IMPROVEMENTS IN TELEGRAPHIC CABLES
Year: 1869

page_text: LETTERS PATENT to Alfred Foucaut, of Orleans, France, Medical
Doctor, for the invention of "IMPROVEMENTS IN TELEGRAPHIC CABLES."
PROVISIONAL SPECIFICATION left by the said Alfred Foucaut at the
Office of the Commissioners of Patents, with his Petition, on the
2nd July 1869.
1, ALFRED FOUCAUT, of Orleans, France, Medical Doctor, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN TELEGRAPHIC
CABLES," to be as follows:-
In making a cable of one or more conductors I use as conductors
single copper or other metallic wires, or I twist several smaller wires
together to form one conductor of the proper size. 1 cover each con-
ductor with a coating of gutta percha or other insulating material, such
as a compound of parafine, and I wrap a cotton thread on to completely
cover the gutta percha; or instead of the gutta percha L'employ a com-"
position of cuiuse or carbonate of lead, finely powdered, and mixed with
[Price]

page_text: litharged oil and sawdust to the proper consistency; I then cover the
gutta percha or composition already described with a metallic conducting
coating. I use preferably a coating of plumbago applied by friction, or
a coating of tinfoil; or I wrap a small copper or other metallic wire in
long spirals around the gutta percha or composition. Any conductor
properly applied will answer the same purpose. This metallic surface
or wire is connected with the ground at each end of the cable, or at any
other point or points that may be required to carry off or properly
employ and control all induced currents of electricity. I then saturate
a linen band with a mastic composed of ceruse or carbonate of lead,
finely powdered, and mixed with litharged oil and paraffine to a proper
consistency, and I wrap the linen band so prepared around each con-
ductor already covered, as above described, cach turn of the band lapping
over the previous turn. The different conductors are then brought to-
gether and wrapped with the same band, and over all is wrapped a tarred
rope of the thickness desired, which is covered with a coating of coal
tar, and over this is wrapped a linen band tarred as usual. Cables for
submarine use may be afterwards armoured as usual with iron wires of a
size suitable to the locality and the work which they have to perform.
I am aware that a metallic coating consisting of a metallic strip wound
around the insulating material is not new, but the said metallic strip has
been used as a conductor of the main current; this differs from my
Invention in that my metallic coating acts as a conductor for the induced
current alone, or is intended to be used when several conductors are
grouped together. It is also an important feature of my Invention that
the conductor should be placed in connexion with the earth, my method
of applying the metallic coating is believed to totally destroy the effects
of induction, and is of great efficiency in increasing the transmitting
power in submarine cables.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 3
filed by the said Alfred Foucaut in the Great Seal Patent Office
on the 1st January 1870.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of July, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors.
give and grant unto me, the said Alfred Foucaut, Her special licence
that I, the said Alfred Foucaut, my executors, administrators, and
assigns, or such others as I, the said Alfred Foucaut, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for IMPROVEMENTS
IN TELEGRAPHIC CABLES." upon the condition (amongst others) that I, the
said Alfred Foucaut, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I. the said Alfred Foucaut. do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the Drawings
hereunto annexed, that is to say:-
In making a cable of one or more conductors I use as conductors
single copper or other metallic wires, or I twist several smaller wires
together to form one conductor of the proper size. I cover each
conductor with a coating of gutta percha or other insulating material,
and I wrap a cotton thread upon it so as to completely cover the gutta
percha, or I form a composition of ceruse or carbonate of lead finely
powdered and mixed with litharge oil and sawdust to the proper con:
sistency, which is to be applied in the same manner and in lieu of the
gutta perch I then cover the gutta percha or the composition and
cotton threads with a metallic conducting coating. I use preferably a
coating of plumbago applied by friction, or a coating of tin or other metal
foil; or I wrap a small metallic wire in long spirals around the gutta

page_text: percha or composition and cotton. Any other kind of conductor if pro-
perly applied will answer the same purpose. This metallic surface or
wire is connected, if necessary, with the earth at each end of the cable,
or at any other point or points that may be desired to carry off or
properly employ and control all earth or induced currents of electricity.
I then saturate a linen band with a mastic composed of ceruse or car-
bonate of lead finely powdered and brought to a proper consistency by
mixing litharge oil therewith, and I wrap the linen band so prepared
around the conductor or conductors already covered as above described,
each turn of the band lapping over the previous turn. Several con-
ductors are then brought together to form a cable, and wrapped with a
band, over which a tarred rope or cord of the thickness desired is "served"
or wrapped. The rope or cord is covered with a coating of coal tar or
other preserving agent, and to protect this I wrap a linen band which
is tarred as usual or painted over with a solution of caoutchouc (in-
dianite). Cables for submarine use may be afterwards armoured as usua!
with wires of a size suitable to the locality and the work which they have
to perform.
In order to make a cable of great resisting power I replace each of the
copper conductors with a steel wire, which is isolated like the copper
wire in order to protect its magnetization from the influence of currents.
In the formation of these cables I attach great importance, 1st, to the
interposition between the several conductors of a metallic partition for
collecting the earth or induction current or currents and constituting the
best means of isolation; and, secondly, the employment of the ceruse as
possessing the property of hardening during its immersion in water; the
covering of ceruse therefore protects the gutta percha more and more
from the action of the air and water, and it thus follows that the older
the cable the better the copper or conducting wire is enclosed.
The Drawing hereunto annexed shows at Figure 1 a portion of my cable
at different stages of its manufacture; Figure 2 shows, by way of example,
a transverse section of a cable composed of seven conductors.
Each con-
ductor a is composed of one, two, three, four, or a greater number of
wires of copper either spun or interlaced to form a stout body. Each
conducting wire is surrounded with gutta percha b, and upon the latter is
rolled an envelope of cotton thread or fibre c impregnated or coated with

page_text: ceruse. It is above this cerused cotton that a sheet of thin tin d or other
metal foil is applied, cut into bandelets of about one-third of an inch in
breadth, which are rolled or wrapped into spirals either by the hand or
mechanically upon each conducting wire. The conductors thus prepared
are then united into a sheaf or cable corc, and this sheaf or cable core
may be covered with ceruse, gutta percha, or other isolating material or
compound capable of hardening, and which will fill all interstices. I then
take a strip of linen e saturated with a mastic of ceruse, and I envelope
the sheaf or cable core with this band. The whole is then served with a
tarred rope or cord g, and then finally covered with a tarred cloth h.
In this system the metallic partitions form distinct compartments (see
Figure 2) and completely isolate each of the conductors a. The ceruse,
ceruse mastic or other compound is enclosed within the metallic par-
titions d, and there solidifies in the form of a sort of trapezium.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,-
Firstly. The general construction of a telegraphic cable, substantially
in the manner described.
Secondly. A conducting surface for induction currents and insulation
when applied to the outside of the insulating coating of each group
of conductors or of one conductor, in the manner and for the purpose
described.
Thirdly. The employment of a band saturated with a mixture or
compound of ceruse, or carbonate of lead, and litharge, or other oils
when arranged in telegraphic cables, in the manner and for the purpose
herein described.
Fourthly. In telegraphic cables the construction of the coatings
formed of gutta percha or compositions, the metallic conducting surface,
the cotton thread, the band saturated with mastic of carbonate of lead or
ceruse, and the tarred rope, arranged in the manner and for the purpose
described.
Fifthly. I claim as an insulating material used in the construction of
telegraphic cables the composition composed of carbonate of lead or
ceruse or other similar hardening substance, litharge or other oil, sawdust,

page_text: purpose described.
In witness whereof, I, the said Alfred Foucaut, have hereunto set
my hand and seal, the Eighteenth day of December, in the year
of our Lord One thousand eight hundred and sixty-nine.
Witness,
CH. ARMENGAUD,
ALFRED FOUCAUT. (L.S.)
Civil Engineer,
23, Boulevard de Strasbourg,
à Paris.