IMPROVEMENTS IN TESTING AND WORKING ELECTRIC TELEGRAPH 8.
Year: 1858

page_text: LETTERS PATENT to William Thomson, Doctor of Laws, Professor of
Natural Philosophy in the University and College of Glasgow, in the
County of Lanark, for the Invention of "IMPROVEMENTS IN TESTING AND
WORKING ELECTRIC TELEGRAPH 8."
Sealed the 23rd April 1858, and dated the 20th February 1858.
ני
PROVISIONAL SPECIFICATION left by the said William Thomson at the
Office of the Commissioners of Patents; with his Petition, on the
20th February 1858.
1, WILLIAM THOMSON, Doctor of Laws, Professor of Natural Philosophy
in the University and College of Glasgow, in the County of Lanark, do'
hereby declare the nature of the said Invention for "IMPROVEMENTS IN TESTING
AND WORKING ELECTRIC TELEGRAPHS," to be as follows; and, for the sake of
distinctness, I have divided the description of the nature of the said Invention
into several parts, that is to say :-.
Part First. I propose to test the insulation of a telegraphic wire by
communicating a charge of electricity to it, and then leaving it with both
eud's insulated, and some part of it connected by a conductor with an instru-
ment for indicating electro-static potential. I propose to use any suitable
electroscope or electrometer for that purpose, but I prefer an instrument
consisting of the following parts:-(1), a testing conductor turned to a true
figure of revolution, and divided into sectors, any or all of which may be
insulated from the ground and from one another; (2), an index moveable

page_text: round the axis of this solid, and which may or may not be guarded from every
other kind of motion; (3), a conductor connecting that index with a body
kept electrified to an approximately constant potential, but not occasioning
any inconvenient impediment to the motion of the index; (4), conductors to
connect one or more of the parts of the testing conductor with the telegraphic
conductor to be tested, and one or more of them with the earth; (5), a case
or cases, with an atmosphere artificiallydried, to preserve the moveable index
from disturbances by currents of air or otherwise, and to maintain good
insulation in the various parts in which insulation is required; (6), a graduated
scale or other arrangement for allowing the position of the moveable index to
be recorded at any time; (7) a guage for testing the potential in the body
mentioned in article (3), which may consist of any electrometer or electroscope
whose indications depend on one independent variable, namely, the potential
to be tested. I prefer an instrument answering to the following description:-
A'conductor turned to a true figure of revolution, or nearly so, to be connected
with the conductor whose potential is to be tested, or with the earth and a
moveable and fixed, or two moveable bodies capable of diverging from one
another round the axis of that figure, and maintained at the earth's potential,
or else to be connected with the conductor to be tested. This instrument may,
if constructed so as to have sufficient sensibility, or if a sufficiently high initial
electrification is given to the telegraphicwireto betested, bealsoadvantageously
used directly to test the insulation of the telegraphic wire.
Second Part. I propose also to test the insulation of a telegraph wire by
making experiments in various ways, so as to compare the freedom which the
defects of insulation allow to electricity passing from the telegraph wire to
the earth when any parts or part of it is put in communication with a source
of electricity with the freedom which is afforded by a standard wire or other
conductor for electricity to pass along itself. One of the ways in which I
propose to carry out this is to apply a powerful battery to send a current
through the standard conductor into the telegraph wire, and then to apply the
electrodes ofa tangent or other galvanometer, or of an electrometer or electro-
scope, such as either of those described, or of any other kind, successively
to the two ends of the standard conductor, and to one end of the same and
the earth.
Third Part. I propose to test a submarine telegraph conductor during the
operation of laying it, by regularly measuring the strength of currents pro-
duced in it by the electro-motive force of a constant battery or batteries, and
that by means of various forms of galvanometer which I have invented for
the special purpose of being used at sea. The chief peculiarity of the different

page_text: kinds of marine galvanometer which I have invented consists in the moveable
magnet, or inoveable indicating body, being supported by means of one, two,
three, or more threads, wires, or fibres in such a manner as to allow it the
requisite degree of freedom to move, and to give it the requisite degree or
stability independently of gravity and terrestial magnetism, and in such a
manner as to be only slightly disturbed by these forces and the reaction of
its own inertia against the inequalities of the ship's motion. The apparatus
which I prefer for testing at any time the position of the body which indicates
the strength of the current by its motion is a mirror attached to this body,
and used either to reflect light after or before or after, and before passing
through one or more lenses, so as to be sent to different parts of a graduated
screen when the moveable body is in different positions.
Fourth Part. I propose to use à double bifilar suspension for the magnet
or other moveable indicating body in a galvanometer, or in a relay, or in any
instrument used for testing or for working electric telegraphs which I have
invented, to give any requisite degree of stability or of instability to the mean
position of equilibrium or balance.
Fifth Part. I propose to use ordinary modes of suspension, also such as
bifilar or single suspension by silk or other fibre or wire, for the moveable indi-
cating body, in telegraphic instruments. When any one of the supporting or
guiding wires or filaments in any of these arrangements, or in the double bifilar
method, is of conducting substance and of sufficient conductivity, and when it is
desired to make or break an electric circuit or electric circuits by the motions of
the said moveable indicating body, I propose to use that wire or filament or
those wires or filaments for bringing into that circuit or those circuits a piece
or pieces of platinum or other metal touching a metal stop, or detached from
the same, according as the moveable body is on one side or the other of its
mean position, or any other suitable arrangement for making & breaking
circuit. When none of the suspending or directing filaments are of conducting
material, and when it is desired to have a circuit or circuits made or broken;
I propose to use a vessel' containing a conducting liquid, and a conductor
connected with the moveable body dipping into it to maintain the unbroken
part of the electric communication between the moveable and fixed parts of
the circuit or circuits.
Sixth Part. When electro-motive forces of different positive and negative
strengths are used to give varied siguals in actual telegraphing, and when it is
convenient to use a relay for transmitting the same system of signals over any.
station by the aid of a local battery, or otherwise, I propose to use a coil or

page_text: a number of different coils, each with one or more moveable magnets in its
neighbourhood, so acted upon by the elastic force of filainents or the deflecting
action of fixed magnets that one set of them will not move when the current
is in one direction, and that one or more of the same set will move when the
current is in the contrary direction, according as the strength of the current
is less or more, and so for the other sets of moveable magnets when the
current is in the contrary direction. When any one of these magnets moves
it breaks or makes, or breaks and makes electric communication in a local
circuit or circuits, so as to cause the corresponding degree of electro-motive
force to be applied to the part of the telegraph line along which the electric
signals are to be forwarded. The same instrument, which may be called a
galvanometric relay, may be used for receiving and recording the message
marking the motions of the different moveable magnets by any suitable method.
Seventh Part-I have also invented another kind of galvanometric relay
or receiving instrument, in which by a single chief moveable magnet or two
magnets, each of which can only leave its mean position in one direction,
two or more magnets, moveable about fixed axes, are turned from their
positions of rest, and so caused to make or break circuits for local batteries or
other electrometers, according as the chief moveable magnet moves througha
less or a greater arc when deflected from its mean position. I propose
to use this instrument, either as a receiving and recording instrument, or in
any operation connected with the manufacture or use of electric telegraphs,
for which it is suited.
Eighth Part. I propose also to use the electroscopes described above, or
any other electroscope or electrometer, giving indications by electro-static force
as a receiving instrument, or an instrument to be used in making comparisons
of clocks, or in giving time or for any other purpose connected with the manu;
facture or use of electric telegraphs worked otherwise than by frictional
electricity for which it is suited. I prefer for this purpose the electroscope first
described above.
Ninth Part. I propose also to use thermal effects produced by radiant
heat reflected from a mirror or reflecting surface of any kind attached to the
moveable indicator of a receiving instrument for the purpose of having the
indications recorded. The thermal effects which I propose to use thus may be
either the melting of wax or of any other fusible substance, or any chemical
or other change produced in the quality or appearance of any substance by
heat or thermo-electric effects in local circuits excited by the radiant heat.
The last-mentioned kind of effects may be used in the construction of a

page_text: third kind of galvanometric relay, in which one, two, or more thermo-electric
circuits will be excited, according to the distance and the direction of any
excursion of the beam of reflected radiant heat, and will produce motions in
moveable magnets, by which the electric currents to do the work wanted may
be checked and permitted to pass, as required.
Tenth Part. I propose to use photography for recording electric signals, as
indicated by motions of a moveable body or moveable bodies, either by light re-
flected from a mirror attached to the moveable body or transmitted by an aper-
ture or transparent part in the moving body, or by influences of a shadow or
image of the moving body or of the shadow or image of any part of it.
Eleventh Part. I propose to use a relay, by which messages shall be trans
mitted simultaneously from two or more submarine cables into a smaller
number of land wires, or a smaller number of submarine wires of shorter
length, or the converse, or generally in any case when it is desired to transmit
messages from one wire or a number of wires into and along a different
number of wires.
The system by which I propose to do this is sufficiently explained by the
plan I would follow in using two or three submarine lines in connection with
one shorter submarine line, or one land line, which is as follows:-Each
singly read or recorded indication from each of the long submarine lines would
by any kind of relay that might be convenient make an electric signal, single
or compound, indicating the degree of intelligence derivable from it alone, and
these secondary electric signals would be made at equal intervals of time from
one another and in general alternately (or in order of succession) as they
come from the submarine lines. When itcan be arranged that the submarine
lines are to be worked at the remote end, so as to send signals at equal
intervals of time in recurring or..er one after the other, the kind of relay
which will be required will be merely one in which signals from two different
submarine lines are forwarded indifferently at the instant as they come. When
this cannot be so arranged, a mechanical arrangement must be made in the
relay to keep back signals which have come in too soon from any of the
submarine lines, and to transmit all that come in the regular order of their
arrival.
Twelfth Part. I propose to use electric sparks excited by a Ruhenkorff
coil, or any other convenient instrument, and passing between any part of the
moveable body indicating electric signals and a sheet of matter fixed or carried
along by a regular motion near, it to record by impressions, chemical changes,
or perforations produced by these sparks, the motions of the moveable body;
or to use electric currents sent through a conducting liquid covering part of the

page_text: moveable body, so as to make impressions, chemical or other, on a sheet also
covered by the liquid. In using electric sparks to record the indications of a
moveable body in a galvanometer or galvanometric relay employed for.
telegraphic purposes, I propose to have a regular succession of sparks follow_
ing one another at equal intervals of time, each making a mark on the paper
or other sheet receiving the impression or perforation.
Thirteenth Part.-I propose, when convenient or desirable for any purpose,
to use an apparatus by means of which electric signals may be read off by
observing the degrees, greater or less, of motion of a moveable body directly;
or by observing a spot of light reflected from a mirror carried by the moveable
body and thrown on a graduated screen.
Fourteenth Part.-I propose, in long lines of submarine telegraphs, to use
apparatus by which, for a single signal, an electric current of a stated strength
is as rapidly instituted in a telegraph wire as possible, and maintained as
nearly as possible at the stated strength until an indication is taken from it by
any of the receiving instruments, galvanometers, relays, electroscopes, or
electrometers, described above, or by any other which may be convenient.
The indication must be of such a kind that from it, with due allowance for the
electric condition of the wire as effected by previous operations, it may be
possible to estimate what was the strength of current arranged for at the
remote end. According to the strength of current (positive or negative) thus
investigated, one number or another, one letter or another, one word or
another, one piece of intelligence or another, is read off according to a pre-
arranged code. I should use a Daniell's or other constant battery, or any
other electrometer by which definite and sufficiently exact measures of electro-
motive force can be applied for making electric signals of this kind. I propose
to use the following plan for making the current as rapidly as possible
approach the stated strength for any signal, and that whatsoever may have
been the strength employed in the signal immediately preceding it, or for any
of the preceding signals:-When commencing with the wire unelectrified, a
*stronger electro-motivo force than that required to maintain the current at the
stated strength is first to be applied for a short time, and after that, the electro-
motive force just required to maintain a current at the stated strength is
applied and continued until the time comes to make the next signal. An
electro-motive force, differing (positively or negatively) from this one by a
greater amount than that by which the electro-motive force corresponding to
the new signal differs from it, is next applied for a short time, after which the
electro-motive force simply required to maintain the stated strength corre-
sponding to the new signal is applied, and held on until it is time to commence

page_text: a third signal, and so on. I propose, also, in some cases to use the following
plan: To apply constant battery power during a certain measured interval of
time, then another constant battery power during another equal interval
of time, and so on; these degrees of power being each determined by
calculation or otherwise, so as to compensate, so far as is required, the residual
effects of preceding operations, and at the same time to produce a new effect
constituting or contributing towards a new signal.
Fifteenth Part.-When it is desired to work through a submarine line or
through a very long air line in both directions at once, I propose to keep the
coil, coils, or conductor of the galvanometer relay or other instrument used
forreceiving signals in electric operation in connection with the telegraphicline,
only during certain intervals of time, not constantly; and I propose to do this
also, when it is convenient to do so for any reason whatever, whether when
working in both directions at once or not. By this means, I propose to
eliminate, from à galvanometer or other instrument used for receiving signals
at the same end as that from which signals are being sent, the comparatively
violent action which is experienced in the part of a telegraph conductor next
the end from which a message is being transmitted, or in wires between it and
the earth, during rapid changes of its electric potential.
Sixteenth Part. I propose either to compensate or to allow for the residual
effects experienced from preceding signals, so that the indications of the
receiving instrument in use may be either not sensibly affected by them, or that
the indications it would have given had it not been affected by them may be
estimated.
Seventeenth Part.-In working in both directions at once, I propose to
make the beginning of each electric signal as nearly as possible simultaneously
at the two ends or alternately at definite intervals of time; and to do the like
with everychange of battery,application, or of electro-motive force or potential;
and for that purpose I use a mechanical apparatus at each end, regulated
according to a clock, or mechanically by clockwork; and I propose to have
electric comparisons of time between the two ends made as frequently as is
necessary to make these two mechanisms keep time with one another as
accurately as is required.
Eighteenth Part.-I propose to use, when convenient or when desired for
anyobject, two or more different galvanometers or other receiving instruments,
either each self-recording, or each read off by one or more observers, or all read
off by one observer but thrown into electric operation in connection with the
elegraph wire during intervals regulated by the same mechanism for keeping
ime as that which is used in making the signals.

page_text: Nineteenth Part. -For checking the motion of any moveable indicator in a
receiving instrument after its indication has been read off, I propose to use a
magnet moved by mechanism or a vessel of liquid brought up so as to cover
part of the moveable body, and removed again, if necessary, when a new
indication is to be taken, or by turning or otherwise moving the filaments or
wires by which the body is supported, when it is so supported, or by other
suitable methods.
Twentieth Part. For increasing,diminishing, or regulating, to any desired
degree, the stability of the moveable body of a galvanometer or galvanometric
relay, or of any moveable body, part of which is a magnet or an electro-
magnet, or a body in any way under the influence of magnetic force, I propose
to use either fixed steel magnets, or a fixed electro-magnet, or wires conveying
currents of electricity, either in conjunction with any of the modes of sus-
pension described above or when the moveable body is supported in any
other way.
Twenty-first Part-In the use of galvanometers or galvanometric relays, or
of any other kind of relay or receiving instrument, I propose, in order to com-
pensate the effect of electrification of the telegraph wire remaining over from
previous signals, to use in the neighbourhood of the moveable indicating body
an electro-magnet or coil of wire conveying a current instituted and regulated
to produce the desired effect, or a steel or other magnet moved so as to
produce the desired effect. When it is not convenient to make allowance for
such residual effects from previous signals by calculation or otherwise, and
when they are of such an amount as to exercise a sensible disturbance if not
compensated, I propose to use similar apparatus under similar conditions in
sending messages through either a land or a submarine line in both directions
at once, for the purpose of compensating the effect on any receiving instrument
due to signals transmitted in the direction contrary to that from which the
signals to receive which it is employed are coming.
Twenty-second Part.-I propose to use two mirrorsattached to themoveable
bodies of two galvanometers to be excited by currents from two separate lines,
and I propose to transmit light so as to be reflected from these two mirrors
successively and thrown on a screen, so as to give a visible effect, or by
photographic or thermal influence, a recorded effect, by which any lines,
figures, letters, or symbols drawn or written at one station upon an instrument
adapted to give different dègrees of electro-motive force to the two lines
according to the two independent variables thus dealt with, may be written,
drawn, or made visible at another station. For transmitting a line drawing
or writing, of any kind by telegraph, I propose to add a third wire, which will

page_text: be so connected & arranged, that when the tracing point is lifted from the
surface on which the curve is drawn at the one station, the indicating or
marking beam of light will be cut off at the other station.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
:
by the said William Thomson in the Great Seal Patent Office on the
19th August 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
THOMSON, Doctor of Laws, Professor of Natural Philosophy in the University
and College of Glasgow, in the County of Lanark, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of February, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Thomson, Her special licence that I, the said William
Thomson, my executors, administrators, and assigns, or such others as I, the
said William Thomson, my executors, administratore, 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 lawfullymight make,
use; exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN TESTING AND WORKING ELECTRIC TELEGRAPHS," upon the condition
(amongst others) that I, the said William Thomson, 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 William Thomson, 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 (reference being had to the Drawings annexed) that is
to say:-
For the sake of distinctness I have divided the description of the said
Invention into several parts, that is to say,
Part First. I test the insulation of a telegraphic wire by communicating a

page_text: charge of electricity to it, and then leaving it with both ends insulated, and
some part of it connected (and when I use the term "connected" here and
throughout the Specification, I mean, unless otherwise expressed, connected by
a wire or other conductor of electricity,) with an instrument for measuring
electrostatic potential, and leaving it so connected, and observing the diminu-
tion of its potential in a certain time. "Potential" is a term the mathematical
definition of which is well known to all persons conversant with the mathe-
matical theories of electricity, magnetism, and attracting forces generally; for
the present purpose it is sufficient to say, that the "electrostatic potential," or,
as I shall call it for shortness simply the "potential," for any point A in space
is a quantity depending on the position and electrical state of all the bodies
which act at the point A (being in strictness all the bodies in the universe,
but with sufficient accuracy for the present purpose all the electrified bodies
in the neighbourhood of A.), and such that the difference between the values
of the potential at the point A, and the potential at any other point. B is a
measure of the tendency of electricity to flow from A to B, or vice versa,
supposing A and B connected by a small conducting wire. It follows from
this, that where there is equilibrium, the potential at every point of an electrified
insulated conducting body, including every other insulated conducting body
connected with the first by wires or other conductors, is the same, and may be
measured by connecting by a conducting wire any part of the conducting body
with any insulated electrometer of sufficient delicacy. For measuring the
potential I use any suitable electrometer. Electrometers hitherto in use, such
as the gold leaf or the pith ball electrometer, are not sufficiently sensitive to
measure the potential, which can be conveniently communicated to a telegraph
wire; I therefore use one of those next described. One of the electrometers
which I use, and which from its indications depending on the potential of the
indicator, as well as on the difference of potentials to be measured, may be
called the heterostatic electrometer, consists of the following parts:-
1. A testing conductor, which consists of two, four, or any even number of
separate pieces of metal, but which may be most easily described by first suppos-
ing them to form one piece, and then describing how that piece is to be divided.
The testing conductor, then, consists of a piece of metal turned to the form of
a true solid of revolution of such a shape that when the indicator hereafter
described turns about the axis of figure of the solid the end of the indicator
may be exposed to the action of as large a part as conveniently may be of the
testing conductor. Thus the testing conductor may be as shewn in the Figure,
a flat circular ring placed horizontally, or it may be a circular plate placed
horizontally, the end of the indicator in either case moving just over the upper

page_text: surface of the testing conductor; or it may be a cylindrical ring, with its axis
of figure vertical, the end of the indicator then moving just inside the ring; or
it may be such a flat circular ring or plate surrounded with such a cylindrical
ring, so as to be of the shape of a shallow compass bowl, the end of the
indicator then moving as the end of the ordinary compass needle; or it may
be of the shape last described, with the addition of a flat circular ring placed
above the indicator, some additional contrivance which may be easily arranged
being then made to allow the position of the indicator to be observed. This
testing conductor is to be divided into two, four, six, or any even number of
equal sectors, by slits at the intersections with it of planes passing through the
axis of figure, and the sectors separated from each other by the smallest
possible interval that will prevent actual contact; the thickness of a sheet of
paper will be sufficient if the instrument be well made and carefully adjusted.
It will be convenient first to describe the instrument and the mode of using it
when the testing conductor is divided into two sectors, and then to describe
the variations caused by dividing the testing conductor into four or more
sectors.
2: An indicator. By the term " indicator" I mean here and in the following
parts of theSpecification, a bodyacted on bythe forces required to bemeasured,
and suspended or supported in such a wayas by its angular motion to measure
or indicate the amount or change of those forces. The particular form and
construction of the indicator in each case will be described.
In the instrument now describing the indicator consists of a thin conducting
slip of metal, suspended at one end by a nonconducting filament, and kept
horizontal by a counterpoise, and kept at a constant or sensibly constant
potential by means of the conductor next described.
3. A conductor, connecting the indicator with a body of large electrical
capacity, kept electrified to a constant potential, the difference of which from
the potential of either of the bodies the difference of whose potential is to be
measured is very large compared with the last-mentioned difference.
4. A conductor to connect one of the parts of the testing conductor with
the telegraphic wire to be tested, and another conductor to connect the other
part of the testing conductor with the earth, or with another part of the
telegraphic wire or any other body, the difference of potential between which
and the first part of the telegraphic wire is to be measured.
5. A case or cases to enclose the parts herein-before described with an
atmosphére artificially dried to preserve the indicator from disturbances by
currents of air or otherwise, and to maintain good insulation in the various
parts in which insulation is required.

page_text: 6. A graduated scale or other arrangement for allowing the position of the
indicator to be observed at any time.
.
The principle of the action of the instrumentis the following:-When both
parts of the testing conductor are in connection with one another or otherwise
electrified to the same potential, they do not disturb or affect the position of the
indicator, and this by virtue of the shape of the testing conductor, being that
of a solid of revolution, having its axis of figure coincident with the axis of
motion of the indicator. If it were of any other shape there would be an
inductive effect between it and the electrified indicator, which would give the
indicator a tendency to point in particular directions. The indicator is now
to be adjusted by the torsion head, so that its end rests immediately over or
opposite one of the slits. This having been done, when the two parts of the
testing conductor are electrified to different potentials, the indicator deviates
to the side of that part, the potential of which differs most from the potential
of the indicator. By keeping the indicator electrified in manner herein-
before mentioned to a high potential, either positive or negative, the effects of
induction between the indicator and the testing conductor are obviated, and
the sensibility of the instrument is greatly increased, and we have the further
advantage of being able to distinguish by the direction in which the indicator
moves whether the potential of the conductor tested or the difference of
potentials of the two is positive or negative, a result not given directly by
an idiostatic electrometer such as that next described. When we wish to
measure the difference of potential between two conductors we bring one part
of the testing conductor into connection with one of the conductors, the other
into connection with the other, and observe the angular deflection of the
indicator, or we may turn the torsion head till the indicator is brought back
to its original position, and observe the amount of torsion required. If one
of the two conductors so tested is the earth, then as its potential is considered
as zero, we get a measure simply of the potential of the other conductor.
In the instrument as described there is the disadvantage that the indicator
is subject on being highly electrified to be tilted down or otherwise drawn
into contact with the testing conductor and to be discharged. This is obviated
by dividing the testing conductor into four equal sectors, and connecting
two opposite quadrants with the conductor to be tested, the other two with
the earth. The indicator then is suspended by its centre, and made to extend
equally in both directions from the suspending filament, and the tendency to
tilting or to be otherwise drawn into contact with the testing conductor is
obviated, and the power of the instrument doubled.
Thetestingconductormaybe divided intosix equal sectors, and three alternate

page_text: sectors connected with the conductor to be tested, and the other three with the
earth. In this case the indicator will be of the form of a three-rayed star,
the rays in the position of equilibrium being immediately over or opposite
alternate slits, and in like manner the testing conductor may be divided into
eight or any even number of sectors, the indicator being in the form of a star
with half as many rays as there are sectors, but it is not probable that any
increase above four sectors will compensate for the increased expense and
trouble in construction and adjustment.
Figure 1 shews, on a scale of about one quarter of the actual dimensions,
one mode of constructing this electrometer in its simplest form, herein-before
described. A, B, testing conductor, consisting of a flat circular ring divided
into two sectors by very narrow slits at C, C, and having a scale marked on
its upper surface. Each sector has an insulating support or supports with
three levelling screws to adjust it to a truly horizontal plane and to a given
elevation, permitting it also the requisite horizontal motion, and steadied by
springs, for which clamps may be substituted. D, indicator, consisting of a
flat thin slip of aluminium or other suitable material with a counterpoise M.
E, fibre of glass or other suitable material, by which the indicator is sus-
pended, with a torsion head and graduated circle of the usual construction;
F, conductor connecting the indicator with the electrified body I, which con.
ductor may consist of a wire dipping into a cup containing a conducting
liquid; this mode of connection will be again mentioned under the head of
the fifth part of my Invention. G, conductor for connecting one sector of the
testing conductor with the conductor to be tested; H, conductor for con-
necting the other sector of the testing conductor with the earth or the other
conductor to be tested; I, electrified body, which in the Figure is a Leylen
jar charged to a high potential in the usual way from an electrical machine,
the conducting wire being in connection with the internal coating of the jar,
and the external coating in connection with the earth; K, glass cylinder or
other case containing a dry atmosphere; L, conductor for charging and
testing the body i; N, vessel containing sulphuric acid or other absorbent
material for drying the air in the case.
For testing the insulation of the telegraphic wire in cases in which it is
desired to give it a very high potential in testing it, and also for testing the
amount and permanency of the potential in the electrified body I, part of the
heterostatic electrometer lierein before described and generally for measuring
electrostatic potential where a less delicate measure is required than that for
which the first-described electrometer is adapted, I use an electrometer which
from its indications depending simply on its own potential as communicated

page_text: by connection with the bodies to be tested, may be called an idiostatic
électrometer, and which answers to the following description: :-
An indicator, consisting of a slip of metal suspended by its centre, and con-
nected with two pieces of metal fixed near its ends, and so arranged that the
indicator can swing freely in one direction in a horizontal plane, and is stopped
by the pieces of metal from swinging in the other. If this combination be
insulated and brought into connection with the electrified conductor to be
tested, whether its potential be positive or negative, the indicator is deflected.
By enclosing it in a hollow metallic cylinder with metallic ends, herein-after
referred to as the drum, in contact with the earth, but not with the indicator,
the deflection of the indicator is increased, and the indicator is at the same
time protected from the effects of irregular inducti on fromsarrounding bodies,
and conversely if the drum be insulated and connected with the electrified
conductor to be tested, and the combination of pieces of metal and indicator
be connected with the earth, a like amount of deflection of the indicator is
produced. Figure 2 shews, on a scale of abo it one-quarter of the actual
dimensions, one mode of constructing this idiostatic electrometer. A, vessel
containing sulphuric acid, or other absorbent material to dry the air in the
air-tight case C, which stands on hollow pillars B, the inter iors of which make
a communication between A and C; D, a cylindrical metallic drum, with its
axis of figure vertical, enclosed in the case C, and shewn by dotted lines;
this drum is supported by glass or other insulating pillars, which traverse the
hollow pillars, and it has in the centre of its upper and lower ends circular
holes, large enough to permit the tube F to pass through without contact. E,
insulated conductor, by which the drum D can be connected with the body to
be tested; F, vertical metal tube, capable of being turned into various
positions about its vertical axis; the position of this tube is indicated by an
index attached to it, which points to a circular graduated scale on the top of
the case C; the vertical tube F traverses the case C and drum D; its con-
struction within the diumat the point marked H will be afterwards described;
at I it has or may have a glazed opening, to permit the access of light to a
mirror to be afterwards mentioned. G, torsion head, carrying a fibre or wire
which traverses the axis of the tube F, as shewn by a vertical dotted line;
from G down to H this fibre in the instruments I have constructed is of glass,
but if a metallic wire sufficiently fine could be procured I should prefer it, and
in that case the wire below H, and the cup of conducting liquid afterwards
mentioned, might be dispensed with; at H the fibre or wire carries the
indicator, to be afterwards mentioned; from the indicator a wire goes down
and' communicates with the tube F, and with the earth by dipping into a

page_text: small vessel of conducting liquid. The deflection of the indicator is indicated
either by the reflection of light from a small mirror carried by this wire at I,
or by the position of a very light index carried by it at K, moving within a
glass case, and pointing to a graduated arc. Either or both of these methods
may be employed. Figure 3 is a horizontal section of the interior of the
drum D, near the level of the point H. L is a horizontal section of the
vertical tube F, which here has two small openings in its opposite sides, to
allow of the passage and motion of the indicator N, N; M, M, are two
metallic arms projecting from the tube at opposite edges of its two openings.
The indicator N,N, is of aluminium, or other suitable metal, and is carried by
the fibre or wire before mentioned. When the electrical condition of the
apparatus is undisturbed, the tube and the suspending fibre or wire are to be
adjusted until the indicator N,N, hangs nearly in contact with the arms M, M.
When the tube F and the indicator are connected with the earth, and the
drum D with the conductor which is to be tested, the bar N, N, is repelled by
the arms M, M, and the repulsive force measured by the deflection of the
indicator, or by the torsion of the suspending fibre or wire required to bring
back the indicator to its original position, measures the difference between the
potential of the conductor tested and of the earth.
This difference of potential may also be measured by connecting the con-
ductor to be tested with the tube and indicator, insulating them from the earth,
and bringing the drum in connection with the earth, but this mode of
using the instrument. I have found to be less convenient than that first
described; in this way too, the difference of the potentials of any two con-
ductors may be measured.
Second Part.-I also test the insulation of a telegraphic wire by comparing
its resistance to the flow of electricity from a constant source with the resis-
tance of a standard wire to the flow of electricity from the same, or another
constant source.
A standardwire is one perfectly insulated, and whose resistance to electro-
motive force is known, and which resistance may be conveniently expressed in
terns of the resistance of a certain length of the telegraphic wire to be tested
if perfectly insulated. Several standard wires of different resistances should be
at hand to be used. One of the ways in which I make the observation, is by
applying a battery to send a current through the standard wire into the
telegraphwire, insulated as much as possible,and then to apply the electrodes
of a tangent galvanometer, or other galvanometer, or of an electrometer, such
as either of those described, or of any other kind, first, to the two ends of the
standard wire, and next to the end of the standard wire which is connected

page_text: with the telegraph wire to be tested and to the earth. The resistance of the
standard wire is to the resistance to be tested, as the difference of potentials
at the two extremities of the standard wire is to the difference between the
potentials at the end of the standard wire in connection with the telegraph.
wire and the earth.
Third Part. I test a submarine telegraph wire during the operation of
laying it by measuring from time to time the strength of currents produced in
it by the electro-motive force of a constant battery or batteries, and that by
means of various forms of galvanometerwhich I have invented for the special
purpose of being used at sea. The chief peculiarity of the different kinds of
marine galvanometer which I have invented consists in the moveable magnet,
which is the indicator, being supported by means of one, two, three, or more
threads, wires, or fibres in such a manner as to allow it the requisite degree of
freedom to move, and to give it the requisite degree of stability independently
of gravity and terrestrial magnetism, and in such a manner as to be as little as
possible disturbed by these forces, and by the reaction of its own inertia
against the inequalities of the ships' motion. When one thread, wire, or fibre
is used the indicator is fixed to the middle of and at right angles to the
thread, wire, or fibre which should pass as nearly as possible through the
centre of gravity of the indicator. The thread, wire, or fibre is tightened by
screws, and adjusted by torsion heads at both ends. When two or four
threads, wires, or fibres are used, then the inode of support is that described
in the fourth part of this Specification.
For the purpose of giving increased steadiness to the indicator, I sometimes
use, in addition to the mode of suspension herein-before indicated, a fixed mag-
net placed in a suitable position in its neighbourhood. By the word "magnet"
I mean any body which excrts magnetic force. The apparatus which I prefer
for observing at any time the angular deflection of the indicator, is a mirror
attached to that body and reflecting a ray of light either after or before, or after
and before the ray passes through one or more lenses, so as to be sent to, and
brought to a focus at different parts of a graduated screen, as the indicator
assumes different positions. The method of observing the position of the in-
dicator will again be referred to under the head of the thirteenth part of my
Invention.
The frame of the galvanometer is fixed by screws to one end of a board, at
the other end of which is a lamp having a camphine or other very brilliant
flame for throwing a beam of light, and also a graduated screen on which the
beam reflected from the mirror is thrown, so as to indicate the angular posi-
tion of the indicator. The board is supported from below by means of springs

page_text: on a stand fixed to the ship. For this purpose I prefer spiral springs of the
kind known as furniture springs. Round the stand and fixed to it is a rail,
from which springs or elastic bands go to a rail fixed to the board, so as to
moderate the horizontal oscillation of the board and galvanometer.
Fourth Part. I use a double bifilar suspension for the indicator in any
electrometer, galvanometer, relay, or generally in any instrument used for
testing, or for working electric telegraphs by means of an indicator. This
suspension I have invented to give any requisite degree of stability, or of
instability to the indicator in any position of equilibrium.
Figures 7 and 8 shew how this part of my Invention is performed. In each
of those Figures G H represents the indicator and A. I, B K, C I, DK,
four fibres or wires, by means of which the indicator is attached to four points,
A, B, C, D. The dotted line L, M, is an imaginary line perpendicular to the
two lines A, B, C, D, which join the points of suspension in pairs, and also
perpendicular, or nearly so, to the plane in which the indicator moves. The
dotted line E, F, represents the position in which the indicator tends to place
itself when undisturbed; and the deviation of the indicator from that position,
that is, the angle between G, H, and E, F,indicates the direction and amount
offorcederived from the arrangement by which the indicator is acted on, tending
to make it return to or further diverge from its position of equilibrium,
according as the equilibrium is stable or unstable. When A, B, is parallel
to C, 1), as in Figure 7, E, F, is also parallel to A, B, and C, D; the equili-
brium is then stable and the stability greatest. As A, B, or C, D, or both,
are moved so as not to be parallel, as in Figure 8, the direction of E, F, is
intermediate between the directions of A, B, and C, D, and the stability is less
than in the former case; and the more the direction of A, B, differs from
that of C, D, the less is the stability, until the directions of A, B, and C, D,
differ by more than one hundred and eighty degrees, when (if the indicator
is supported by fibres having no sensible independent elasticity of torsion)
the equilibrium is unstable; and stops, at equal distances on each side of the
position of the equilibrium, are to be used to prevent the indicator from
diverging by more than a convenient angle from the position of equilibrium.
When the indicator is supported by wires having an independent elasticity of
torsion, this elasticity increases the stability, or diminishes the instability, which
the indicator would otherwise have from the mode of suspension; and a greater
angular separation betwe en A, B, and C, D, must be used to give the same
degree of stability and instability as in the case of fibres without sensible
elasticity of torsion.
The stability is adjusted-to any required degree; so as to adapt the instru

page_text: 'ment to the measurement of more or less intense force, by making one or both
.of the two pieces A, B, and C, D, to which the fibres are attached respect-
tively, capable of rotation about the line L, M, so that the lines A, B, and
C, D, can be adjusted to and fixed at such relative angular positions as shall
be found by trial to give the degree of stability or instability required under the
'circumstances of the case.
When the indicator is directed by fixed magnets or otherwise, and it is
desirable to have the means of diminishing its stability, then it may be sus-
pended by a double bifilar suspension in the mode described, arranged in a
manner which would, independently of the magnet,give instability. This will
diminish the too great stability which it has from the magnet.
Fifth Part. In using the method of suspension described in Part 4,or any
of the ordinary modes of suspension by fibres or wire, when any one of the
supporting or guiding wires or filaments in any of these arrangements is of a
conducting substance, and of sufficient conductivity, and when it is desired to
make or break an electric circuit or electric circuits by the motions of the
indicator, I use that wire or filament, or one or more of those wires or filaments,
for bringing into circuit a piece or pieces of platinum or other metal attached
to the indicator, touching a inetal stop or detached from the same, according as
the indicator is on one side or the other of its mean position, or any other
suitable arrangement for making and breaking circuit. When none of the
suspending or directing filaments are of conducting material, and when it is
desired to have a circuit or circuits made or broken by the motion of the
indicator, I use a vessel containing a conducting liquid, and a conductor cou-
nected with the indicator dipping into the conducting liquid to maintain the
electric-communication between the indicator and the fixed parts of the
circuit or circuits.
Sixth l'art. I use electro-motive forces, of several different positive and
negative strengths, to give different signals in telegraphing; and for this
purpose, and also when it is convenient to use a relay for transmitting such a
system of different signals through any station by the aid of a local battery, or
otherwise, I use a coil with several moveable magnets or indicators in its
neighbourhood acted on by the coil when a current is transmitted, and also so
acted upon by the tension, or torsion, or both of filaments, or the deflecting
action of fixed magnets other than the earth, and by stops, that one set of the
indicators will not move when the current is in one direction, but will move if
a sufficient strength of current in the opposite direction be applied, and vice
versâ, as to the other set of indicators. The position of the indicators and the
elastic or other force which opposes their motion are so arranged, that, for the

page_text: move;
lowest strength of current in one direction, one indicator of one set only will
for the second strength, two of the same set will move; for the third
strength, three, and so on; and so, vice versa, for the other set of indicators,"
when the current is in the contrary direction. When these indicators are
used simply as receiving instruments, and read off directly by an observer, the
number of indicators which move distinguishes the different signals; if used
with a relay as a transmitting or recording instrument, then, when any one of
these moveable magnets moves, it breaks or makes, or breaks and makes
electric communication in a local circuit or circuits, so as to cause the corre-
sponding degree of electro-motive force to be applied to the partofthetelegraph'
line along which the electric signals are to be forwarded, or to the recording
apparatus.
Seventh Part. I have also invented another kind of galvanometric relay or
receiving instrument, consisting, besides the ordinary parts, of,
First, a single primary magnet or indicator moveable in a horizontal plane,
and when in a position of equilibrium poiuting to the magnetic north, and
which, by ordinary modes, may be made to move to the east when the
current is one direction, and to the west when the current is in the other'
direction; or two primary magnets or indicators, one of which is prevented by
stops from moving to the east, and the other is prevented by stops from moving
to the west.
Second,two or more small secondary magnets or indicators moveable in the
same horizontal plane about fixed axes; these axes are placed at successive
distances along and outside the arc north or south, but (to fix ideas) I will
say north of the primary indicator. One secondary indicator may be due
north of the primary indicator, and without stops; one half of the rest of the
secondary indicators are placed at successive distances to the east, each with a
stop which prevents its north end from moving to the east, and the other half
at like successive distances to the west, and each with a stop which prevents
its north end from moving to the west. When the primary indicator is in its
undisturbed position all the secondary indicators are held against the stops,
except the first or central o e, which is then also pointing north. When a
positive current of the first strength is sent through the wire, the primary indi-
cator,or one of the two primary indicators, moves through a given angle to the
east or west; but say, (to fix ideas,) to the east, and moves only the first of thie
easterlyset of thesecondary indicators, the north end of such secondary indicator
moving to the west. When a positive current of the second strength is sent
through the wire, the primary indicator is deflected through a greater angle
to the east,and the second of the same set of the secondary indicators is moved.

page_text: When a positive current of the third strength is sent through the wire, the
primary indicator is deflected through a still greater angle to the east, and the
third of the same set of the secondary indicators is moved, and so on; and so
vice versâ, as regards the west set of secondary indicators when negative
currents of the first, second, and third strength are sent through the wire.
The motions of the secondary indicators may be observed and read off or
recorded in any of the ways now in use, or in any of those described in this
Specification adapted to the purpose, or may be used to make or break contact
for local batteries, and thus be used as a relay for a transmitting or recording
instrument, or in any operations connected with the manufacture or use of
electric telegraphs for which it is suited.
Although in what precedes I have, for distinctness, supposed the primary
andsecondary indicatorsin their undisturbed position to point north and south,
they may often be more conveniently directed in some other direction by fixed
magnets, or by any of the modes of suspension described herein; in that case,
for north, south, east, and west, in the preceding description, must be sub-
stituted corresponding directions relative to the actual positionofundisturbed
equilibrium.
Eighth Part. I use either of the electrometers described in the first pare
as a receiving instrument, or an instrument to be used in making comparisons
of clocks, or in giving time, or for any other purpose connected with the
manufacture or use of electric telegraphs worked otherwise thanby frictional
electricity. I prefer for this purpose the electrometer first described above.
Ninth Part.-I also use thermal effects produced by radiant heat reflected
from a mirror or reflecting surface of any kind, attached to the indicator of a
receiving instrument, for the purpose of having the indications recorded. The
thermal effects which I thus use may be either, first, the melting of wax or
of any other fusible substance, forming a layer which is moved with a steady
motion across the line of motion of the beam of radiant heat, or any chemical
or other change produced in the quality or appearance of any substance by
heat; or, secondly, thermo-electric effects in local circuits excited by the
radiant heat. The last-mentioned kind of effects may be used in the construc
tion of a third kind of galvanometric relay, in which one or two or more
thermo-electric circuits are excited according to the distance, and thedirection
of any excursion of the beain of reflected radiant heat,and produ.e motions in
moveable magnets or indicators, by which the electric currents to do the work
wanted may be checked or permitted to pass as required.
Tenth Part. I use photography for recording electric signals as indicated,
by motious of an indicator or indicators, either by light reflected from a mirror

page_text: attached to the indicator, or transmitted by an aperture or transparent part in
the indicator, or by influences of a shadow or image of the indicator, or of the
shadow or image of any part of it. In performing this process, I use a band.
or piece of photographic paper or other substance sensitive to photographic
action; which by any ordinary mechanism I cause to travel at a steady rate
across the line of motion of the indicating beam whose movements are recorded
by the marks made on the paper or other sensitive substance.
Eleventh Part. I use a relay, by which messages are transmitted simul-
taneously from two or more submarine cables into a smaller number of land
wires, or a smaller number of submarine wires of shorter length, or the
converse, or generally in any case when it is desired to transmit messages from
one wire or a number of wires into and along a different number of wires.
The system by which I perform this is sufficiently explained by the plan I
follow in using two submarine lines in connection with one shorter submarine
line or one land line, which is as follows:-Each singly read or recorded indi-
cation from each of the long submarine lines, makes, by any kind of relay that
is convenient, a corresponding secondary electric signal, single or compound
and these secondary electric signals are made at equal intervals of time from
one another, and in general alternately, as they come from the two submarine
lines. When it can be arranged that the submarine lines are to be worked at
the remote end so as to send signals at alternate intervals of time, the kind of
relay which is required is merely one in which signals from two different sub-
marine lines are forwarded indifferently at the instant as they come. A useful
application of this part of my Invention consists in giving the means of sending
two or more messages at the same time along the same telegraph wire from
different instruments at the same station. Each instrument has a conductor
leading to the telegraph wire. The keys or handles by which each instrument
is worked are kept locked, so as to be incapable of motion, except during
certain definite periods, during which the keys or handles of all the other
instruments are locked, so that the keys of one instrument only can move at
any one time, and the keys of all the instruments used can be successively
moved. This may be accomplished by various mechanical arrangements; for
example, each key may have a pin projecting from its under side; and below
the row of pins there may be a cylinder rotating by clockwork at an uniform
rate, with a longitudinal groove of a certain width along it, so that the keys of
the instrument in question can only be depressed during the period when the
groove is below the row of pius. Then, either by placing all the sets of keys
above one cylinder, having a groove for each instrument so arranged that the
keys of no two instruments are ever above the corresponding groove at the

page_text: same time or by having a separate cylinder under the set of keys of each
instrument, but the cylinders rotating atone and the same speed and so arranged
that the keys of no two instruments are ever opposite the corresponding groove
at the same time, the rows of keys of the several instruments may be liberated
in succession at successive times, so that two or more clerks may work at two
or more instruments at the same time, each sending a separate message, and
the two or more messages will be transmitted together by successive alternate
signals, which can be arranged so as to separate the messages at the distant
station according to a preconcerted system; for example, suppose that at one
station there are two instruments and two clerks, and that at the other station
thefollowing seriesofsignalsarrive, P,F,R,R,O,E,T,E,E,T,C,R,T,A,I,D,O,E,N,
a clerk at the second station taking these letters alternately, finds that the
first clerk transmitted the word PROTECTION, and the second the words
FREE TRADE. În any case in which signals can be transmitted by the
conductor at a more rapid rate than one clerk can work his transmitting
instrument, this method will save much time. The particular mechanism
employed for unlocking the several sets of keys in succession may be varied.by
any one who is familiar with machine or instrument making. I have already
described one kind of mechanism for that purpose; another kind in which
cams and levers are employed, will be herein-after described under the head of
the fourteenth part of my Invention.
Twelfth. Part. I use electric sparks excited by a Ruhmkorff coil or any
other convenient instrument, and passing between any part of the indicator
and a sheet of matter fixed or carried along by a regular motion near it to
record, by impressions, by chemical changes, or by perforations produced by
these sparks, the motions of the indicator. I also use electric currents sent
through a conducting liquid, covering part of the moveable body so as to make
impressions, chemical or other, on a sheet also covered by a liquid. In using
electric sparks to record the indications of a moveable body in a galvanometer
or galvanometric relay employed for telegraph purposes, I employ a regular
succession of sparks, following one another at very short intervals of time, each
making a mark on the paper or other sheet receiving the impression or per-
foration. In using this part of my Invention, I prefer to cause a strip of
paper sensitive to photographic action, or otherwise, to travel with a steady
motion across the path of the end of the indicator over a metal plate,above which
plate the end of a conductor projecting from, or forming part of the indicator,
moves to and fro in consequence of the action of the current transmitting
signals. The series of sparks excited by the Ruhmkorff coil or other instru.
ment takes place between the before-mentioned end of a conductor and the

page_text: metal plate, and makes a series of marks on the paper either by photographic
action or perforation, or both. The result is an undulating curve of dots, the
character and succession of the undulations ofwhich give the different signals
desired to be sent.
:
Thirteenth Part.-I use an apparatus by means of which electric signals
may be read off by observing the amount, greater or less, of motion of an
indicator,and that, by observing the same directly, or by observing the motion'
of a spot of light reflected from a mirror carried by the indicator, and thrown
on a graduated screen, or received by a telescope, such greater or less amount
of motion being produced by currents of greater or less strength, regulated as
herein-after described. For this purpose I prefer to attach to the indicator a
very light mirror reflecting a beam of light, which beam produces a luminous
spot or line on a graduated screen, by the motions of which spot or line the
corresponding motions of the indicator are made visible.. It is useful to
employ a lens for concentrating and bringing to a focus the beam of light; in'
which case the screen should be at or near the focus of the lens. When I use
a lens for the before-mentioned purpose, I prefer that it should form part of
the casing by which the indicator is protected from currents of air; the
illuminating beam of light enters the casing through the lens, is reflected:
from the mirror, and leaves the casing through the lens again.
Figure 4
represents, on a scale somewhat larger than the actual scale, the indicator
which I prefer for a galvanometer with one thread, wire, or fibre ; A is a
cylinder of glass with glass ends; I usually make one or both ends of the form
of lenses; B, a small mirror hung by the fibre D, in the interior of the
cylinder; C, C, a small steel magnet or indicator fixed to the mirror; a'
small circular plate placed behind the indicator and moved backwards and'
forwards bya screw, forms an adjustable stop for checking its oscillations and
limiting the range. Figure 5 represents, on a scale about one-quarter of the
actual dimensions, one of the galvanometers which I use. A is the bobbin
with its coil of conducting wire fixed upon a stand, which has levelling screws;
B. B, B, B, B, B, B, studs connected with the coil at different points, so as
to enable the operator to send the electric current to be measured through
different lengths of coil, accordingto the sensibility required in the instrument;
C,central aperture in the bobbin,intowhich is inserted the cylinder containing
the indicator represented in Figure 4; D, E, handles for adjusting the
position of a fixed magnet, which is concealed beneath the stand of the
galvanometer, and which regulates the stability of the indicator. One of these
handles turns a tangent screw which drives a horizontal pinion so as to turn'

page_text: the magnet into any required direction; the other handle turns a vertical
pinion which works into a vertical rack, so as to place the magnet at any
required depth belowthe bobbin. Figure 6 represents another of the galvano-
meters which I use. A, bobbin with the coil for the current to be measured;
C, opening, containing the magnet or indicator with its mirror as before;
B, B, a pair of bobbins with the coil, through which a constant current is
transmitted. The axis of this coil is perpendicular to that of the coil A;
when no current traverses the coil A the indicator places itself along the axis
of B, B; when a current traverses the coil A the indicator deviates through
an angle depending on the strength of this current; D, pinion, and E, clamp
screw for adjusting the angular positions of the coils B, B, and A; the
adjusting coil B, B, will be again referred to under the head of the twentieth
part of my Invention.
Fourteenth Part.-In long lines of submarine telegraph, I use apparatus
by which, for a single signal, an electric current of a stated strength is as
rapidly instituted in a telegraph wire as possible, and maintained as nearly
as possible at the stated strength until an indication is taken from it by any
of the receivinginstruments,galvanometers, relays, or electrometers described
above, or by any other which may be convenient. The indication must be of
such a kind that from it, with due allowance for the electric condition of the
wire as affected by previous operations, it may be possible to estimate what
was the strength of current arranged for at the transmitting end. According
to the strength of current (positive or negative) thus estimated, one number
or another, one letter or another, one word or another,one piece of intelligence
or another, is read off according to a pre-arranged code. I.use a Daniell's or
other constant battery, or any other electromotor by which definite and
sufficientlyexact measured amounts of electro-motive force can be applied for
making electric signals of this kind. I use the following plan for making
the current as rapidly as possible approach the stated strength for anysignal,
and that whatsoever may have been the strength employed in the signal
immediately preceding it or in any of the preceding signals:-When thewire
is unelectrified to begin with, then I apply first a stronger electro-motive force
than that required to maintain the current at the stated strength for a short
time, and after that I apply the electro-motive force just required to maintain
a current at the stated strength, and continue such application until the time
comes to make the next signal; I next apply, for a short time,an electro-motive
force, differing from the last by a greater amount than that by which the
electro-motive force corresponding to the new sigual differs from it,afterwhich

page_text: 'he electro-motive force simply required to maintain the stated strength corre-
sponding to the new signal is applied, and held on until it is time to commence
a third signal, and so on.
I also, in some cases, use the following plan :-I apply constant battery
power during a certain measured interval of time, then another battery power
during another equal interval of time, and so on, these degrees of power, equal
or unequal, as the case may be, being each determined by calculation or
otherwise, so as to compensate so far as is required the residual effects of
preceding operations, and at the same time to produce a new effect constituting
or contributing towards a new signal..
The method of performing this and similar operations will be best under-
stood by an example such as the following:-To get a letter every three
seconds, I apply, by means of a pendulum and clockwork apparatus during
one second, a certain strength, say forty-eight, of positive electro-motive force,
during the next second fifty of negative electro-motive force, during the third
second twelve of positive electro-motive force. The effect at the receiving end
of a certain length of line is to make the indicator move to a positivemaximum
of deflection corresponding to the letter required, and fall back to zero or
nearly to zero before it commences to indicate the effect of a similar succession
of operations made for another letter during the next three seconds. The
proportionate strengths for different simple signals are the same for the same
line of telegraph and speed of working, the absolute strengths alone being
different. For different lines of telegraph, and different speeds of working,
the proper proportions of the electro-motive forces in each case can best be
found by experiment on the line itself.
In order to illustrate this part of my Invention, Figure 9 represents appa-
ratus which I use in carrying it into effect, on a scale of about one-half of the
actual dimensions. In order to render that Figure as easily intelligible as
possible, I have simplified it in cases in which several parts or sets of parts
of the apparatus are exactly similar to each other in construction and use, by
shewing only one such part or set of parts; 1. have also omitted such ordinary
and well-known details of mechanism and framework as any instrument
maker can easily supply, and can vary at his discretion, because such details
would complicate the Drawing, and conceal the essential features of the
Invention which it illustrates. I wish it also to be understood that every
conductor represented in the Drawing is insulated by the ordinary means of
insulation from all electrical communication with other bodies, except such
communications as are specially mentioned in the description.
A, and A, A2 and As, A, and A., are three pairs of wires, connected with a

page_text: galvanic battery (not shewn) at such three pairs of points as are suitable for
producing the three successive currents required for making a certain given
signal, As, A2, A₁, being the three conductors which, in order to produce that
signal, are successively to be connected with the line wire, and A6, A5, A4,
those which are successively to be connected with the earth; these six wires
are respectively connected with six studs B₁, B2, B3, B4, B5, B6, fixed on a
board underneath a key D; C₁, C2, C3, C4, C5, C6, are six springs, which are
brought into contact with the respective studs when the key is depressed, and
which rise and break contact when the key is not held down; the key turns
on a rod at E; there are as many keys, each with its six wires, six studs,
and six springs, as there are distinct simple signals in the code of signals,
but, according to the principle already stated, only one key with its adjuncts
is shewn. F is an arbor made to rotate by clockwork; the motion of the
clockwork is regulated by a pendulum and a dead-beat escapement; I have
hitherto used a pendulum beating seconds; the arbor F makes one revo-
lution consisting of twenty-four beats or jumps for each twenty-four swings of
the pendulum. G is a circular cam having four equidistant teeth. H is a
lever which is lifted and dropped once in every six beats by the teeth of the
cam. J, a fixed stud to which is attached a spring for holding H down when
not lifted by a tooth; for this spring a weight might be substituted. I, an
arbor carrying the lever H, and also another lever K, which passes at L
through an opening or slot in the key D; in that slot is seen a cross bar
fixed to the key, and under the cross bar is a pin projecting from the lever K,
and each key in the row of keys is provided with a similar lever, pin, and
cross bar; when the lever H is not lifted, the pins projecting from the
lever K, being below the cross bars of the keys, lock the keys and prevent
their being depressed; when the lever H is lifted, the pins.are all drawn
back, and all the keys of the row are unlocked at once for an instant, and
then locked again. Should the clerk using the instrument press upon any
key it descends at the instant of unlocking, and when the keys are again
locked the pin is above instead of below the cross bar of the depressed key,
so that that key is held down, and the contact of its springs and studs
maintained until the next unlocking; that is, for six beats of the clockwork.
M₁, M,, M., M., M5, M., are six wires respectively connecting the six key
springs C₁, C2, C3, C4, C5, C, with six springs N₁, N2, N3, N4, N, N., which
I call first cam springs. There is only one set of six first cam springs for the
whole of the keys in a row; all the key springs corresponding to the springs
C₁ for the several keys being connected with the single cam spring N₁, all the
key springs corresponding to C₂ with the single cam spring N₁, and so on

page_text: The three cam springs N₁, N, N₁, are made to communicate successively..
with the line wire at the same instants that the other three cam springs
No, N., N, are made to communicate successively with the earth by means;
presently to be described. P1, P2, P3, P4, are four cams carried by the arbor
F, which I call respectively P₁, P3, the line cams, and P2, P, the earth cams.
Each of those cams is insulated from the arbor, and each consists of two discs.
of different diameters. The smaller discs are circular, and are always in
contact respectively with the springs Q1, Q. Q3, Q₁, which I call the second.
cam springs. Each of the larger discs has four similar equidistant projections,
whose outer surfaces are portions of one cylinder, and each of those pro-
jections occupies a little less than one-twelfth part of the circumference of the
disc. The positions of the cains on the arbor and those of the ends of the six
first cam springs, are so adjusted that, when the arbor, rotates, the projections
of the two pairs of cams come into contact successively with the ends of the
three pairs of first. cam springs in the following order; that is to say, imme-
diately on the unlocking of the keys the pair of first cam springs N3, No, are.
brought into communication with the cams P1, P2, and through them with
the pair of second cam springs Q1, Q2; next, the pair of first cam springs:
N, N, are brought into communication with the pair of cams P. P₁, and
through them with the pair, of second cam springs Q3, Q₁; and, lastly, the
pair of first cam springs N₁, N., are brought into communication with the pair
of cams P1, P2, and through them with the pair of second cam springs Q1, Q2,
and so on in rotation. The second cam springs Q1 Q2 Q3 Q4, communicate:
respectively by wires R₁; R2, R3, R₁, with two pairs of studs S₁, S2, S3, S.
U is part of the rod of the pendulum, which regulates the motion of the:
clockwork. T1, T2, are a pair of flat springs, which I call the pendulum
springs, insulated from each other, and fixed across the pendulum rod, by
which they are carried. T, communicates through an extensible conductor
V. with. the line wire, and T, communicates through an extensible conductor
V₁ with the earth. When the pendulum is to the right of the vertical posi-
tion the springs T₁, T₂, are in contact with the studs S₁, S2; when the
pendulum is to the left of the vertical position the springs T₁, T2, are in
contact with the studs S, S₁; when the pendulum is in the act of passing
the vertical ahe springs T1, T2, are not in contact with any of those studs.
The effect of this is, that, during the second half of each swing of the pen-
dulum towards. the right, and during the first half of each swing towards the
left, the line cam P, communicates through Q₁, R₁, S₁, T₁, and V₁ with the
line wire; and the earth cam P, communicates through Q2, R2, S₂, T₂, and V₂

page_text: with the earth; and that during the second half of each swing towards the
left, and the first half of each swing towards the right, the line cam P, com-
municates through Q, R, S, T₁, and V, with the line wire; and the earth
cam P, communicates through Q, R, S, T₂, and V₂ with the earth. The
combined effect of the whole apparatus is this:-When the clerk presses on
a given key the locking and unlocking apparatus allows the key to descend
at a certain instant, and holds it down for six beats of the clockwork, in the
course of which time the six key springs and their studs maintain two portions
of each of the three circuits required for the three currents proper to produce
the signal wanted. By the action of the three pairs of first cam springs, and
of the two line cams and two earth cams, two other portions of each of those
three circuits are maintained for the three circuits successively.
By the
action of the pendulum and its springs each circuit is completed in succession,
and maintained complete during a definite interval of time, being that of two
half swings of the pendulum; that is to say, one second. I prefer to have
a second row of keys on the same instrument; in that case, either by suit-
ably placing the locking and unlocking lever of the second row corresponding
to H, or by having a second cam corresponding to G, I cause the second row
of keys to be unlocked at the instants exactly midway between the instants
at which the first row of keys is unlocked. I have also a second set of first
cam springs, corresponding to those marked N₁, &c., for the second row of
keys, which springs in the Figure are marked N, and numbered from 7 to 12,
and the wires which connect them with the key springs of the second row are
marked M, and numbered from 7 to 12 also, but the second row of keys is
not shewn. The contacts for making the circuits through the pairs of springs
numbered 9 and 12, 8 and 11, 7 and 10, take place in succession during the
interval following that which is occupied by the contacts for making the
circuits belonging to the first row of keys. The two rows of keys may be
used either to give a more rapid succession and a greater variety of signals
than one row can conveniently produce, or to enable two clerks to work at
the same time according to the method already described under the head
of the eleventh part of my Invention. Although I have now described an
instrument regulated by clockwork for carrying into effect the fourteenth part
of my Invention, I wish it to be understood that that part of my Invention is
also capable of being carried into effect, and that I sometimes do carry it into
effect by instruments in which the duration of each current is regulated by
hand, the clerk or operator having a metronome, a clock beating rapidly, or
other suitable instrument near him to regulate his estimation of time; and for

page_text: that purpose I have a set of keys, each of which while depressed causes a
certain fixed amount of electro-motive force to be applied to the telegraph
wire; and to make a given signal, a certain specified pair or set of keys are
depressed in a specified order, during specified intervals of time determined by
experiment and calculation, as herein-before stated. One convenient arrange-
ment is as follows:-There are two rows of keys,an upper and a lower, each
containing the same number of keys. Each key of the upper row being
depressed maintains a certain amount of electro-motive force in the telegraph
wire, and the key immediately below in the lower row maintains the same
force in the opposite direction. When none of the keys are depressed the
telegraph wire is connected with the earth. To make a current in a given
direction at the remote end of a long line of telegraph wire, which shall rise
rapidly to a stated strength, and then fall rapidly to zero, or nearly so, an.
electro-motive force of a given amount is to be applied at the near end, first
in the direction of the desired current for a certain time, and then an equal
electro-motive force is to be applied in the opposite direction for a certain
time of less duration than the first, the proper intervals of time being sensibly
the same for all required strengths of current to be produced at the remote
end are found, once for all, by experiment. A more accurate mode of securing
that the different electro-motive forces are applied for the proper intervals of
time, which I also use, is to make and break the contacts by means of a pen-
dulum, so constructed as to swing on one side of its point of rest in a different
time from that in which it swings on the other side, these two times being
arranged so as to be the times for applying the two different forces. I also
attain the same object by using a wheel moved by clockwork or other motive
power giving a regulated motion, or moved by hand and regulated by a fly
wheel or governor, and having cams adjusted so as to make and break contact
at the proper intervals.
Fifteenth Part. When it is desired to work through a submarine line, or
through a very long air liue, in both directions at once, then, in order to avoid
the comparatively violent action which is caused in the receiving instrument
at the transmitting end, by transmitting signals from that end through it, I
throw the receiving instrument at the transmitting end out of circuit during
certain parts of the time during which a signal is being transmitted from that
end. I regulate the time during which the signal is transmitted by such
arrangements of wheels and cams as before described, and by a separate wheel
on the same arbor with proper cams I regulate the times during which the
receiving instrument is thrown out of circuit.

page_text: Sixteenth Part. I compensate the effects produced by currents transmitted
from one end on the indicator of the receiving instrument at that end, so that
the indications of that instrument are either not sensibly affected by them, or
that the indications it would have given had it not been affected by them may
be estimated. 1 produce that compensation by sending, while the receiving
instrument at the transmitting end is in circuit, a current through a compen-
sating coil near it, that compensating current acting upon the indicator of
the receiving instrument at the transmitting end, at the same time that it is
acted upon by the principal current of transmission, but in an opposite
direction. The compensating current is not necessarily of the same strength
with the current of transmission, but may be stronger or weaker in any pro-
portion, according to the length, form, and position of the compensating coil,
its stength being regulated so as to compensate the effect of the current of
transmission. Thus I dispense with the resistance coil used to equalize the
strength of the two currents in previous apparatus for the same purpose; the
proper strength, and the proper law of variation of the strength of the com-
pensating current are found by experiment, and the compensating current is
produced, and its strength regulated, by a mechanical motion put into action
by the depression of the same key which produced the principal current. 1
also compensate the effect of the current of transmission on the indicator of
the receiving instrument by a magnet properly adjusted as to position,
strength, and motion; these adjustments to be determined by trial. The kind
of magnet most suitable for the purpose is an electro-magnet, consisting of a
coil of wire, the strength of current through which will correspond to the
electro-motive force causing the current of transmission; and one mode of
mounting this electro-magnet is by attaching it to a wheel rotating ouce in
the period of a single complete signal, the position of the magnet on which
wheel is to be found by trial, so as to make the compensation most perfect.
Seventeenth Part.-In working in both directions at once, I make each
electric signal as nearly as possible simultaneously at the two ends, or
alternately at definite intervals of time; and for that purpose, I use a
mechanical apparatus at each end, regulated according to an independent
clock, or worked by clockwork, and I have electric comparisons of time
between the two ends made as frequently as is necessary to make the
mechanisms at the two ends keep time with one another as accurately as is
required.
Eighteenth Part.-I use, when convenient or when desired for any object,
two or more different galvanometers or other receiving instruments, either

page_text: each self-recording, or each read off by one or more observers, or all read off
by one observer, but thrown into circuit in connection with the telegraph wire
during intervals regulated by the same mechanism for keeping time as that
which is used in making the signals, and which I have already described under
the head of the fourteenth part of my Invention.
"
I do not proceed with that which is called in my Provisional Specification
the nineteenth part of my Invention, and which is therein described in the
following words, that is to say," For checking the motion of any moveable
"indicator in a receiving instrument after its indication has been read off, I
'propose to use a magnet moved by mechanism, or a vessel of liquid brought
"up so as to cover part of the moveable body,and removed again if necessary
"when a new indication is to be taken, or by turning or otherwise moving the
"filaments or wires by which the body is supported, when it is so supported,
"or by other suitable methods."
Twentieth Part. For increasing, diminishing, or regulating to any desired
degree the stability of the indicator of a galvanometer, or galvanometric relay,
or of any instrument used in telegraphing, having a moveable indicator, I use
wires conveying currents of electricity. The form of such wires may be varied,.
but I prefer coils in planes perpendicular to the position of equilibrium of the
magnetic axis of the indicator,and I adjust the strength of the current in such
coils, so as to produce the degree of stability which may be convenient. Such
adjusting coils as are now described have aiready been mentioned under the
head of the third part of my Invention, and are illustrated in Figure 6.
In my Provisional Specification the nature of the twenty-first part of my
Invention is stated as follows:-"In the use of galvanometers, or galvanometric
"relays, or of any other kind of relay or receiving instrument, I propose, in
"order to compensate the effect of electrification of the telegraph wire
"remaining over from previous signals, to use in the neighbourhood of the
"moveable indicating body an electro-magnet or coil of wire conveying a
"current instituted and regulated to produce the desired effect, or a steel or
"other magnet, moved so as to produce the desired effect.
When it is not
convenient to make allowance for such residual effects from previous signals
by calculation or otherwise, and when they are of such an amount as to
" exercise a sensible disturbance if not compensated, I propose to use similar
"apparatus, under similar conditions, in sending messages through either a
"land or a submarine line, in both directions at once for the purpose of com-
pensating the effect on any receiving instrument due to signals transmitted
"in the direction contrary to that from which the signals to receive which it
$$

page_text: "is employed are coming;" but so far as I use and intend to proceed with that
part of my Invention it is comprehended under the sixteenth part of my Inven-
tion, and the manner in which it is to be performed is herein-before described.
Twenty-second Part.-I use two mirrors attached to the indicators of two
galvanometers, at the receiving end of, and receiving currents from one
transmitting station by two separate telegraph lines; and I cause a ray of
light to be reflected from these two mirrors in succession, and to be thrown
on a screen, so as to give a visible effect, or by photographic or thermal
influence, a recorded effect, by which any lines, figures, letters or symbols,
drawn or written at the transmitting station upon an instrument adapted to
give different degrees of electro-motive force to the two lines, according to the
two independent variables thus dealt with may be written, drawn, or made
visible at the receiving station. For transmitting a line, drawing, or writing
of any kind by telegraph, I add a third telegraph wire, which is so connected
and arranged, that when the tracing point at the transmitting station is lifted
from the surface on which the curve is drawn, the indicating or marking
beam of light is cut off at the receiving station. The manner of performing
this part of my Invention may be varied in its details, but one method is as
follows I prefer that the tracing point at the transmitting station should
move on a horizontal plane. To fix the ideas, I distinguish the two com-
ponents of the motion of the tracing oint, as the north and south component,
and the east and west component.. A row of studs, running north and south,
are connected with different points in a battery,so as to give a series of electro-
motive forces of graduated strengths. A conductor, by means of a parallel
motion, accompanies the tracing point in its north and south motion, and by
touching one or other of the row of studs, establishes a current in one of the
line wires, of a strength suitable to cause one of the mirrors at the receiving
station to takean angular position,corresponding to the deviation ofthe tracing
point to the north or south of its middle position. Another row of studs.running
east and west, is connected with different points in another battery, so as to
give a series of currents of graduated strengths. A conductor, by means of a
parallel motion, accompanies the tracing point in its east and west motion,
and, by touching one or other of the second row of studs, establishes a current
in the second line wire of a strength suitable to cause the second mirror
at the receiving station to take an angular position corresponding to the
deviation of the tracing point to the east or west of its middle position. A ray,
reflected successively from the two mirrors, performs motions sensibly similar
to those of the tracing point. There is a screen which intercepts the beam

page_text: unless drawn back by an electro-magnet. That magnet is made to act by a
current traversing the third line wire, and part of the circuit conveying that
current is formed by the tracing point and by a metal plate on which it is
moved, so that. by lifting the tracing point the beam is intercepted.
In using every part of my Invention the details may be varied without
departing from the principle of the Invention.
1 do not claim the mechanical movements and other elementary parts of
the apparatus herein-before described otherwise than as herein-after men-
tioned; but what I do claim is, that which is stated or referred to in the
following statement, that is to say :-
In connection with the first part of my Invention, I claim the method of
testing a telegraph conductor by the aid of electrostatic instruments in the
manner herein-before described. I also claim the electrometer first herein-
before described, so far as regards the use of a testing conductor, consisting of
two or more parts, so formed and arranged that when all are electrified to the
same potential, they shall have no directive effect on the indicator; and so faras
regards the use, in combination with such a testing conductor, of an indicator
ndependently charged to and maintained at a high potential; and I claim
such instrument for all purposes connected with the testing, either in the
course of manufacture or afterwards, or in the working of electric tele-
graphs, in which term I include all telegraphs worked by electricity, in
whatever way such electricity is excited; and also so far as any of the other
arrangements of the first mentioned electrometer are comprised in any other
part of
claim.
my
I also claim the electrometer secondly herein-before described, so far as
regards the use of the drum herein-before described enclosing the indicator, and
also so far as regards the connecting the indicator with the earth, and insu-
lating the drum, and connecting it with the conductor to be tested.
In connection with the second part of my Invention, I claim the method of
testing the insulation of a telegraph wire therein described.
.
In connection with the third part of my Invention, I claim the marine galva-
nometers herein-before described, so far as regards the suspension of the
indicator by a stretched fibre passing through its centre of gravity, and so far
as any other parts of the arrangement are comprised in any other part of my
claim.
In connection with the fourth part of my Invention, I claim the double
bifilar suspension for indicators herein-before described.
In connection with the fourth and fifth parts of my Invention, I claim the

page_text: useofa suspending or supporting filament or filaments of the indicator of any
of the instruments herein-before mentioned, as part of a conducting circuit
connecting the indicator with another conductor. I also claim the use, for
the same purpose, of a conductor dipping into a conducting liquid, in con-
nection with the first and fifth parts of my Invention, and as described in the
part of this Specification wherein those parts of my Invention are described.
I do not claim the use of conducting filaments, or of conducting liquids, except
in telegraphic apparatus.
In connection with the sixth part of my Invention, I claim the use for the
indicator of a receiving instrument of two magnets, acted on either by the
same coil or by different coils in circuit with the line, one of which magnets is
deflected by a positive current, and is prevented by stops from being deflected
bya negative current, and the other of which is deflected by a negative current,
and is prevented by stops from being deflected by a positive current, and
which indicators are kept in their mean position by any of the modes described
in this Specification, or by any equivalent modes. And I also claim the use
of two or more pairs of such indicators, whether kept in their mean positions
by any of the modes herein-before described, or by any other mode, so
arranged that the number of indicators in motion by one current, depends
on and is regulated by a regulated degree of strength of the transmitted
current.
In connection with the seventh part of my Invention, I claim the use of
secondary indicators to indicate, receive, record, or transmit signals, depending
on the motions of primary magnets or indicators, in the manner herein-before
described.
In connection with the eighth part of my Invention, I claim the use of
electrometers as receiving instruments for telegraphic signals made by elec-
tricity other than frictional.
In connection with the ninth part of my Invention, I claim the use of the
thermal effects of rays reflected from the indicator, in manner herein-before
described, for the purpose of receiving, recording, or transmitting telegraphic
signals.
In connection with the tenth part of my Invention, I claim the use of
photography, in manner herein-before described, for receiving and recording
telegraphic signals.
In connection with the eleventh part of my Invention, I claim the method
herein-before described of transmitting messages between one or more con-
ductors and a different number of conductors, and also the method herein-

page_text: before described, by which two or more messages can be sent at the same time
from the same station along one telegraph wire.
In connection with the twelfth part of my Invention, I claim the use of
electric sparks, in manner herein-before described, for receiving or recording
telegraphic signals by means of marks, impressions, chemical changes, or per-
forations produced by these sparks.
In connection with the thirteenth part of my Invention, I claim the use
of a transmitting instrument, adapted to send currents of various measured
strengths, combined with a receiving instrument, adapted for receiving and
recording the deflections of the indicator caused by the different strengths of
current, and for giving a variety of signals thereby.
In connection with the fourteenth part of my Invention, I claim the methods
and apparatus herein-before described for rapidly producing and for main-
taining electric currents of stated strengths in telegraphic wires, and for dis-
charging currents from such wires.
In connection with the fifteenth part of my Invention, 1 claim the arrange-
ments for throwing the receiving instrument at the transmitting end out of
circuit during part of the time during which a signal is being transmitted
from that end, in the manner and for the purposes herein-before described.
In connection with the sixteenth part of my Invention, I claim the com-
pensating the effects produced on the receiving instrument at the transmitting
end by operations performed at that station by means of such a compensating
current or moveable magnet as herein-before described.
In connection with the seventeenth part of my Invention, I claim the method
herein-before described of transmitting signals in opposite directions at the
same time along the same telegraph wire by working at regulated instants
of time.
In connection with the eighteenth part of my Invention, I claim the use, for
receiving and recording signals, of two or more instruments at or near the
same station, thrown into operation during regulated intervals of time.
In connection with the so-called nineteenth part of my Invention, I claim
10thing.
In connection with the twentieth part of my Invention, I claim the method
and apparatus herein-before described for increasing, diminishing, or regu-
ating the stability of a moveable magnet.
In connection with the twenty-first part of my Invention, I claim nothing
eyond what has already been claimed in connection with the sixteenth part
f my Invention.

page_text: In connection with the twenty-second part of my Invention, I claim the
method and apparatus herein-before described for producing, at a receiving
station, lines, figures, letters, or symbols of given shapes.
In witness whereof, I, the said William Thomson, have hereunto set my
hand and seal, this Nineteenth day of August, in the year of our Lord
One thousand eight hundred and fifty-eight.
WILLIAM THOMSON. (L.B.)

page_text: DISCLAIMER AND MEMORANDUM OF ALTERATION as proposed to be
entered by Sir WILLIAM THOMSON, Doctor of Laws, Professor of
Natural Philosophy, in the University and College of Glasgow,
in the County of Lanark, pursuant to the Statutes in that case made
and provided.
WHEREAS Her Majesty Queen Victoria, by Her Letters Patent,
under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster the Twentieth day of February
One thousand eight hundred and fifty-eight, in the twenty-first year
of Her reign, did give and grant unto the said William Thomson, his
executors, administrators, and assigns, the sole privilege of making,
using, exercising, and vending the said Invention of "IMPROVEMENTS IN
TESTING AND WORKING ELECTRIC TELEGRAPHS" within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, for
and during the term of fourteen years thence next ensuing: And whereas
A

page_text: in pursuance of a proviso in the said Letters Patent contained the said
William Thomson, did within six calendar months next after the date
of the said Letters Patent cause a Specification in writing under his
hand and seal, purporting to describe and ascertain the nature of the
said Invention and in what manner the same was to be performed, to be
duly filed in the Great Seal Patent Office: And whereas since filing
the said Specification, I, the said William Thomson, have discovered
that the said Invention is not ascertained and described with sufficient
precision and that some of the claiming clauses contained in the said
Specification are too wide and indefinite and claim more than I intended
to claim and am desirous of claiming.
seventy-one
Now in consequence thereof, I, the said William Thomson, am desirous
of limiting the said claiming clauses, and of disclaiming, altering, and
amending, and do hereby disclaim, alter, and amend the said Specification
in manner following, that is to say, in the said Specification I strike
out in line 37 of page 15 of the Queen's Printers' copy thereof published
in One thousand cight hundred and fifty-eight, the words "of a tangent
galvanometer or other galvanometer or." Also in line 28 of page 18
of the said printed copy, I insert after the words "sixth part" the words
"is disclaimed" and I strike out the words "I use electro motive,"
and the following words down to and including the word "apparatus"
in line 12 of page 19. Also in line 38 of page 20 of the said printed
copy I insert after the words "tenth part" the words "is disclaimed "
and I strike out the words "I use" and following words down to and
including the words "sensitive substance" in line 7 of page 21. Also
in line 8 of page 21 of the said printed copy I insert after the words
eleventh part the words "is disclaimed," and I strike out the words "I
use a relay" and following words down to and including the words
part of my Invention" in line 21 of page 22. Also in line 23 of
page 23 of the said printed I substitute for the word "glass" the
word "brass." Also in line 29 of page 30 of the said printed copy,
I insert after the words "seventeenth part" the words "is disclaimed
and I strike out the words "in working" and the following words
down to and including the word "required" in line 36 of the same
page 30. Also in line 37 of the same page 30 I insert after the words
"eighteenth parti
the words "is disclaimed" and I strike out the
convenient" and following words down to, and
words "I use when
including the words
"
_copy
^
part of my Invention" in line 5 of page 31.

page_text: Also in line 12 of page 33 of the said printed copy, I insert after the
words "by the aid of " the words "the above described." Also in line 9 of
page 34 of the said printed copy I strike out the words "in connection
with the sixth part" and the following words down to and including
the word "current" in line 21 of the same page 34. Also before the
word "electrometers" in line 27 of the same page 34 I insert the words
"the above described." Also in line 33 of the same page 34 I strike
out the words "in connection with the tenth part" and following words
down to and including the words " telegraphic signals" in line 35 of
the same page 34. Also in line 36 of the same page 34, I strike out the
words "in connection with the eleventh part" and following words
down to and including the words "telegraph wire" in the following
page 35. Also in line 5 of page 35 of the said printed copy I insert
before the words "telegraphic signals " the word "the" and after
those same words the words "herein described," which will then precede
the words "by means of sparks." Also in line 9 of the same page 35
I substitute for the words "with a," the words "with the" before the
words "receiving instrument," and after the last mentioned words I
insert the words "constructed as herein described and." Also in line 24
of the same page 35 I strike out the words "in connection with the
seventeenth" and following words down to and including the words "of
time" in line 27 of the same page 35. Also in linė 28 of the same
page 35 I strike out the words "in connection with the eighteenth part"
and following words down to and including the words "intervals of
time" in line 30 of the same page 35, and my said Specification when
altered by me as above proposed will read as follows :-
NOW KNOW YE, that I, the said William Thomson, 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 (reference being had to the Drawings
annexed), that is to say :-
For the sake of distinctness I have divided the description of the said
Invention into several parts, that is to say
Part First. I test the insulation of a telegraphic wire by communicating
a charge of electricity to it, and then leaving it with both ends insulated
and some part of it connected (and when I use the term "connected"
here and throughout the Specification I mean unless otherwise expressed
connected by a wire or other conductor of electricity) with an instru

page_text: that the
ment for measuring electrostatic potential and leaving it so connected
and observing the diminution of its potential in a certain time.
"Potential" is a term the mathematical definition of which is well
known to all persons conversant with the mathematical theories of
electricity, magnetism, and attracting forces generally; for the present
purpose it is sufficient to say "electrostatic potential," or as I shall call
it for shortness simply the " potential," for any point A in space is
a quantity depending on the position and electrical state of all the
bodies which act at the point A (being in strictness all the bodies in
the universe, but with sufficient accuracy for the present purpose all the
electrified bodies in the neighbourhood of A), and such that the difference
between the values of the potential at the point A and the potential at
any other point. B is a measure of the tendency of electricity to flow
from A to B, or vice versa, supposing A and B connected by a small
conducting wire. It follows from this that where there is equilibrium
the potential at every point of an electrified insulated conducting body
including every other insulated conducting body connected with the
first by wires or other conductors is the same, and may be measured by
connecting by a conducting wire any part of the conducting body with
insulated electrometer of sufficient delicacy.
any
For measuring the potential I use any suitable electrometer. Electro-
meters hitherto in use, such as the gold leaf or the pith ball electro-
meter are not sufficiently sensitive to measure the potential which can
be conveniently communicated to a telegraph wire, I therefore use one
of those next described. One of the electrometers which I use and
which from its indications depending on the potential of the indicator
as well as on the difference of potentials to be measured may be called
the heterostatic electrometer consists of the following parts:-
1. A testing conductor which consists of two, four, or any even
number of separate pieces of metal, but which may be most easily
described by first supposing them to form one piece, and then describing
how that piece is to be divided. The testing conductor then consists
of a piece of metal turned to the form of a true solid of revolution of
such a shape that when the indicator, herein-after described, turns about
the axis of figure-of the solid the end of the indicator may be exposed
to the action of as large a part as conveniently may be of the testing
conductor. Thus the testing conductor may be, as shewn in the Figure
a flat circular ring placed horizontally, or it may be a circular plate

page_text: placed horizontally, the end of the indicator in either case moving
just over the upper surface of the testing conducting, or it may be a
cylindrical ring with its axis of figure vertical, the end of the indicator
then moving just inside the ring, or it may be such a flat circular ring
or plate surrounded with such a cylindrical ring so as to be of the shape
of a shallow compass bowl, the end of the indicator then moving as the
end of the ordinary compass needle, or it may be of the shape last
described with the addition of a flat circular ring placed above the
indicator, some additional contrivance, which may be easily arranged,
being then made to allow the position of the indicator to be observed.
This testing conductor is to be divided into two, four, six, or any even
number of equal sectors by slits at the intersections with it of planes
passing through the axis of figure and the sectors separated from each
other by the smallest possible interval that will prevent actual contact,
the thickness of a sheet of paper will be sufficient if the instrument be
well made and carefully adjusted. It will be convenient first to describe
the instrument and mode of using it when the testing conductor
is divided into two sectors, and then to describe the variations caused
by dividing the testing conductor into four or more sectors.
the
^
2. An indicator. By the term "indicator" I mean here and in the
following part of the Specification a body acted on by the forces required
to be measured and suspended or supported in such a way as by its
angular motion to measure or indicate the amount or change of those
forces. The particular form and construction of the indicator in each
case will be described. In the instrument now describing the indicator
consists of a thin conducting slip of metal suspended at one end by
non-conducting filament and kept horizontal by a counterpoise, and
kept at a constant or sensibly constant potential by means of the
conductor next described.
3. A conductor connecting the indicator with a body of large electrical
apacity kept electrified to a constant potential, the difference of which
rom the potential of either of the bodies the difference of whose
otential is to be measured is very large compared with the last-mentioned
ifference.
4. A conductor to connect one of the parts of the testing conductor
ith the telegraphic wire to be tested, and another conductor to connect
he other part of the testing conductor with the earth, or with another
art of the telegraphic wire or any other body, the difference of potential

page_text: measured.
5. A case or cases to enclose the parts herein-before described with
an atmosphere artificially dried to preserve the indicator from dis-
turbances by currents of air or otherwise, and to maintain good insulation
in the various parts in which insulation is required.
6. A graduated scale or other arrangement for allowing the position
of the indicator to be observed at any time.
electrified
The principle of the action of the instrument is the following:-When
both parts of the testing conductor are in connection with one another,
or otherwise electrifried to the same potential they do not disturb or
affect the position of the indicator, and this by virtue of the shape of
the testing conductor, being that of a solid of revolution, having its
axis of figure coincident with the axis of motion of the indicator. If
it were of any other shape there would be an inductive effect between it
and the electrified indicator, which would give the indicator a tendency
to point in particular directions. The indicator is now to be adjusted by
the torsion head, so that its end rests immediately over or opposite onc
of the slits. This having been done, when the two parts of the testing
conductor are electrified to different potentials, the indicator deviates
to the side of that part the potential of which differs most from the
potential of the indicator.
By keeping the indicator electrified in
manner herein-before mentioned to a high potential, either positive or
negative, the effects of induction between the indicator and the testing
conductor are obviated and the sensibility of the instrument is greatly
increased, and we have the further advantage of being able to distinguish
by the direction in which the indicator moves, whether the potential
of the conductor tested or the difference of potentials of the two is
positive or negative, a result not given directly by an idiostatic electro-
meter, such as that next described. When we wish to measure the
difference of potential between two conductors, we bring one part of the
testing conductor into connection with one of the conductors, the other
into connection with the other, and observe the angular deflection of the
indicator; or we may turn the torsion head till the indicator is brought
back to its original position, and observe the amount of torsion required.
If one of the two conductors so tested is the earth, then as its potential
is considered as zero, we get a measure simply of the potential of the
other conductor.

page_text: In the instrument, as described, there is the disadvantage that the
indicator is subject on being highly electrified to be tilted down or
otherwise drawn into contact with the testing conductor and to be
discharged. This is obviated by dividing the testing conductor into
four equal sections, and connecting two opposite quadrants with the
conductor to be tested, the other two with the earth. The indicator
then is suspended by its centre, and made to extend equally in both
directions from the suspending filament, and the tendency to tilting or
to be otherwise drawn into contact with the testing conductor is obviated
and the power of the instrument doubled.
The testing conductor may be divided into six equal sectors, and
three alternate sectors connected with the conductor to be tested, and
the other three with the earth. In this case the indicator will be of
the form of a three-rayed star, the rays in the position of equilibrium
being immediately over or opposite alternate slits, and -in like manner
the testing conductor may be divided into eight or any number of
sectors, the indicator being in the form of a star with half as many rays
as there are sectors, but it is not probable that any increase above
four sectors will compensate for the increased expense and trouble in
construction and adjustment.
even
Λ
Figure 1 shews on, a scale of about one quarter of the actual dimen-
sions, one mode of constructing this electro-meter in its simplest form,
herein-before described. A, B, testing conductor, consisting of a flat
circular ring divided into two sectors by very narrow slits at C, C, and
having a scale marked on its upper surface. Each sector has an insulating
support or supports with three levelling screws to adjust it to a truly
horizontal plane and to a given elevation, permitting it also the requisite
horizontal motion, and steadied by springs, for which clamps may be
substituted. D, indicator, consisting of a flat thin slip of aluminium
or other suitable material with a counterpoise M. E, fibre of glass, or
other suitable material, by which the indicator is suspended with a
torsion head and graduated circle of the usual construction. F, con-
ductor connecting the indicator with the electrified body I, which
conductor may consist of a wire dipping into a cup containing a con-
ducting liquid. This mode of connection will be again mentioned under
the head of the fifth part of my Invention. G, conductor for connecting
one sector of the testing conductor with the conductor to be tested.
H, conductor for connecting the other sector of the testing conductor

page_text: with the earth, or the other conductor to be tested. I, electrified body,
which in the Figure is a Leyden jar charged to a high potential in the
usual way from an electrical machine, the conducting wire being in
connection with the internal coating of the jar, and the external coating
in connection with the earth. K, glass cylinder or other case con-
taining a dry atmosphere. L, conductor for charging and testing the
body I. N, vessel containing sulphuric acid or other absorbent material
for drying the air in the case.
For testing the insulation of the telegraph wire in cases in which it is
desired to give it a very high potential in testing it, and also for testing
the amount and permanency of the potential in the electrified body I part
of the heterostatic electrometer herein-before described, and generally
for measuring electrostatic potential where a less delicate measure is
required than that for which the first described electrometer is adapted,
I use an electrometer, which from its indications depending simply on
its own potential as communicated by connection with the bodies to be
tested may be called an idiostatic electrometer and which answers to the
following description :--
An indicator consisting of a. slip of metal suspended by its centre and
connected with two pieces of metal fixed near its ends and so arranged
that the indicator can swing freely in one direction in a horizontal plane,
and is stopped by the pieces of metal from swinging in the other. If this
combination be insulated and brought into connection with the electri-
fied conductor to be tested; whether its potential be positive or negative,
the indicator is deflected. By enclosing it in a hollow metallic cylinder
with metallic ends, herein-after referred to as the drum in contact with
the earth but not with the indicator, the deflection of the indicator is
increased and the indicator is at the same time protected from the effects
of irregular induction from surrounding bodies, and conversely if the
drum be insulated and connected with the electrified conductor to be
tested and the combination of pieces of metal and indicator be connected
with the earth a like amount of deflection of the indicator is produced.
idiostatic
Figure 2 shews on a scale of about one quarter of the actual dimen-
sions one mode of constructing this electrometer. A, vessel con-
taining sulphuric acid or other absorbent material to dry the air in the
air-tight case C, which stands on hollow pillars B, the interiors of which
make a communication between A and C; D, a cylindrical metallic drum

page_text: with its axis of figure vertical enclosed in the case C, and shewn by
dotted lines. This drum is supported by glass or other insulating
pillars which traverse the hollow pillars, and it has in the centre of its
upper and lower ends circular holes large enough to permit the tube F
to pass through without contact. E, insulated conductor, by which the
drum D can be connected with the body to be tested; F, vertical metal
tube capable of being turned into various positions about its vertical axis.
The position of this tube is indicated by an index attached to it which
points to a circular graduated scale on the top of the case C. The
vertical tube F traverses the case C and drum D; its construction within
the drum at the point marked H will be afterwards described. At I it
has or may have a glazed opening to permit the access of light to a
mirror, to be afterwards mentioned. G, torsion head, carrying a fibre or
wire which traverses the axis of the tube F, as shewn by a vertical dotted
line. From G down to H this fibre in the instruments I have con-
structed is of glass, but if a metallic wire sufficiently fine could be
procured I should prefer it, and in that case the wire below H and the
cup of conducting liquid afterwards mentioned might be dispensed with.
At H the wire or fibre carries the indicator to be afterwards mentioned.
From the indicator a wire goes down and communicates with the tube F
and with the earth by dipping into a small vessel of conducting liquid.
The deflection of the indicator is indicated either by the reflection of
light from a small mirror carried by this wire at I or by the position of a
very light index carried by it at K moving within a glass case and
pointing to a graduated one. Either or both of these methods may be
employed.
arc
Figure 3 is a horizontal section of the interior of the drum D near the
level of the point H; L is a horizontal section of the vertical tube F,
which here has two small openings in its opposite sides to allow of
the passage and motion of the indicator N, N; M, M, are two metallic
arms projecting from the tube at opposite edges of its two openings.
The indicator N, N, is of aluminium or other suitable metal and is
carried by the fibre or wire mentioned. When the electrical con-
dition of the apparatus is undisturbed the tube and the suspending
fibre or wire are to be adjusted until the indicator N, N, hangs nearly
in contact with the arms M, M. When the tube F and the indicator
are connected with the earth and the drum D with the conductor which
is to be tested, the bar N, N, is repelled by the arms M, M, and the
before

page_text: repulsive force measured by the deflection of the indicator or by the
torsion of the suspending fibre or wire required to bring back the
indicator to its original position measures the difference between
the potential of the conductor tested and of the carth.
This difference of potential may also be measured by connecting the
conductor to be tested with the tube and indicator, insulating them from
the earth and bringing the drum in connection with the carth, but this
mode of using the instrument I have found to be less convenient than
that first described. In this way too the difference of the potentials of
any two conductors may be measured.
Second Part. I also test the insulation of a telegraphic wire by
comparing its resistance to the flow of electricity from a constant source
with the resistance of a standard wire to the flow of electricity from the
same or another constant source.
A standard wire is one perfectly insulated and whose resistance to
electro-motive force is known and which resistance may be conveniently
expressed in terms of the resistance of a certain length of the telegraphic
wire to be tested if perfectly insulated. Several standard wires of
different resistances should be at hand to be used. One of the ways
in which I make the observation is by applying a batter to send a
current through the standard wire into the telegraph wire, insulated as
much as possible, and then to apply the electrodes of an electro-meter
such as either of those described, or of any other kind, first, to the two
ends of the standard wire, and next, to the end of the standard wire
which is connected with the telegraph wire to be tested and to the earth.
The resistance of the standard wire is to the resistance to be tested as
the difference of potentials at the two extremities of the standard wire
is to the difference between the potentials at the end of the standard
wire in connection with the telegraph wire and the earth.
Third Part. I test a submarine telegraph wire during the operation
of laying it by measuring from time to time the strength of currents
produced in it by the electro-motive force of a constant battery or
batteries, and that by means of various forms of galvanometer which
I have invented for the special purpose of being used at sea. The chicf
peculiarity of the different kinds of marine galvanometer which I have
invented consists in the moveable magnet, which is the indicator being
supported by means of one, two, three, or more threads, wires, or fibres,
in such a manner as to allow it the.requisite degree of freedom to move

page_text: and to give it the requisite degree of stability independently of gravity
and terrestrial magnetism, and in such a manner as to be as little as
possible disturbed by these forces, and by the reaction of its own inertia
against the inequalities of the ship's motion. When one thread wire
or fibre is used the indicator is fixed to the middle of and at right angles
to the thread, wire, or fibre, which should pass as nearly as possible
through the centre of gravity of the indicator. The thread, wire, or
fibre is tightened by screws and adjusted by torsion heads at both ends.
When two or four threads, wires, or fibres are used, then the mode
of support is that described in the fourth part of this Specification.
For the purpose of giving increased steadiness to the indicator I
sometimes use in addition to the mode of suspension herein-before
indicated a fixed magnet placed in a suitable position in its neighbour-
hood. By the word "magnet" I mean any body which exerts magnetic
force. The apparatus which I prefer for observing at any time the
angular deflection of the indicator is a mirror attached to that body
and reflecting a ray of light either after or before or after and before
the ray passes through one or more lenses, so as to be sent to and
brought to a focus at different parts of a graduated screen as the
indicator assumes different positions. The method of observing the
position of the indicator will again be referred to under the lead of
the thirteenth part of my Invention.
The frame of the galvanometer is fixed by screws to one end of a
board, at the other end of which is a lamp having a camphine or other
very brilliant flame for throwing a beam of light, and also a graduated
screen on which the beam reflected from the mirror is thrown, so as to
indicate the angular position of the indicator. The board is supported
from below by means of springs on a stand fixed to the ship. For this
purpose I prefer spiral springs of the kind known as furniture springs.
Round the stand and fixed to it is a rail from which springs or clastic
bands go to a rail fixed to the board, so as to moderate the horizontal
oscillation of the board and galvanometer.
Fourth Part. I use a double bifilar suspension for the indicator
in any electrometer, galvanometer, relay, or generally in any instru-
ment used for testing or for working electric telegraphs by means
of an indicator. This suspension I have invented to give any requisite
degree of stability or of instability to the indicator in any position of
equilibrium.

page_text: Figures 7 and 8 shew how this part of my Invention is performed.
In each of those Figures, G, H, represents the indicator, and AI, BK,
CI, DK, four fibres or wires by means of which the indicator is
attached to four points A, B, C, D. The dotted line L, M, is an
imaginary line perpendicular to the two lines A, B, C, D, which join
the points of suspension in pairs and also perpendicular or nearly so to
the plane in which the indicator moves. The dotted line E, F,
represents the position in which the indicator tends to place itself when
undisturbed, and the deviation of the indicator from that position, that
is, the angle between G, H, and E, F, indicates the direction and
amount of force derived from the arrangement by which the indicator
is acted on tending to make it return to or further diverge from its
position of equilibrium, according as the equilibrium is stable or unstable.
When A, B, is parallel to C, D, as in Figure 7, E, F, is also parallel to
A, B, and C, D; the equilibrium is then stable and the stability greatest.
As A, B, or C, D, or both are moved, so as not to be parallel, as in
Figure 8, the direction of E, F, is intermediate between the directions
of A, B, and C, D, and the stability is less than in the former case;
and the more the direction of A, B, differs from that of C, D, the less is
the stability until the directions of A, B, and C, D, differ by more than
one hundred and eighty degrees when (if the indicator is supported by
fibres having no sensible independent elasticity of torsion) the equi-
librium is unstable; and stops, at equal distances on each side of the
position of the equilibrium, are to be used to prevent the indicator
from diverging by more than a convenient angle from the position of
equilibrium. When the indicator is supported by wires having an
independent elasticity of torsion this elasticity increases the stability
or diminishes the instability which the indicator would otherwise have
from the mode of suspension; and a greater angular separation between
A, B, and C, D, must be used to give the same degree of stability and
instability as in the case of fibres without sensible elasticity of torsion.
The stability is adjusted to any required degree so as to adapt the
instrument to the measurement of more or less intense force by making
one or both of the two pieces A, B, and C, D, to which the fibres are
attached respectively capable of rotation about the line L, M, so that the
lines A, B, and C, D, can be adjusted to and fixed at such relative
angular positions as shall be found by trial to give the degree of
stability or instability required under the circumstances of the case.

page_text: When the indicator is directed by fixed magnets or otherwise, and it
is desirable to have the means of diminishing its stability, then it may
be suspended by a double bifilar suspension in the mode described
arranged in a manner which would independently of the magnet give
instability. This will diminish the too great stability which it has from
the magnet.
-
Fifth Part. In using the method of suspension described in part 4,
or any of the ordinary modes of suspension by fibres or wire, when any
one of the supporting or guiding wires or filaments in any of these
arrangements is of a conducting substance and of sufficient conductivity,
and when it is desired to make or break an electric circuit or electric
circuits by the motions of the indicator, I use that wire or filament or
one or more of those wires or filaments for bringing into circuit a piece
or pieces of platinum or other metal attached to the indicator touching
a metal stop or detached from the same according as the indicator is on
one side or the other of its mean position or any other suitable arrange-
ment for making and breaking circuit. When none of the suspending
or directing filaments are of conducting material, and when it is desired
to have a circuit or circuits made or broken by the motion of the indicator,
I use a vessel containing a conducting liquid and a conductor connected
with the indicator dipping into the conducting liquid to maintain the
electric communication between the indicator and the fixed parts of
the circuit or circuits

page_text: be due north of the primary indicator and without stops, one half of the
rest of the secondary indicators are placed at successive distances to thic
east, each with a stop which prevents its north end from moving to the
east, and the other half at like successive distances to the west, and cach
with a stop which prevents its north end from moving to the west. When
the primary indicator is in its undisturbed position, all the secondary indi-
cators are held against the stops except the first or central one which is
then also pointing north. When a positive current of the first strength
is sent through the wire, the primary indicator or one of the two primary
indicators moves through a given angle to the east or west, but say (to
fix ideas) to the east, and moves only the first of the easterly set of
the secondary indicators, the north end of such secondary indicator
moving to the west. When a positive current of the second strength
is sent through the wire the primary indicator is deflected through a
greater angle to the cast, and the second of the same set of the secondary
indicators is moved. When a positive current of the third strength is
sent through the wire the primary indicator is deflected through a still
greater angle to the east, and the third of the same set of the secondary
indicators is moved, and so on, and so vice versa as regards the west
set of secondary indicators when negative currents of the first, second,
and third strength are sent through the wire. The motions of the
secondary indicators may be observed and read off or recorded in any of
the ways now in use or in any of those described in this Specification
adapted to the purpose, or may be used to make or break contact for
local batteries, and thus be used as a relay for a transmitting or recording
instrument, or in any operations connected with the manufacture or use
of electric telegraphs for which it is suited.
Although in what precedes I have for distinctness supposed the
primary and secondary indicators in their undisturbed position to point
north and south, they may often be more conveniently directed in some
other direction by fixed magnets, or by any of the modes of suspension
described herein, in that case for north, south, east, and west in the
preceding description must be substituted corresponding directions
relative to the actual position of undisturbed equilibrium.
Eighth Part. I use either of the electrometers described in the first
part as a receiving instrument or an instrument to be used in making
comparisons of clocks, or in giving time, or for any other purpose
connected with the manufacture or use of electric telegraphs worked

page_text: otherwise than by frictional electricity. I prefer for this purpose the
electrometer first described above.
Ninth Part. I also use thermal effects produced by radiant heat
reflected from a mirror or reflecting surface of any kind attached to the
indicator of a receiving instrument for the purpose of having the indi-
cations recorded. The thermal effects which I thus use may be eitlier
first the melting of wax or of any other fusible substance forming a
layer which is moved with a steady motion across the line of motion
of the beam of radiant heat, or any chemical or other change produced
in the quality or appearance of any substance by heat, or secondly,
thermo-electric effects in local circuits excited by the radiant heat.
The last-mentioned kind of effects may be used in the construction
of a third kind of galvanometric relay in which one or two or more
thermo-electric circuit are excited according to the distance and the
direction of any excursion of the beam of reflected radiant heat, and
produce motions in moveable magnets or indicators by which the electric
currents to do the work wanted may be checked or permitted to pass as
required.
Tenth Part is disclaimed.
Eleventh part is disclaimed.
Twelfth Part. I use clectric sparks excited by a Ruhmkorff coil or
any other convenient instrument, and passing between any part of the
indicator and a sheet of matter fixed or carried along by a regular
motion near it to record by impressions, by chemical changes, or by
perforations produced by these sparks the motions of the indicator.
I also use electric currents sent through a conducting liquid covering
part of the moveable body so as to make impressions, chemical or other,
on a sheet also covered by a liquid.
the
In using electric sparks to record the indications of a moveable body
in a galvanometer or galvanometric relay employed for telegraph
purposes I employ a regular succession of sparks following one another
at very short intervals of time, each making a mark on the paper or
other sheet receiving the impression or perforation. In using this part
of my Invention I prefer to cause a strip of paper sensitive to photo-
graphic action or otherwise, to travel with a steady motion across the path
of the end of the indicator over a metal plate, above which plate the end
of a conductor projecting from or forming part of the indicator moves to
and fro in consequence of the action of the current transmitting signals.
The series of sparks excited by the Ruhmkorff coil or other instrument

page_text: takes place between the before mentioned end of a conductor and the
metal plate, and makes a series of marks on the paper cither by photo-
graphic action, or perforation, or both. The result is an undulating
curve of dots, the character and succession, of the undulations of which
give the different signals desired to be sent.
Thirteenth Part. I use an apparatus by means of which electric
signals may be read off by observing the amount, greater or less, of
motion of an indicator, and that by observing the same directly or by
observing the motion of a spot of light reflected from a mirror carried
by the indicator and thrown on a graduated screen or received by a
telescope, such greater or less amount of motion being produced by
currents of greater or less strength regulated as herein-after described.
For this purpose I prefer to attach to the indicator a very light mirror
reflecting a beam of light, which beam produces a luminous spot or line
on a graduated screen, by the motions of which spot or line the corre-
sponding motions of the indicator are made visible. It is useful to
employ a lens for concentrating and bringing to a focus the beam of
light, in which case the screen should be at or near the focus of the lens.
When I use a lens for the before mentioned purpose I prefer that it
should form part of the casing by which the indicator is protected from
currents of air. The illuminating beam of light enters the casing
through the lens, is reflected from the mirror, and leaves the casing
through the lens again. Figure 4 represents on a scale somewhat larger
than the actual scale the indicator which I prefer for a galvanometer
with one thread, wire, or fibre. A is a cylinder of brass with glass
ends. I usually make one or both ends of the form of lenses. B, a
small mirror hung by the fibre D in the interior of the cylinder; C, C,
a small steel magnet or indicator, fixed to the mirror. A small circular
plate placed behind the indicator and moved backwards and forwards by
a screw forms an adjustable stop for checking its oscillations and
limiting the range. Figure 5 represents, on a scale about one quarter of
the actual dimensions, one of the galvanometers which I use. A is the
bobbin with its coil of conducting wire fixed upon a stand which has
levelling screws. B, B, B, B, B, B, B, studs connected with the coil at
different points so as to enable the operator to send the electric current
to be measured through different lengths of coil, according to the
sensibility required in the instrument; C, central aperture in the bobbin,
into which is inserted the cylinder containing the indicator represented

page_text: for the current
in Figure 4; D, E, handles for adjusting the position of a fixed magnet
which is concealed beneath the stand of the galvanometer, and which
regulates the stability of the indicator. One of these handles turns a
tangent screw, which drives a horizontal pinion so as to turn the
magnet into any required direction, the other handle turns a vertical
pinion which works into a vertical rack so as to place the magnet at any
required depth below the bobbin. Figure 6 represents another of the
galvanometers which I use. A, bobbin with the coil, to be measured;
C, opening containing the magnet or indicator with its mirror, as
before; B, B, a pair of bobbins with the coil, through which a constant
current is transmitted. The axis of this coil is perpendicular to that of
the coil A. When no current traverses the coil A the indicator places
itself along the axis of B, B; when a current traverses the coil A the
indicator deviates through an angle depending on the strength of that
current; D, pinion; and E, clamp screw for adjusting the angular
positions of the coils B, B, and A. The adjusting coil B, B, will be
again referred to under the head of the Twentieth Part of my Invention.
Fourteenth Part. In long lines of submarine telegraph I use
apparatus by which for a single signal an electric current of a stated
strength is as rapidly instituted in a telegraph wire as possible, and
maintained as nearly as possible at the stated strength until an indication
is taken from it by any of the receiving instruments, galvanometers,
relays, or electrometers described above, or by any other which may be
convenient. The indication must be of such a kind that from it, with
due allowance for the electric condition of the wire as effected by
previous operations, it may be possible to estimate what was the strength
of current arranged for at the transmitting end. According to the
strength of current (positive or negative) thus estimated one number or
another, one letter or another, one word or another, one piece of
intelligence or another is read off, according to a pre-arranged code.
I use a Daniell's or other constant battery or any other electro-motor by
which definite and sufficiently exact measured amounts of electro-motive
force can be applied for making electric signals of this kind. I use the
following plan for making the current as rapidly as possible approach
the stated strength for any signal, and that whatsoever may have been
the strength employed in the signal immediately preceding it or in any
of the preceding signals. When the wire is unelectrified, to begin with,
then I apply first a stronger electro-motive force than that required to

page_text: maintain the current at the stated strength for a short time, and after
that I apply the electro-motive force just required to maintain a current
at the stated strength, and continue such application until the time
comes to make the next signal. I next apply for a short time an electro-
imotive force differing from the last by a greater amount than that by
which the electro-motive force corresponding to the new signal differs
from it, after which the electro-motive force simply required to maintain
the stated strength corresponding to the new signal is applied and held
on until it is time to commence a third signal, and so on.
I also in some cases use the following plan:-I apply constant battery
power during a certain measured interval of time, then another battery
power during another equal interval of time, and so on; these degrees of
power equal or unequal, as the case may be, being each determined by
calculation or otherwise so as to compensate so far as is required the
residual effects of preceding operations, and at the same time to produce
a new effect constituting or contributing towards a new signal.
The method of performing this and similar operations will be best
understood by an example, such as the following:-To get a letter every
three seconds I apply by means of a pendulum and clockwork apparatus
during one second a certain strength, say, forty-eight of positive electro-
motive force, during the next second fifty of negative electro-motive
force, during the third second twelve of positive electro-motive force.
The effect at the receiving end of a certain length of line is to make the
indicator move to a positive maximum of deflection corresponding to
the letter required, and fall back to zero, or nearly to zero, before it
commences to indicate the effect of a similar succession of operations
made for another letter during the next three seconds. The proportionate
strengths for different simple signals are the same for the same line of
telegraph and speed of working, the absolute strengths alone being
different. For different lines of telegraph and different speeds of working
the proper proportions of the electro-motive forces in each case can best
be found by experiment on the line itself.
In order to illustrate this part of my Invention, Figure 9 represents
apparatus which I use in carrying it into effect on a scale of about one
half of the actual dimensions. In order to render that Figure as easily
intelligible as possible I have simplified it in cases in which several parts
or sets of parts of the apparatus are exactly similar to each other in
construction and use, by shewing only one such part or sets of parts. I

page_text: have also omitted such ordinary and well known details of mechanism
and framework, as any instrument maker can easily supply and can vary
at his discretion, because such details would complicate the Drawing and
conceal the essential features of the Invention which it illustrates. I
wish it also to be understood that every conductor represented in the
Drawing is insulated by the ordinary means of insulation from all
clectrical communication with other bodies, except such communications
as are specially mentioned in the description.
A1 and A4, A2 and A 5, Á 3 and A6, are three pairs of wires
connected with a galvanic battery (not shewn) at such three pairs of
points as are suitable for producing the three successive currents
required for making a certain given signal, A3, A2, A1, being the
three conductors which in order to produce that signal are successively
to be connected with the line wire, and A 6, A5, A 4, those which are
successively to be connected with the carth; these six wires are re-
spectively connected with six studs B1, B2, B3, B4, B5, B6, fixed on
a board underneath a key D; C1, C2, C3, C4, C5, C6, are six springs
which are brought into contact with the respective studs when the key
is depressed, and which rise and break contact when the key is not held
down; the key turns on a rod at E; there are as many keys, each with
its six wires, six studs, and six springs, as there are distinct simple
signals in the code of signals, but according to the principle already
stated only one key with its adjuncts is shewn. F is an arbor made to
rotate by clockwork, the motion of the clockwork is regulated by a
pendulum and a dead beat escapement. I have hitherto used a pen-
dulum beating seconds; the arbor F makes one revolution consisting of
twenty-four beats or jumps for each twenty-four swings of the pendulum.
G is a circular cam having four equidistant teeth; H is a lever which is
lifted and dropped once in every six beats by the teeth of the cam J, a
fixed stud, to which is attached a spring for holding H down when not
lifted by a tooth; for this spring a weight might be substituted. I, an
arbor carrying the lever H and also another lever K, which passes at L
through an opening or slot in the key D, in that slot is seen a cross bar
fixed to the key, and under the cross bar is a pin projecting from the
lever K, and each key in the row of keys is provided with a similar lever
pin and cross bar; when the lever H is not lifted the pins projecting
from the lever K being below the cross bars of the keys lock the keys
and prevent their being depressed; when the lever H is lifted the pins

page_text: are all drawn back and all the keys of the row are unlocked at once
for an instant and then locked again. Should the clerk using the
instrument press upon any key it descends at the instant of unlocking,
and when the keys are again locked the pin is above instead of below
the cross bar of the depressed key, so that that key is held down and
the contact of its springs and studs maintained until the next unlocking,
that is, for six beats of the clockwork; M1, M2, M3, M4, M5, M6, arc six
wires respectively connecting the six key springs C1, C2, C3, C4, C5, C6,
with six springs N1, N2, N3, N4, N5, N6, which I call first cam springs.
There is only one set of six first cam springs for the whole of the keys
in a row, all the key springs corresponding to the springs C1 for the
several keys being connected with the single cam spring N1 all the key
springs corresponding to C2 with the single cam spring N 2, and so on.
The three cam springs N3, N 2, N1, are made to communicate succes-
sively with the line wire at the same instants that the other three cam
springs N 6, N 5, N4, are made to communicate successively with the
earth by means presently to be described; P1, P2, P3, P4, are four cams
carried by the arbor F, which I call respectively P1, P3, the line cams,
and P 2, P 4, the earth cams. Each of those cams is insulated from the
arbor and cach consists of two discs of different diameters. The smaller
discs are circular and are always in contact respectively with the
springs Q1, Q2, Q3, Q4, which I call the second cam springs. Each of
the larger discs has four similar equidistant projections, whose outer
surfaces are portions of one cylinder, and each of those projections
occupies a little less than one-twelfth part of the circumference of
the disc. The positions of the cams on the arbor and those of the
ends of the six first cam springs are so adjusted that when the arbor
rotates the projections of the two pairs of cams come into contact
successively with the ends of the three pairs of first cam springs in the
following order, that is to say, immediately on the unlocking of the
keys, the pair of first cam springs N 3, N 6, are brought into commu-
nication with the cams P1, P2, and through them with the pair of second
cam springs Q1, Q2, next the pair of first cam springs N 2, N 5, are
brought into communication with the pair of cams P3, P4, and through
them with the pair of second cam springs Q3, Q4, and lastly the pair of
first cam springs N1, N 4, are brought into communication with the pair
of cams P1, P2, and through them with the pair of second cam springs
Q1, Q2, and so on in rotation. The second cam springs Q1, Q2, Q3, Q4,
communicate respectively by wires R1, R2, R3, R 4, with two pairs of

page_text: studs S1, S2, S3, S4; U is part of the rod of the pendulum which regu-
lates the motion of the clockwork; T1, T2, are a pair of flat springs, which
I call the pendulum springs, insulated from each other and fixed across the
pendulum rod by which they are carried; T1 communicates through an
extensible conductor V with the line wire, and T 2 communicates through
an extensible conductor V2 with the earth. When the pendulum is to
the right of the vertical position the springs T1, T2, are in contact with
the studs S 1, S2; when the pendulum is to the left of the vertical position
the springs T1, T2, are in contact with the studs S3, S4, when the pen-
dulum is in the act of passing the vertical the springs T1, T2, are not in
contact with any of those studs. The effect of this is, that during the
second half of each swing of the pendulum towards the right and during
the first half of each swing towards the left, the line cam P¹ communicates
through Q1, R1, S1, T1, and V1 with the line wire, and the earth
cam P2 communicates through Q2, R2, S 2, T2, and V 2, with the
earth, and that during the second half of cach swing towards the left,
and the first half of each swing towards the right, the line cam P3
communicates through Q3, R 3, S3, T1, and V1, with the line wire,
and the earth cam P 4 communicates through Q4, R4, S4, T2, and V 2,
with the earth..
The combined effect of the whole apparatus is this-When the clerk
presses on a given key the locking and unlocking apparatus allows the
key to descend at a certain instant, and holds it down for six beats of
the clockwork, in the course of which time the six key springs and their
studs maintain two portions of each of the three circuits required for the.
three currents proper to produce the signal wanted. By the action of
the three pairs of first cam springs and of the two lime cans and two
earth cams, two other portions of each of those three circuits are
maintained for the three circuits successively. By the action of the
pendulum and its springs each circuit is completed in succession, and
maintained complete during a definite interval of time, being that of
two half swings of the pendulum, that is to say, one second. I prefer to
have a second row of keys on the same instrument; in that case, either
by suitably placing the locking and unlocking lever of the second row
corresponding to H, or by having a second cam corresponding to G,
I cause the second row of keys to be unlocked at the instants exactly
midway between the instants at which the first row of keys is unlocked.
I have also a second set of first cam springs corresponding to those

page_text: marked N 1, &c. for the second row of keys, which springs in the Figure
are marked N, and numbered from 7 to 12, and the wires which connect
them with the key springs of the second row are marked M, and
numbered from 7 to 12 also, but the second row of keys is not shewn.
The contacts for making the circuits through the pairs of springs
numbered 9 and 12, 8 and 11, 7 and 10, take place in succession during
the interval following that which is occupied by the contacts for making
the circuits belonging to the first row of keys. The two rows of keys
may be used either to give a more rapid succession and a greater variety
of signals than one row can conveniently produce, or to enable two
clerks to work at the same time, according to the method already
described under the head of the eleventh part of my Invention.
Although I have now described an instrument regulated by clockwork
for carrying into effect the fourteenth part of my Invention, I wish it.to
be understood that that part of my Invention is also capable of being
carried into effect, and that I sometimes do carry it into effect by instru-
ments in which the duration of each current is regulated by hand, the
clerk or operator having a metronome, a clock beating rapidly, or other
suitable instrument near him to regulate his estimation of time, and for
that purpose I have a set of keys, cach of which while depressed causes
a certain fixed amount of electro-motive force to be applied to the
telegraph wire, and to make a given signal, a certain specified pair or
set of keys are depressed in a specified order during specified intervals of
time, determined by experiment and calculation, as herein-before stated.
One convenient arrangement is as follows:-There are two rows of keys,
an upper and a lower, each containing the same number of keys, each
key of the upper row being depressed maintains a certain amount of
electro-motive power force in the telegraph wire, and the key imme-
diately below in the lower row remains the same force in the opposite
direction. When none of the keys are depressed the telegraph wire is
connected with the earth to make a current in a given direction at the
remote end of a long line of telegraph wire, which shall rise rapidly to a
stated strength, and then fall rapidly to zero, or nearly so; an electro-
motive force of a given amount is to be applied at the near end, first in
the direction of the desired current for a certain time, and then an equal
electro-motive force is to be applied in the opposite direction for a certain
time of less duration than the first, the proper intervals of time being
sensibly the same for all required strengths of current to be produced at
maintains

page_text: the remote end are found once for all by experiment a more accurate
mode of securing that the different electro-motive forces are applied for
the proper intervals of time, which I also use is to make and break the
contacts by means of a pendulum so constructed as to swing on one side
of its point of rest in a different time from that in which it swings on the
other side, these two times being arranged so as to be the times for
applying the two different forces. I also attain the same object by
using a wheel moved by clockwork or other motive power giving a
regulated motion, by hand, and regulated by a fly wheel or governor,
and having cams adjusted so as to make and break contact at the
proper intervals.
or moved
^
Fifteenth Part. When it is desired to work through a submarine line
or through a very long air line in both directions at once, then in order
to avoid the comparatively violent action which is caused in the receiving
instrument at the transmitting end by transmitting signals from that
end through it, I throw the receiving instrument at the transmitting
cnd out of circuit during certain parts of the time during which a
signal is being transmitted from that end. I regulate the time during
which the signal is transmitted by such arrangements of wheels and
cams as before described, and by a separate wheel on the same arbor
with proper cams I regulate the times during which the receiving
instrument is thrown out of circuit.
Sixteenth Part.-I compensate the effects produced by currents.
transmitted from one end on the indicator of the receiving instrument
at that end, so that the indications of that instrument are either not
sensibly affected by them or that the indications it would have given
had it not been effected by them may be estimated. I produce that
compensation by sending while the receiving instrument at the
transmitting end is in circuit a current through a compensating coil
near it, that compensating current acting upon the indicator of the
receiving instrument at the transmitting end at the same time that it
is acted upon by the principal current of transmission but in an opposite
direction. The compensating current is not necessarily of the same
strength with the current of transmission, but may be stronger or
weaker in any proportion according to the length, form, and position of
the compensating coil, its strength being regulated so as to compensate
the effect of the current of transmission. Thus I dispense with the

page_text: "
In my Provisional Specification the nature of the twenty-first part of
my Invention is stated as follows:-"In the use of galvanometers or
"galvanometric relays, or of any other kind of relay or receiving instru-
ment, I propose, in order to compensate the effect of electrification of
"the telegraphic wire remaining over from previous signals, to use in
"the neighbourhood of the moveable indicating body an electro-magnet
or coil of wire
conveying a current instituted and regulated
"to produce the desired effect, or a steel or other magnet moved so as
"to produce the desired effect. When it is not convenient to make
"allowance for such residual effects from previous signals by calculation
or otherwise, and when they are of such an amount as to exercise a
"sensible disturbance if not compensated, I propose to use similar appa-
ratus under similar conditions in sending messages through either a
"land or a submarine line in both directions at once, for the purpose of
compensating the effect on any receiving instrument due to signals
"transmitted in the direction contrary to that from which the signals
"to receive which it is employed are coming;" but so far as I use and
intend to proceed with that part of my Invention it is comprehended
under the sixteenth part of my Invention, and the manner in which it
is to be performed is herein-before described.
66
"
separato
^
Twenty-second Part.-I use two mirrors attached to the indicators of
two galvanometers at the receiving end of and receiving currents from
one transmitting station by two telegraph lines, and I cause a ray.
of light to be reflected from these two mirrors in succession, and to
be thrown on a screen so as to give a visible effect, or by photographic
or thermal influence a recorded effect, by which any lines, figures, letters,
or symbols drawn or written at the transmitting station upon an instru-
ment adapted to give different degrees of electro-motive force to the two
lines according to the two independent variables thus dealt with may
be written, drawn, or made visible at the receiving station. For trans-
mitting a line, drawing, or writing of any kind by telegraph I add a
third telegraph wire, which is so connected and arranged that when the
tracing point at the transmitting station is lifted from the surface on
which the curve is drawn the indicating or marking beam of light is cut
off at the receiving station. The manner of performing this part of my
Invention may be varied in its details, but one method is as follows:-.
I prefer that the tracing point at the transmitting station should move
on a horizontal plane. To fix the ideas I distinguish the two components

page_text: of the motion of the tracing point as the north and south component
and the east and west component. A row of studs running north and
south are connected with different points in a battery so as to give a
series of electro-motive forces of graduated strengths. A conductor by
means of a parallel motion accompanies the tracing point in its north
and south motion, and by touching one or other of the row of studs
establishes a current in one of the line wires of a strength suitable to
cause one of the mirrors at the receiving station to take an angular
position corresponding to the deviation of the tracing point to the north
or south of its middle position. Another row of studs running east and
west is connected with different points in another battery so as to give
a series of currents of graduated strengths. A conductor by means of a
parallel motion accompanies the tracing point in its east and west
motion, and by touching one or other of the second row of studs
establishes a current in the second line wire of a strength suitable to
cause the second mirror at the receiving station to take an angular
position corresponding to the deviation of the tracing point to the east
or west of its middle position. A ray reflected successively from the
two mirrors performs motions sensibly similar to those of the tracing
point. There is a screen which intercepts the beam unless drawn, back
by an electro-magnet; that magnet is made to act by a current tra-
versing the third line wire, and part of the circuit conveying that current
is formed by the tracing point and by a metal plate on which it is moved,
so that by lifting the tracing point the beam is intercepted.
In using every part of my Invention the details may be varied without
departing from the principle of the Invention.
I do not claim the mechanical movements and other elementary
parts of the apparatus herein-before described otherwise than as hercin-
after mentioned; but what I do claim is, that which is stated or
referred to in the following statement, that is to say:-In connection
with the first part of my Invention I claim the method of testing a
the above-described
Λ
telegraphic conductor by the aid of electrostatic instruments in the
manner herein-before described. I also claim the electrometer first
herein-before described so far as regards the use of a testing conductor,
consisting of two or more parts so formed and arranged that when all
are electrified to the same potential they shall have no directive effect
on the indicator, and so far as regards the usc in combination with such
a testing conductor, of an indicator independently charged to and main-

page_text: tained at a high potential, and I claim such instrument for all purposes
connected with the testing either in the course of manufacture or after-
wards, or in the working of electric telegraphs, in which term I include
all telegraphs worked by electricity in whatever way such electricity
is excited, and also so far as any of the other arrangements of the
first-mentioned electrometer are comprised in any other part of my
claim.
⚫ secondly
and also so far as regards the connecting the indicator
I also claim the electrometer, herein-before described so far as regards
the use of the drum herein-before described enclosing the indicator, with
the earth, and insulating the drum and connecting it with the conductor
to be tested.
In connection with the second part of my Invention I claim the
method of testing the insulation of a telegraph wire therein described.
In connection with the third part of my Invention I claim the marine
galvanometers herein-before described so far as regards the suspension
of the indicator by a stretched fibre passing through its centre of
gravity, and so far as any other parts of the arrangement are comprised
in any other part of my claim.
In connection with the fourth part of my Invention I claim the double
bifilar suspension for indicators herein-before described.
In connection with the fourth and fifth parts of my Invention I claim
the use of a suspending or supporting filament or filaments of the
indicator of any of the instruments herein-before mentioned as part of
a conducting circuit connecting the indicator with another conductor.
I also claim the use for the same purpose of a conductor dipping into
a conducting liquid in connection with the first and fifth parts of my
Invention, and as described in the part of this Specification wherein
those parts of my Invention are described. I do not claim the usc
of conducting filaments or of conducting liquids except in telegraphic
apparatus.
In connection with the seventh part of my Invention I claim, the
use of secondary indicators to indicate, receive, record, or transmit
signals depending on the motions of primary magnets or indicators in
the manner herein-before described..
In connection with the eighth. part of my Invention I claim the use

page_text: of the above-described electrometers as receiving instruments for
telegraphic signals made by electricity other than frictional.
In connection with the ninth part. of my Invention I claim, the use
of the thermal effects of rays reflected from the indicator in manner
herein-before described for the purpose of receiving, recording, or
transmitting telegraphic signals.
In connection with the twelfth part of my Invention I claim, the use
of electric sparks in manner herein-before described for receiving or
recording the telegraphic signals herein described by means of marks,
impressions, chemical changes, or perforations, produced by these
sparks.
In connection with the thirteenth part of my Invention I claim, the
use of a transmitting instrument adapted to send currents of various
measured strengths combined with the receiving instrument constructed
as herein described and adapted for receiving and recording the de-
flections of the indicator caused by the different strengths of current
and for giving a variety of signals thereby.
In connection with the fourteenth part of my Invention I claim the
methods and apparatus herein-before described for rapidly producing,
and for maintaining electric currents of stated strengths in telegraphic
wires and for discharging currents from such wires.
In connection with the fifteenth part of my Invention I claim, the
arrangements for throwing the receiving instrument at the transmitting
end out of circuit during part of the time during which a signal is being
transmitted from that end, in the manner and for the purposes herein-
before described.
In connection with the sixteenth part of my Invention I claim, the
compensating the effects produced on the receiving instrument at the
transmitting end by operations performed at that station by means of
such a compensating current or moveable magnet as herein-before
described.
In connection with the so-called nineteenth part of my Invention I
claim nothing.
In connection with the twentieth part of my Invention I claim, the
method and apparatus herein-before described for increasing, diminishing,
or regulating the stability of a moveable magnet.

page_text: In connection with the twenty-first part of my Invention I claim
othing beyond what has already been claimed in connection with the
xteenth part of my Invention.
In connection with the twenty-second part of my Invention I claim
he method and apparatus herein-before described for producing at a
eceiving station lines, figures, letters, or symbols of given shapes.
In witness whereof, I, the said William Thomson, have hereunto
set my hand and seal, this Nineteenth day of August, in the year
of our Lord One thousand eight hundred and fifty-eight.
I hereby grant my fiat giving leave to the above-named William
Thomson to file in the Great Seal Patent Office, with the Specification to
which the same relates, the above written Disclaimer and Memorandum
of Alteration, dated this Eighteenth day of May. One thousand eight
hundred and seventy-one.
Temple.
R. P. COLLIER,
Attorney-General.