IMPROVEMENTS IN THE CONSTRUCTION OF ELECTRIC TELEGRAPH CABLES AND LINES, AND IN THE MODE OF AND APPARATUS FOR OR CONNECTED WITH THE TRANS- MISSION OF ELECTRIC CURRENTS
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Thomas Walker at the Office
of the Commissioners of Patents, with his Petition, on the 11th
March 1868.
I, THOMAS WALKER, of Robert Street, Chelsea, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF ELECTRIC TELEGRAPH CABLES AND
LINES, AND IN THE MODE OF AND APPARATUS FOR OR CONNECTED WITH THE TRANS-
MISSION OF ELECTRIC CURRENTS," to be as follows, that is to say:-
My improvements in the construction of electric telegraph cables
and lines consist in making them of naked or uninsulated conductors
consisting either of a single wire or tape, or of a bundle, or twisted
helically into a strand or in any other shape to form one conductor,
such conductor to be connected by means of any suitable apparatus
with the positive, negative, or neutral earth plates (by earth plate I
mean any form of connection with the earth) or batteries as may be
required for the transmission or reception of signals. When more than
one uninsulated conductor is required for a cable they must be kept
separate by covering them with any suitable porous material.
For carrying land lines from one distant point to another instead
of the present aerial lines, I lay the naked conductors in the earth,

page_text: keeping them sufficiently apart to prevent confusion. When it is not
convenient to put them in the earth they are suspended in the usual
way without the expense and trouble of insulators. I use the different
earth plates and batteries or earth plates alone in connection with
the lines as herein-before described. Where insulation of the con-
ductors is required for the purpose of separating them or to prevent
oxidation, I use the earth plates and batteries as herein-before described.
When but little power is required I use the earth plates only; for
greater power both earth plates and batteries are used. The conductors
can be covered with any suitable material to obtain strength or weight.
I also use for covering them when necessary dirty or used cotton
engine waste properly prepared for the purpose, which is afterwards
saturated with bituminous, resinous, or other suitable substance when
necessary. This cotton waste also can be used as thread, string, or
cord for other purposes.
My improvements in the mode of transmitting electric currents
through insulated cables and lines, consist in the employment of earth
plates and batteries of several different (at least not less than two)
electrical elements at each end for the purpose of acting positively,
negatively, or neutrally to each other as may be required for trans-
mitting or receiving signals, each battery or earth plate is brought
into contact with the line by the usual or other suitable apparatus.
For cables in use I substitute two or more earth plates at each end
composed of different electrical elements, brought into contact with
the line or batteries as required for receiving or sending signals.
One of my improvements in transmitting apparatus consists in making
a portable battery as air-tight as possible. When the battery is used
with fluids which generate gases, I use a valve opening outwards which
allows the gases to escape and closes again, thereby preventing the
evaporation of the fluids; some substances, such as alkalies, may be used
without a valve. I also use acids, alkalies, or other exciting agents,
mixed with any suitable substance to thicken them or give them body.
The gases may be conveyed away by pipes to avoid the noxious fumes.
Another improvement in the apparatus consists in using a galvan-
ometer coil and needle as a relay. If a horizontal galvanometer be used,
a piece of metal connected with one of the poles of the battery or
earth may be made to touch the axis of the needle, and an arm pro-
jecting from the same is made to touch a a projection connected with

page_text: the battery or earth. If a vertical galvanometer be used, the metal in
which the axis works is connected with the battery or earth, and the
arm of the axis made to touch a stud connected with the battery
or earth. When a current is sent through, the contact is made or
broken as required. I form a transmitting key by using a lever or
spring passing over metallic surfaces connected with the line and
battery or earth plates.
Another improvement in the apparatus consists in making resistance
coils for testing or other purposes, by twisting the fine conductors
helically around any suitable body, instead of bobbins with wires
wrapped over each other as at present used, I thereby avoid the
induction which occurs in the use of bobbins. A number of the
helices may be combined according to the amount of resistance
required.