Submarine cable laying and repairing

264 SUBBIAEIXE CABLE LAYING AND REPAIRING.
tools, spare jointing materials, galvanometer mirrors and suspensions,
&c. {see Fig. 155). The batteries, •which may amount
to two or three hundred cells, are all ranged in racks underneath
the testing-table, and the connections brought to commutatora
by which the battery power can be easily changed as required.
There is also a library, and a comfortable lounge along one
side of the room, this sanctum of the electrician being
generally a cosy little place, where are spent some of the
many hours passed at sea while steaming from one position to
another. In bad weather it is a welcome retreat, from whence
you can, reclining,
" With sidelong eye look out upon the scene,"
though it may be in no such satisfied frame of mind as "Wordsworth's
dreaming man.
It will be understood that on starting the coiling of cable
picked up, the end was left sticking up at the side of the tank,
so as to be accessible for connecting on an insulated leading
wire to the testing-room. This insulated wire remains so con-
nected until the first cut takes place, when it is shifted on to
the new end. In the testing-room the end of this wire is con-,
nected to the testing terminal during the ship's tests, or is^
shifted over to a terminal on the speaking connections when it
is desired to communicate with the shore. Also in the periods
of time during which it is arranged for the shore to test, the
end is either freed or earthed by the ship as required.
A set of testing and speaking connections, such as fitted in
the testing-room of a repairing steamer, is shown in Fig. 156.
The apparatus and arrangement of connections vary somewhat
in difierent ships, but are generally arranged in such a manner
that by simply changing one or two plugs the cable can be tested
by bridge or deflection methods. The galvanometers used are
either the marine astatic galvanometer of Lord Kelvin, with
the damping device, or the Sullivan suspended coil galvanometer.
In the set of connections here shown, the cable is connected to
the terminal S for speaking to the shore, and to the terminal X
for testing, the commutator plugs P P and the plug B being put
in for bridge test, and the plug D being put in (the others being
removed) for deflection test. In addition to the instruments
shown, there are high resistances and standard cell for the