when it will be used alternately as arranged with the battery and coils. The clerks at
each end will then act according to preconcerted arrangements,
which I hope will have the effect of renewing telegraphic correspondence. If that is not accomplished, probably the best thing
then would be to raise the cable for about 15 miles out and test.
I cannot say I have any hopes of the fault being found within
that distance, but as it would not be attended with any trouble
or risk I think it worth the trial. If the injury is in the deep
soundings, I believe any attempt to raise it would be the means
of breaking the cable and losing the end altogether. If the
state of the cable should not get worse I am still in hopes of
its being rendered workable by transmitting signals slowly, by
having delicate receiving apparatus, and by adopting means for
neutralizing the earth current. Professor Thomson has partially succeeded in the latter object by throwing ifito the receiving end of the line feeble currents of different values, from one
cell to one twentieth of a cell, in opposition to the earth current.
I am, gentlemen, yours obediently,
W. T. HENLEY, Telegraph Engineer.
46 John-street-road, Clerkenwell.
Various trials have been made to work the cable since the
report of Mr. Henley was submitted, but without success. The
company has exerted itself to make available the great enterprise, but thus far, sadly to be recorded, in vain.