IMPROVEMENTS IN MANUFACTURING AND LAYING DOWN SUBMARINE TELEGRAPHIC CABLES
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Theophilus Berrens at the
Office of the Commissioners of Patents, with his Petition, on the
11th December 1865.
I, THEOPHILUS BERRENS, of the Town of Tarbes, now No. 60, Boule-
vart de Strasbourg, Paris, in the Empire of France, Railway Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
MANUFACTURING AND LAYING DOWN SUBMARINE TELEGRAPHIC CABLES," to be as
follows:-
The submarine telegraphic cables made in accordance with the present
Invention have several separate copper wire conductors which are laid
or arranged round a central core, consisting of three or more steel wires.
I prefer the number of five conductors as that most convenient for the
construction of submarine cables according to the present Invention, each
of these conductors being composed of three separate copper wires lightly
twisted together. The three or four steel wires that form the core, being
previously coated over with Chatterton composition, are tightly bound
together with hemp; the whole is then coated over with insulating layers
of gutta percha and Chatterton composition alternately to the thickness of
about five-sixteenths of an inch. The three twisted copper wires of each
conductor are bound together with thread or fine yarn impregnated with
an elastic and drying composition consisting of tar, rosin, bees-wax, and
tallow; the conductors are then coated over alternately with Chatterton

page_text: insulating composition and gutta percha to the thickness of about two-fifths
of an inch. When thus prepared the conductors are laid or arranged
round the central steel core, and the external interstices formed by the
junction are filled up with strands of hemp or other suitable material;
the whole is then bound together or served with hemp impregnated
with waterproof and non-conducting material, and afterwards bound spi-
rally with strands of hemp impregnated with a preserving composition.
The cable thus completed is rolled between two rollers so as to give it a
uniform diameter of about 1-4 inch; and greater compactness and strength
is given to it by means of rounds of iron or copper tinned wire, with
which it may be bound together from place to place. In this state the
telegraphic cable is fit to be submerged in depths not exceeding, say, five
thousand feet.
For the purpose of laying or submerging the cable it is uncoiled from
the ship's hold and carried over a pulley placed at the stern, and then
over another pulley upon a floating pontoon which is towed by the ship
at a suitable distance behind her.
I prepare submarine cables intended for depths exceeding five thousand
feet in a similar manner to those previously described, but the core must
be composed of a greater number of steel wires, or of steel wires of a larger
diameter, so as to resist the increased strain incident to the additional
pressure due to the greater depth of the water; while the conductors are
to consist of either three or four twisted copper wires or strips, a greater
strength and compactness being given to the whole cable. The latter is
coated over with insulating layers similar to those of the cable previously
described; it is then bound with strands of hemp impregnated with a
bituminous and greasy composition, and bound at various parts of its
length with tinned wire; but I prefer not to employ the spiral iron wire
jacket which I proposed for the cable previously described.
For the purpose of laying or submerging the latter cable I employ the
same means as before described, but with a view to obviate undue strain
on the cable while passing over the ship's stern I propose that floats made
of thin sheets of copper and filled with sulphuric ether be attached to the
cable at distances of about one mile, and I so attach these floats to the
cable as to allow them to be disengaged when they reach a distance of
about one hundred and fifty yards from the bottom of the sea. This I
operate by means of a kind of winch attached to the bottom of each float
àt its outer surface, and the drum of which is wound up previous to the
submersion of the float. To the latter the cable is attached by means of

page_text: a key connected with the winch. A balance weight is suspended to the
winch by means of a rope and prevents the connection from unwinding;
but as soon as the balance weight comes in contact with the bottom of the
sea, when the float and cable have been discharged free of the ship and
pontoon and allowed to sink, the winch will be set free by means of a
detent and so release the float from the cable. The float being thus
disengaged from the cable will ascend to the surface, where the floats may
be collected and returned on board the ship.