IMPROVE- MENTS IN ELECTRIC TELEGRAPHS
Year: 1860

page_text: LETTERS PATENT to Charles Weightman Harrison, of Plumstead Common,
in the County of Kent, Civil Engineer, for the Invention of "IMPROVE-
MENTS IN ELECTRIC TELEGRAPHS."
PROVISIONAL SPECIFICATION left by the said Charles Weightman
Harrison at the Office of the Commissioners of Patents, with his
Petition, on the 1st September 1860.
I, CHARLES WEIGHTMAN HARRISON, of Plumstead Common, in the County
of Kent, Civil Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN ELECTRIC TELEGRAPHS," to be as follows:-
My Invention relates to certain improved modes of constructing electric
telegraph lines, especially when intended for submarine and subteranean
communication.
The first of my improvements herein affords a means for transmitting signals
through lines of great length, and with a certainty and rapidity which has not
heretofore been attained. I effect this object by forming the line in sections
or parts, each section being made to act as a complete circuit in itself; and I
place an inductive helix or apparatus of any suitable construction in every
section, for the purpose of generating under the influence of a passing current
another or secondary current, which, by a proper connection, is conducted
onward, to operate. through an adjoining section of the line. In this manner
[Price 8d.]

page_text: any number of sections and helices may be adapted to make up an entire line,
the current in one section being developed under the influence of the current
in another section, and so on throughout the series. I prefer to inclose the
inductive apparatus in a case of metal, which may be made to form the
terminal earth plate of its circuit. By this arrangement much of the adverse
action of natural currents is avoided, as well as that of the residual or Leyden
jar charge of a continuous long line.
The second part of my Invention relates to a mode of dissipating the
residual or Leyden jar charge which attends the use of insulated submarine
electric conductors. It is well known that the pointed form of bodies
determines an electric charge or reaction much more than the rest of the
surface; and that whatever may be the amount of electricity induced, it
always tends to escape at the points. This ready effect of points is a con-
sequence of the distribution of electricity, which, by the convergence of the
lines of inductive force becomes more intense towards a point or edge. Now,
this part of my Invention has this elementary principle for its base, and
consists in giving improved forms of construction to the conductor and
insulating or protecting medium by forming edges, angles, or points in or
upon them, or any of them, in place of making them smooth and round as
hitherto done.
The third part of my Invention consists in a means of preventing the decay
of the outer or protecting wires of electric cables by surrounding them with
fibrous material saturated with a compound of india-rubber or gutta percha,
or similar gum.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Weightman Harrison in the Great Seal Patent
Office on the 1st March 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
WEIGHTMAN HARRISON, of Plumstead Common, in the County of Kent,
Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of September, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Charles Weightman Harrison, Her special licence that I, the said Charles
Weightman Harrison, my executors, administrators, and assigns, or such others

page_text: as I, the said Charles Weightman Harrison, 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 ELECTRIC TELEGRAPHS," upon the condition (amongst others)
that I, the said Charles Weightman Harrison, 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 Charles Weightman Harrison, 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:-
My Invention relates to improved modes of constructing electric telegraph
lines, especially when intended for submarine and subterranean communication.
The first of my improvements herein affords a means for transmitting signals
through lines of great length, and with a certainty and rapidity which has not
heretofore been attained. I effect this object by forming the line in sections
or parts, each section being made to act as a complete circuit in itself; and I
place in every section an inductive helix or apparatus of any suitable con-
struction for the purpose of generating, under the influence of a passing
current, another or secondary current, which by a proper connection is con-
ducted onward to operate through an adjoining section of the line. In this
manner any number of sections and helices may be adapted to make up an
entire line, the current in one section being developed under the influence of
the current in another section, and so on throughout the series. I prefer to
inclose the inductive apparatus in a case of metal, which may be made to form.
the terminal earth plate of its circuit. By this arrangement much of the
adverse action of natural currents is avoided, as well as that of the residual or
Leyden jar charge of a continuous long line.
The second part of my Invention relates to a mode of dissipating the residual.
or Leyden jar charge which attends the use of insulated submarine electric
conductors. It is well known that the pointed form of bodies determines an
electric charge or reaction much more than the rest of the surface, and that
whatever be the amount of electricity induced, it always tends to escape at

page_text: the points. This ready effect of points is a consequence of the distribution of
electricity, which by the convergence of the lines of inductive force becomes
more intense towards a point or edge. Now, this part of my Invention has
this elementary principle for its base, and consists in giving improved forms
of construction to the conductor, and insulating or protecting medium, by
forming edges, angles, or points in or upon them or any of them, in place of
making them smooth and round, as hitherto done.
The third part of my Invention consists in a means of preventing the decay
of the outer or protecting wires of electric cables, by surrounding them with
fibrous material saturated with a compound of india-rubber or gutta percha or
similar gum.
I will now proceed to describe more particularly the several parts of this
telegraphic system.
Figure 1 is a plan of an electric telegraph line connecting the stations A
and B; but instead of forming this in one continuous circuit, as hitherto done,
I divide it into two circuits, the currents generated at A or B going to earth
at C, after having induced a secondary current, which flows through the
onward circuit, and passes to earth at A or B, according to the direction
given. In this arrangement it will be observed there are four points of
discharge to earth, instead of only two as in the ordinary plan; the line will
therefore be cleared of the residual or Leyden jar charge in half the time
occupied by a single line of equal length, thereby permitting double the
number of messages to be sent through it. The sectional line may also be
worked with greater safety than the ordinary continuous line, because there
is no necessity to force the intensity of the current beyond the sectional
resistance. For instance, an ordinary line which would require 40° of
intensity to work it, is capable of being worked on the sectional principle by
currents of 20° or 10° if divided into two or four sections, hence the liability
to injury from this source would be reduced to one-half in the first case, and
to one-fourth in the other. The conflicting influence, too, produced in ordinary
submarine lines by natural or earth currents, is reduced one-half by adopting
the sectional system, and connecting the batteries so that they shall deliver
plus and minus currents alternately.
The inductive apparatus or battery which I have found most suitable to use,
not only in the sectional system, but in telegraph lines generally, producing
the highest effect, is illustrated in Figures 2 (longitudinal section) and
3 (cross section), wherein a series of primary and secondary helices with the
soft iron cores (a) are placed around each other concentrically, so as to bring
a large amount of surface of these different elements in close proximity.

page_text: For convenience of arrangement when my Invention is intended to be used
in submarine lines, I place two inductive batteries near together in one outer
case, as shown in Figure 2, and to insulate them I surround each with a
thick coating of gutta percha b, b, the aperture at each end of the case being
securely stopped by a cone of india-rubber c. For the outer case I prefer
to use copper, and to form it in two pieces, which screw together in the
middle; and to prevent the access of water, the two are then well brased
together, and covered at that part with marine glue or other suitable body.
The other outer surface of the case is left uninsulated, so that it may be made
available as an earth plate for the circuits. To facilitate the discharge of the
currents from the case to the earth (or water) I form flutes or edges on the
outside, as shown in Figures 3 and 4.
In the construction of the helices, I prefer to employ a flat ribbon of copper
in place of the ordinary cylindrical wire, as being the most perfect form of
primary conductor, and for the secondary conductor I use a square wire,
thereby in each case avoiding any loss of power from vacancies. By alterations
in the length and sectional areas of these conductors, the inductive current
produced in the secondary helices can be varied to any extent to suit the
nature of the line through which the effects are intended to be propagated.
An intense or quantity current can be obtained from this induction battery as
desired. For intensity of current the conductors of the secondary helices may
be joined, so that the current will run undividedly through them from one end
to the other, the two ends forming the two poles of the battery. If a quantity
current is requisite, the ends of these helices, having a like polarity, are
collected together; the sum of the quantity which is divided between their
number is thus united for producing quantitative effects. The cores are made
of thin soft iron tubes, by which they are able to gain and loose their magnetism
with great facility, and to prevent the establishment of inductive currents
within them, each tube is split down from end to end, as shewn in Figure 7.
In place of tubes, bundles of iron wire may be placed similarly, but I prefer
the former; and in each case to preserve the iron, I coat it with a durable
varnish. A peculiar feature possessed by this induction battery is, that the
whole of the secondary conductor is surrounded by particles through which
the inductive effect is developed, thereby yielding the full extent of duty.
The above-named arrangement of helices and iron cores may be varied with
nearly equal advantages when placed as seen in cross section, Figure 4, thus,
videlicit, iron core, primary helix, secondary helix, iron core, primary helix,
secondary helix, &c., to any number of elements required.
A suitable mode of connection by which the current induced in the secondary.

page_text: helices is conducted onward to an adjoining section of the line, and made to
form the terminal portion of that end of the circuit is shewn in Figure 2, and
separately in the face view, Figure 5; f is a disc of copper or other metal
having an opening cut in the centre of the form shown at g, and a slit made
through to its outer edge to prevent induction. This disc is insulated with a
suitable varnish to prevent metallic contact with the soft iron cores of the
helix upon which it is placed; h is an arm turning on the axis i, and sup-
ported by a bearing fastened on the disc. A forked end on one side of this arm
carries a small plate of soft iron k, which acts as an armature to a part of the
two interior cores in front of which it is placed, and is attracted by them
whenever a current is passing through the primary helices. The other side of
the arm carries a stud 1 of platinum, or other similarly inoxidizable metal,
which through its axis, and the light spring m pressing it against the stud, is
in metallic contact with the outer metal case e, thus forming a path to earth;
a short tube g is then placed upon the disc in the case. To the inside of this
tube a standard of ebonite p or other suitable non-conductor is fixed by the
brackets q, q.
On each side of the top of the standard studs of platinum r, s,
are let in; these studs are each in contact with the primary helices of an
inductive battery, the primary conductor o of the first inductive battery being
joined to the stud s, and the primary conductor from the second battery to the
stud r. Upon this tube another disc f¹, similar to the one already described,
is placed, and then soldered around its edge to the outer case e, one end t of the
secondary helices of the first inductive battery is joined to the outer case e, and
the other end to the line of the second section. In like manner connection is
made with the ends of the secondary helices of the second inductive battery to
the case, and first section of the line.
The operation of this part of the apparatus will be seen to be as follows:-
On the transmission of a current through the first section of the line and
primary helices in connection therewith, the iron keeper k is attracted to the
iron core drawing with it the stud l away from contact with the stud r thereby
breaking the earth path of the primary conductor of the second inductive
battery, and leaving the terminal secondary conductor t, which is joined to the
case e to form the path to earth of the second section of the line, the other end
being joined to the line of the second section as herein described. To secure
the cases of induction batteries to their positions on submarine lines I place
cords or ropes of a fibrous or other material around them, and fasten to the
line; a mode of doing this is shewn at d, in Figures 2, 3, & 4. When my
Invention is used on land lines, the outer case may be dispensed with, and the
conductors carried instead to ordinary earth plates.

page_text: Although I have described this part of my Invention as being peculiarly
suitable to submarine lines, yet it is also applicable with great advantage
to land lines (either suspended or subterranean), in which it is calculated to
supersede the ordinary relay instruments and voltaic batteries. It admits also
of being used with a voltaic battery, conductors from the poles of which may
be brought, by the attraction of the keeper to the cores of the inductive battery
as herein-before described, into contact with the conductor of the primary helix,
the voltaic current passing with and increasing the effect of the line current in
producing induction. Other modes than that which has been detailed of con-
structing inductive batteries, and carrying out this part of my Invention, may
be advised and brought into practice, I therefore desire it to be understood
that I do not confine myself to the precise details or arrangements which I
have described for carrying it out, so long as its main features are observed.
In this respect I will here observe, that in some instances it may not be
necessary to employ a moveable break piece in connection with the
inductive batteries for working telegraph lines; and
local inductive batteries going to or breaking earth at intervals or sections
may be made with advantage to work long lines in aid of the first or primary
current.
again in land lines
In carrying out the second part of my Invention, I give improved forms of
construction to the conductor by employing a strand of any required number
of wires, and then passing the strand as it is being formed (so as to press out
any loops which might otherwise arise) through rollers grooved of a suitable
size, by means of which the wires are pressed close together, and made to form
edges or angles which fill up the space that is lost in using ordinary round
wires. To facilitate the discharge of electricity to earth at the conducting
terminals I form edges or points upon them, as shown at e, in Figures 3 and 4;
I also reduce the surface of the insulating medium, and thereby lessen the
Leyden jar effect by forming its outer surface in angles, as shown in Figure 6,
in place of making it round, as hitherto done, and seen by the dotted line in
the Figure.
The compound of gutta percha or india-rubber, or similar gum, which I
use in carrying out the third part of this my Invention, consists of 1 lb. of
gutta percha or india-rubber dissolved in 4 gallons of tar oil and 24 lbs of
resin dissolved in 12 gallons of bone or Dippel's oil, these are well mixed and
heated together in an iron vessel. The fibrous material, which may be of strips
or strands of hemp or cocoa fibre, is then dipped in the hot liquid until
thoroughly saturated, when it may be wound around each of the outer or
protecting wires previous to their being laid on the cable. The advantage of

page_text: using this compound is, that it remains viscid for some time, and thereby
unites the convolutions of fibrous material into a close and durable covering,
ultimately becoming hard, and preventing decay of the metal from the access
of water.
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 as of my Inven-
tion of "Improvements in Electric Telegraphs,"
First, the construction of electric telegraph lines in two or more parts or
sections, each of which is made to contain an inductive helix or apparatus for
generating a secondary current as herein-before described.
Second, the arrangement of inductive batteries in pairs, by which means
telegraphic signals may be propagated in reverse directions.
Third, the construction of concentric inductive batteries as herein-before
described and represented in the accompanying Drawings.
Fourth, inclosing the inductive apparatus in a case of metal, which may
form the whole or a portion of a terminal or earth plate.
Fifth, the employment of a secondary helix placed entirely between two
primary helices in inductive apparatuses.
Sixth, the means of increasing the quantity of the operating induced
current by coupling up two or more secondary helices in the manner
described.
Seventh, the improved form of conductor described.
And, last, the means herein described of preserving the outer or protecting
wires of telegraph cables from decay.
In witness whereof, I, the said Charles Weightman Harrison, have here-
unto set my hand and seal, this First day of March, One thousand
eight hundred and sixty-one.
CHA. W. HARRISON. (L.S.)