IMPROVEMENTS IN INSTRUMENTS FOR RELIEVING THE WIRES OF THE ELECTRIC PROVISIONAL SPATION TELEGRAPH OF ATMOSPHERIC
Year: 1854

page_text: LETTERS PATENT to John Nelson Gamewell, of Camden, Kershaw
District, in the State of South Carolina, Ü. S., for the Invention of
"IMPROVEMENTS IN INSTRUMENTS FOR RELIEVING THE WIRES OF THE ELECTRIC
PROVISIONAL SPECIFICATION left by the said John Nelson Gamewell
at the Office of the Commissioners of Patents, with his Petition, on the
29th September 1854.
I, JOHN NELSON GAMEWELL, of Camden, Kershaw District, in the State of
South Carolina, U. S., do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN INSTRUMENTS FOR RELIEVING THE WIRES OF THE ELECTRIC
TELEGRAPH OF ATMOSPHERIC ELECTRICITY" to be as follows; and consists in
an instrument to connect the main wire of the telegraph with the receiving
magnet, or the telegraph instrument, at the terminal & intermediate stations
of the telegraph line, for the purpose of transmitting only the galvanic
current, and discharging into the earth, before it can arrive at the magnet
or telegraph instrument, all atmospheric electricity with which the wires be-
come surcharged when the atmosphere is in a highly electrical state, thereby
obviating all danger of injury to the magnet or telegraph instrument, &
enabling the telegraph to be worked during storms by the employment of one

page_text: or more metallic points in intimate connection with the main line of wire, and
leading within close proximity to, without touching, other metallic points which
communicate with the ground, and are surrounded by air moistened by evapo-
ration from a trough or other suitable means; the said points serving to facilitate
the discharge of atmospheric electricity from the main wire, the moistened air
serving as a conducting medium between the said points, and also to prevent
the fusion of the points; also by obstructing the passage of atmospheric electricity
along the main line, and thereby facilitating its discharge at the said points by
a reduction in the dimensions of the conducting wire at & after its junction
with said points; and also in making those parts of the conductor between the
points of discharge of an inferior conducting material to the discharging points;
also in causing the currents after passing the discharging points to pass through
one or more thin plates of metal with one or more ground points presented in
close proximity thereto.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Nelson Gamewell in the Great Seal Patent Office on
the 26th March 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
NELSON GAMEWELL, of Camden, Kershaw District, in the State of South
Carolina, United States, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of September, in the year of our
Lord One thousand eight hundred and fifty-four, in the eighteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Nelson Gamewell, Her special licence that I, the said John
Nelson Gamewell, my executors, administrators, and assigns, or such others
as I, the said John Nelson Gamewell, 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 of "IM-
PROVEMENTS IN INSTRUMENTS FOR RELIEVING THE WIRES OF THE ELECTRIC TELEGRAPH
OF ATMOSPHERIC ELECTRICITY," upon the condition (amongst others) that I, the
said John Nelson Gamewell, by an instrument in writing under my hand and
seal, 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
:

page_text: 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 John Nelson Gamewell, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement, that is to say:-
This Invention consists in an instrument which is intended to connect the
main wire of the telegraph with the receiving magnet, or the telegraph instru-
ment, at the terminal and intermediate stations of the telegraph line, for the
purpose of transmitting only the galvanic current, and discharging into the
earth, before it can arrive at the magnet or telegraph instrument, all atmospheric
electricity with which the wires become surcharged when the atmosphere is in
a highly electrical state, thereby obviating all danger of injury to the magnet
or telegraph instrument, and enabling the telegraph to be operated during the
severest thunder storm.
The theory upon which this instrument is constructed is based upon the
established principle that atmospheric electricity will leap from one conductor
to another, but that a galvanic current will not pass through the smallest space
without a continuous conductor.
The instrument represented in the accompanying Drawing, and its con-
struction and operation, is described as follows:-
Fig. 1 in the accompanying Drawing is a front view of the instrument;
Fig. 2 is a vertical transverse section of the same in the line a, a, of Fig. 1.
Fig. 3 is a detached view of a portion of the train of wire through which the
galvanic current passes; Fig. 4 is a transverse section, and Fig. 5 a top view,
of parts of the instrument. Similar letters of reference indicate corresponding
parts in the several Figures.
A, B, are two boards, placed edgewise one above the other, and made
adjustable at different distances apart by screws C, C, and kept in proper
longitudinal relation to each other by dovetail bars a, a, which are attached to
A, and fit in dovetail grooves in the ends of B. To the upper face of the board
B are secured a number of studs b, b, c, c, of ivory, or other insulating material,
to support a train of wire D, D, which forms part of the main circuit, and
passes upwards and downwards in a serpentine form, bending rather suddenly,
as shown in Figs. 1 and 3. This train of wire is composed of long pieces d, e, f,
of some inferior conductor, as, for instance, platina or iron, represented in blue
color;
and short pieces g, of superior conductor, as, for instance, gold, silver,
copper, represented in red color, in alternate succession; each long piece d, e, f,
of inferior conductor, starting at the lower bend close to one of the lower studs

page_text: c, c, passing over one of the upper studs b, b, and then passing downwards to be
soldered or otherwise connected with the end d of the next similar piece, by
means of one of the shorter pieces g, g, of superior conductor, which, after
making the connection between f and d, descends, to terminate in a point h,
below the bottom of the upper board B. The reason for this extension to a
point is, that points, sharp angles, &c. are favorable to the discharge of elec-
tricity. The lengths of wire composing this train D, D, diminish gradually in
size from one end to the other, the first being of about 1 of an inch and the
last about of an inch in thickness. The train is connected at the thickest
end with the usual main wire I, which enters the office, and at the thinnest
end with one end of a thin sheet of platina j, from whose opposite end a fine
platina wire k leads to the magnet.
In close proximity to the points h, h, are the points 7, 1, of a series of superior
conducting wires r, r, which are soldered or otherwise attached to the bottom
of a copper trough E, which rests upon the lower board A. These points áré
for the purpose of receiving discharges of atmospheric electricity from h, h; as
will be herein-after more fully explained. The trough, which is shown with its
front partly broken away in Fig. 1, contains water to moisten the atmosphere
in the neighbourhood of the points h, l, to cause the electricity to be readily con-
ducted from h to l, and to prevent the fusion of the points; and to the bottom
of the said trough are attached one or more wires m, of copper, to enter the
ground. On opposite sides of and at a short distance from the platina plate jare
placed two copper plates n, n, which are insulated by the brackets o, o, which
carry them and the platina plate, and attach them to the board B. These
copper plates n, n, are studded all over their inner faces with points p, p, of
superior conducting metal, which are in close proximity to the platina plate j,
(see section Fig. 4, and plan Fig. 5,) and they are connected with the trough E
by copper wires q, q, which are of such form that they will yield readily when
the boards are adjusted by the screws C, C. To facilitate the explanation of the
operation of the instruments, the distinction of color before referred to between
the superior and inferior conductors is observed throughout. The sheet of
platina j, and the wire k, which form parts of the circuit, are colored blue; and
the points 1, 1, and p, p, the trough E, the plates n, n, and the wires q, q, and
m, m, which discharge the atmospheric electricity, are colored red. To proceed
with the explanation of the operation, the wire i brings into the office the
galvanic current, and also any atmospheric current with which it may have
become surcharged; and the whole charge, consisting of the atmospheric and
galvanic currents, is received by the first length of inferior conducting wire in
the train D, D; but in passing from the first to the second length d, e, f, of

page_text: inferior conducting wire, it has to pass for a short distance. along the superior
conducting wire g, which, by reason of its extension in the form of a point,
which is in proximity to a point l, in communication with the ground, is caused
to discharge a portion of the atmospheric electricity, which is received by 1, and
conducted by the trough E and wires m into the ground. The charge, in passing
from the second to the third length d, e, f, of inferior conducting wire through
the second length of superior conducting wire g, is caused in the same way to
make a second discharge from the second point 'h' to the second point l, and the
same effect is repeated until the whole of the atmospheric current is discharged,
and the galvanic current only remains in the wire; or if any of the atmospheric
current still remains when it reaches the platina plate j, it is:received upon the
points p, p, and conducted by the plates n, n, and wires q, q, to the trough E;
from which it passes by the wire m into the ground. The reason for diminishing
the size of the train of wire, D, D, is, that the current, though diminishing in
quantity, may be continually obstructed, and greater facility thereby afforded
for the discharges at the points 1, l... The number of discharging points h, h,
employed is by no means arbitrary; about fifteen or twenty may be successfully
employed. The length of wire between the discharging points h, h, will depend
upon the distance of the trough E from the ground, and the metals of which
the ground wires and the train D, D; are composed. It should be such that
the current will be a little longer in travelling from one to another of the dis-
charge points than through the ground wire. Where practicable, I place the
instrument on or near the ground, and use a ground.wire m, of copper, entering
the ground about four feet, and make the lengths d, e, f, of the train of platina
about four inches in length, as relative conducting powers of copper and platina
are such, that while a current passes through platina a distance of four inches,
it will pass through copper a distance of more than four feet. The short lengths g
of wire I make of silver, of a total length of three-quarters. of an inch; the
part forming the connection between the lengths of platina being one quarter,
and the part extended to form the point h, being half an inch. The trough E
may contain a depth of water of about three-quarters of an inch; but this is
not material, as it only requires to be sufficient to moisten the surrounding air.
The wires r, r, may be all of silver, or the submerged part of copper, and the
pointed parts 1, l, above the water, which should be about a quarter of an inch
in length, of silver.
The only adjustment which the instrument requires is to set the points h; h,
and 1, 1, in the closest possible proximity, without touching, during a highly
electrical state of the atmosphere, and, to move them farther apart during an
ordinary state thereof; but even this adjustment may not be necessary, as the

page_text: present knowledge of electrical phenomena lead to the belief, that when the
points are in close proximity without touching there is no danger of the dis-
charge of the galvanic current. At the terminal stations of the telegraph line
only one of these instruments is required, as the current only enters in one
direction; but at the intermediate stations two are necessary, viz., one at each
side of the receiving magnet or telegraph instrument.
I claim, 1rst, the employment, substantially as herein described, of one or
more metallic points h, h, which are in intimate connection with, and form part
of, the main line of wire, and lead within close proximity to, without touching,
other metallic points 1, 2, which communicate with the ground, and are sur-
rounded by air, which is kept constantly moistened by evaporation from a
trough E, or other equivalent means; the said points h, h, serving to facilitate
the discharge of excessive atmospheric electricity from the main wire, the
moistened air serving as a conducting medium between the points h, h, and
the points 1, 1, in order that the said electricity may be carried into the ground,
and also to prevent the fusion of the points.
2d, the method of obstructing the passage of atmospheric electricity along
the main line, and thereby facilitating its discharge at the point or points h, h,
by a reduction in the dimensions of the conducting wire at and after its junction
with the said points, substantially as herein set forth.
3d, the method of obstructing the passage of atmospheric electricity along
the main line, and facilitating its discharge at the points h, h, by making those
parts of the conductor between the points of discharge of an inferior conducting
material to the discharging points h, h.
4th, causing the currents, after passing the discharging points h, h, to pass
through one or more thin plates j, of metal, with one or more ground points p, p,
presented in close proximity thereto, substantially as herein set forth.
In witness whereof, I, the said John Nelson Gamewell, have hereunto
set my hand and seal, this 25th day of January, in the year of our
Lord 1855.
Witness,
W. E. JOHNSON.
S. H. WALES.
JOHN N. GAMEWELL. (L.s.)