IMPROVEMENTS IN ELECTRIC TELEGRAPHS
Year: 1872

page_text: Sealed the 14th February 1873, and dated the 11th November 1872.
COMPLETE SPECIFICATION filed by the said Joseph Barker Stearns
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 11th November 1872, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
BARKER STEARNS, of Boston, in the County of Suffolk, and State of
Massachusetts, and United States of America, Electrician, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
ELECTRIC TELEGRAPHS," and have petitioned Her Majesty to grant unto
me, my executors, administrators, and assigns, Her Royal Letters
Patent for the same, and have made solemn Declaration that I am the
true and first Inventor thereof.

page_text: NOW KNOW YE, that I, the said Joseph Barker Stearns, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed, in and by the following
statement:-
This Invention relates to certain improvements in the apparatus
employed for transmitting telegraphic communications simultaneously
in opposite directions over the same conductor.
These improvements consist,-
5
First. In certain improved modes of constructing the electro-magnets 1
for receiving instruments, by means of which the effect of the out-
going electric currents upon the armature of the said electro-magnet or
magnets are more perfectly neutralized.
Second. In an improved arrangement of the rhcostats or artificial
resistances in combination with the circuit breaker, by means of which 1
the resistance opposed to the battery at each station is always practically
the same, whatever may be position of the apparatus at the opposite
station.
Third. In an improved mode of constructing and operating the circuit
breaker or key, which transmits the electric currents upon the main
line.
fr
Fourth. In the application of a condenser," or other equivalent
device to the apparatus, by means of which the effect of static induction
in operating either land lines or submarine cables is neutralized or com-
pensated for.
65
Fifth. In the manner of placing a relay or other receiving instrument,
in the circuit of a bridge wire," so that said relay, or other receiving
instrument will be operated by received currents, and not by transmitted
currents.
Sixth. In a repeater or translator for use in telegraphic apparatus for
double transmission.
Seventh. In an arrangement of circuits, whereby one or more branch
offices are enabled to operate the transmitting key or circuit breaker at
the main office, and also whereby the receiving relay at the main office
is caused to operate a receiving instrument at said branch office or

page_text: offices for the purpose of establishing direct communication between the
branch office in one place and the main office or branch offices in one
or more places, or vice versa.
Eighth. In an arrangement of telegraphic apparatus, whereby way
5 stations are enabled to communicate with either or both terminal stations,
employing duplex instruments or double transmitters.
In the accompanying Drawings, which illustrate this Invention,
Figure 1 is a theoretical Diagram representing two telegraphic stations
connected by a line, and arranged upon this improved plan.
0 Figure 2 is a modification of the said arrangement, in which a
receiving magnet of ordinary construction is employed.
Figure 3 is a Diagram, showing the arrangement of a translating or
repeating station.
Figure 4 is a Diagram, showing the arrangement of a terminal station
5 in conjunction with two auxiliary or branch stations.
Figures 5, 6, 7, 8, 15, and 16 are modifications in the manner of con-
structing the receiving magnets or relays.
Figures 9, 10, and 11 are modifications in the manner of constructing
the circuit breakers and transmitting keys.
Figure 12 is a modification of my Invention, more particularly relating
to the manner of arranging and connecting together the different portions
of the apparatus.
Figure 13 shows a method of arranging my Invention, so as to enable
an intermediate station to communicate with either or both terminal
5 stations, or in cither or both directions.
Figure 14 is a modification of the plan of arrangement shown in
Figure 2; and,
Figure 17 illustrates three modes of applying induction coils in place of
condensers.
The principle of operation in this apparatus is founded on the estab
lished law that an electric current will divide itself between any two
conductors open to it in inverse proportion to their respective resist-
If the two resistances be equal to each other the strength of the
respective divisions of the current will likewise be equal. Also, if two
ances.

page_text: equal currents be transmitted in opposite directions through two parallel
wires, each having an equal number of convolutions around an electro-
magnet they will neutralize each other, and their effect upon the magnet
will be null.
-
A and B (Figure 1) represent the two terminal stations of a line.
The main battery E at station A is placed with its positive or + pole to
the line, while the battery E' at station B has its negative or
pole to
the line. M and M³ are the receiving magnets or relays, the helices of
which are wound with two parallel wires of equal length and resistance,
and having an equal number of convolutions. The rheostat or resist-
ance X is capable of adjustment, and is so regulated as to be always
equal to that of the line A, B, added to the battery E¹, and one wire of
the relay M¹ at B. And the rheostat or resistance X' must be made
equal to the line added to the resistance of E, and one wire of M. The
positive pole of the battery E at station A is connected to the lever K,
the latter forming a portion of the main circuit. The lever K is pro-
vided with an armature 8, so arranged as to be capable of being attracted
by the electro-magnet S, which is actuated by a local battery L when-
ever the key F is depressed, the arrangement of the circuit being shown
by the dotted line in the Drawing.
In practice it is preferable to construct the electro-magnet S and
lever K in the form of an ordinary "sounder," the lever K acting as a
transmitting key or circuit breaker for the main line. The advantage of
this arrangement is that the transmitting operator can hear his own
manipulation repeated upon the sounder, and is enabled to better guard
against errors. Another incidental advantage is that the transmission is
effected with more firmness and regularity than when a finger key is
employed.
A supplementary lever is pivoted at o, and provided with adjustable
screws m, n, for making electrical contacts as herein-after explained.
R is the register or sounder for receiving communications, which is
operated by a local battery i connected with the receiving magnet M

page_text: The manner in which the apparatus is made to operate is as follows:-
If the transmitting key F at station A, for example, be depressed the
local circuit through the magnet S will be closed, and the armature s
attracted thereby moving the opposite extremity of the lever K, so as to
bring it into contact with the screw m, while the same movement will
release the screw n from its previous contact with the anvil p. The
current of the main battery E will now flow through the levers K and k
to the point 1, where it will divide into two equal portions, one half of
it going through one wire of M to 3, thence over the line to and
through the relay M³ to 5, and thence through k' and p¹ to the earth,
and the other half will pass from the point 1 in an opposite direction
through the relay M to the point 4, and thence through rheostat X
to the earth.. The "home" relay M being thus acted upon simul
taneously by equal and opposing currents will remain entirely unaffected.
The relay M¹ however will be affected by the current passing through the
wire 7, 5, and will give signals corresponding to the movements of the
key F and levers K, k.
If now the key F¹ at the station B be depressed the same action takes
place; one half the current passes through one wire of the relay M
and over the line combining with the current from station A, and
the other half returns to the earth through the other wire of the
relay.
The relay wires 1, 3, and 7, 5, are now traversed by a double current
E E¹
equal to +
2
2
'
but the wires 2, 4, and 6, 8, are traversed only by the
E
current of a single battery, having at station A the force of 1, and
E¹
2'
2
at station B the force of The latter currents being in an opposite
direction to the former the relays at both stations are affected by the
E E' E
difference in the forces of these currents; the relay M by +
2
E
E¹
2
and the relay M' by (+2) - Thus cach relay responds only to
the action of the distant battery, and not to that of the battery at its
own station.
When the current from the distant station, for example from B,
arrives at the point 1 two different routes are open to it; one by the
wire 2, 4, and rheostat X to the earth, and the other to the lever k, and

page_text: thence to the earth, either through n and p or through m, K, and E,
according to the position of the circuit breaker K, k. But in accord-
ance with the law hercin-before referred to the resistance by the
first-mentioned route being very great in proportion to that of the
other, but a very small portion of the current will take that route, and
its influence upon the relay M will not be appreciable.
It is obviously a matter of great importance that the resistance
presented by the apparatus at one station to the current from the
opposite or remote station should always be perfectly uniform irre-
spective of the position of the circuit breaker. To effect this it is
necessary that the resistance between the lever k and the earth by the
way of n and p should be exactly equal to that by the way of m, K, and
E. A small resistance », which is made equal to the internal resistance
of the battery E, is therefore interposed between the anvil p and the
carth.
It will be evident that at each vibration of the circuit breaker the
lever will be momentarily in electrical connection both with K and p,
during which time the battery E will be "short circuited." In order to
prevent the too rapid consumption of battery power from this cause a
sufficient resistance x may be inserted into the battery circuit if
desired. When this is done the resistance of the rheostat must be
made equal to the combined resistance of the rheostat x and the
battery E.
In working through submarine cables or land lines, especially when
they are of considerable length, the return charge arising from static
induction, after the circuit is broken, has heretofore been found to inter-
fere with the operation of the instruments. Where this is found to be
the case a condenser C, consisting of alternate sheets of metallic foil and
paper or other insulating substance, is employed. The first, third, fifth,
etc., metallic sheets are connected together, and to the wire between the
rheostat X and the relay M, as shown in Figure 1; while the second,
fourth, sixth, etc., sheets are connected with each other, and with the
earth. If the static capacity of the condenser is adjusted to equal that
of the line it is found to entirely compensate for and remove the effects
of inductive action. Whatever static charge may be induced upon the
linc A, B, the equal current in the wire 4 will induce a corresponding
charge in the condenser C, and both will be thrown through the separate

page_text: wires of the relay M in opposite directions at the same instant, and
their effect will consequently be climinated.
Instead of a condenser an electro-static or induction coil may be
employed if found preferable in practice, say in the manner shown in
Figure 17.
It is proper to remark that many modifications may be made in the
construction of the relay M, any of which may be substituted for the
one herein-before described, if circumstances require, without affecting
the principle of the Invention. Thus two distinct electro-magnets may
be so placed as to produce equal and opposite effects upon the same
armature, as in Figure 5.
An important advantage is gained by the use of this modification,
which consists in the facility with which it may be adjusted to suit the
varying condition of the line.
In the method herein-before described the adjustment of the forces
acting upon the armature of the relay depends almost entirely upon the
proper regulation of the resistance of the rheostat, which in practise is
found to be somewhat troublesome. With the double relay the exact
adjustment of the rheostat X is of little moment, as by the employment of
well-known mechanism the relative distance of the opposing magnet of
the relay from the armature may be varied, and a greater degree of
attraction in one magnet be counteracted by a lesser degree in the other
merely by bringing the latter proportionately nearer to the armature.
Another modification consists in passing the current through one helix
of the magnet in one direction, and through the other in the opposite
direction, as in Figure 6. Or two distinct helices may be placed upon
each leg of the magnet, and connected as shown in Figure 7.
For greater convenience in adjustment it is sometimes preferable to
employ the arrangement shown in Figure 8, in which the main electro-
magnet is wound with two opposing or neutralizing wires, each having
an equal number of convolutions, while a movable adjusting magnet is
placed so as to act in an opposite direction upon the same armature, and
the latter together with one of the wires of the main magnet placctl in
the rheostat circuit. The rheostat X in this modification is made con-
stant, and greater than the resistance of the line, and the compensation
is effected by moving the adjusting magnet by a slow motion screw, or

page_text: other suitable mechanism, into greater or less proximity to the armaturo
of the main magnet.
Figure 3 shows the manner of coupling two sets of apparatus together
at an intermediate station for the purpose of translating or repeating
from one circuit to another. The only modification consists in con-
ducting the local circuit from each relay to the magnet S or S¹ of the
circuit breaker on the opposite side. The receiving instruments are not
shown in this Figure, as they do not in this instance form a necessary
part of the apparatus. Finger knobs are placed upon the circuit
breaking levers K, K', so that they may be used as transmitting keys if
necessary.
Figure 4 shows the manner of arranging the connections, so that
auxiliary stations may be worked on the same line. Two stations arc
shown in the Drawing provided with keys F2 and F3, transmitting
sounders S2 and S3, and receiving instruments R2 and R³. The local
circuits from the principal office are extended, so as to include in one
circuit the three keys F, F2, and F³, and the transmitting sounders S, S²,
and S³, while a separate circuit includes the three receiving instru-
ments R, R, and R³.
,
Figure 2 shows a modification of the apparatus involving the principle
of the Wheatstone bridge, and which admits of the employment of a
common relay magnet. The outgoing current is divided at W, one half
going through the resistance coil Y and over the line, and the other half
going through the resistance coil Y¹ (which in this instance is equal to
Y), and thence through the rheostat X to the earth. The rheostat X, as
in the arrangement first described, is made as nearly as possible equal to
the resistance of the line added to that of the apparatus at the distant
station. The relay M, of ordinary construction, is placed in the circuit
of a bridge wire between the points 9 and 10. When the resistance
between W and 9 is in the same proportion to that of the line and
distant station as that between W and 10 is to the rheostat X, no
current whatever from E will pass through the wire 9, 10, and relay M,
but a current coming over the line from the distant station will divide at
9, one portion going through Y to W, and thence to the earth through
the transmitting apparatus, and the other portion going through M to
the point 10, and thence through Y¹ to W, where it joins the original
current, except a small portion, which is diverted from 10 through the
rheostat X, and thence to the carth. In practise it is found that about
half of the arriving current is diverted through the relay M.

page_text: It is not essential in all cases that Y and Y' should be equal to each
other, for by varying them in relation to each other the proportion of
the current arriving from the remote station, which passes throngh the
receiving magnet M, may also be varied.
A convenient mode of adjustment in this arrangement consists in a
movable arm W, by which a series of equal resistances Z may be divided
unequally between the two branches of the circuit, thus compensating
for any variation between the resistance of the line and that of the
rheostat X.
An important advantage of the arrangement shown in Figure 2 is
that when it is properly adjusted no portion whatever of the outgoing
current passes through the receiving instrument, thus rendering it
especially well adapted to the use of polarized magnets or electro-
chemical recording apparatus, which may be used either with or without
the relay shown in Figure 2.
If preferred the arrangement shown in Figure 2 of operating the
circuit breaker K, k, by means of an electro-magnet S and local battery L
in conjunction with a key F may be dispensed with, and the circuit
breaker attached directly to the key without the intervention of a
magnet, as shown in Figure 9. When this is done a relay Q (Figure 2)
may be inserted in the rheostat circuit, and provided with a local
circuit and sounder Q₁ for the convenience of the transmitting
operator, which will enable him to hear his own writing upon the
line.
Figure 10 shows another modification of the circuit breaker, in which
the key F is provided with two projections f₁f¹, insulated from cach
other, and to which the two poles of the main battery E are attached.
When the key F is depressed the projection ƒ makes contact with the
arm of the lever k, and at the same time moves it so as to break the
earth contact at n, while at the same instant the battery E is inserted
between and t. The resistance is made equal to the combined
resistance of the rheostat x and the main battery E, so that the resistance
presented to the line is always constant.
Figure 11 shows still another modification, in which separate bat-
teries E and E* are used for the main and for the compensating or
rhcostat circuit, and the key so arranged as to close and break both
circuits simultaneously.

page_text: When the double relay is employed a smaller battery and magnet
of less resistance may be used in the rheostat circuit if found preferable.
Any of the herein-before described forms of relay may be combined
with the modifications of the transmitting apparatus last described.
Figure 12 shows another modification, in which M is the receiving
relay wound with two equal and opposing wires, but which may be
replaced by either of the other forms of relay hercin-before described.
Q is the sending relay, which responds only to signals going out from
the station. The key K may be operated directly by hand or through
the medium of an electro-magnet and local battery.
-
When the key K is depressed the current going out from the polc
of the battery E divides at 12, one half going over the line to the opposite
station, and returning through the carth, and one wire of the relay M to
the point 13, and thence back to the battery. The other half of the
current goes through the rheostat X and the other wire of the receiving
relay M, thence through the sending relay Q, and back to the battery.
These two currents neutralize each other's effect upon the relay M, but
the relay is affected every time the key K is depressed. As the
apparatus in other respects resembles those heretofore described further
particulars are unnecessary.
The inter-
When the
Figure 13 shows a method of working with an intermediate station.
The connections and arrangement at the terminal station are the same as
shown and described in Figure 1, except that it is necessary in this case
to make use of the form of relay shown in Figure 5, and also of an
additional key K³ placed in the circuit of the main line.
mediate station is provided with a key K³ and a relay M.
operator at the intermediate station wishes to communicate he interrupts
the circuit by opening his key. The operators at the terminal station
then close their respective keys, throwing a constant current on the line.
The intermediate operator can then exchange communications or signals
with either of the terminal stations, the key K² being employed by them
for this purpose.
Figure 14 is a modification of the bridge method, shown in Figure 2,
in which two batteries are employed, and the transmitting apparatus
being the same as that heretofore described in connection with Figure 11

page_text: Figure 15 shows a modification of the relay, in which the helices are
composed of two or more distinct concentric shells (two only being
shown in said Figure) one over the other. In this form neutralization
of the cores is effected by passing the current through the wire of one
shell in one direction, and through the wire of the other shell in the
contrary direction.
I will here remark that in practise it is difficult to so proportion the
thickness of the two shells or two sets of wires that upon breaking and
closing the circuit passing through them a complete neutralization of
the magnetism due to the direct current, and also that due to induction,
is obtained. This result however is accomplished by connecting the
outer shell on one leg of the relay magnet with the inner shell on the
other leg of such magnet, and vice versa. Now it will be observed that
when the helices are composed of two sections, as shown in Figure 7,
said sections are cross connected in like manner, i.c., the back section
upon one leg of the magnet is connected with the front section on the
other leg, and vice versa, as is shown in said Figure 7.
Figure 16 shows a modification of the relay, in which the neutral-
ization is cffected by passing one part of the outgoing current through
the coils in the ordinary manner, and the other part of the current
through a coil surrounding the armature of said magnet.
It is obvious that if a current is passed through the relay in a direction
to produce north polarity in one end of the armature, say the end marked
N, P, and at the same time a current is passed through the coil sur-
rounding the said armature in a direction to produce an equal degree of
south polarity in the same end of the armature, complete neutralization
takes place, and the armature remains unaffected.
The incoming
current, passing through the coils of the relay, only will act upon it as
upon an ordinary relay.

page_text: Twelfth. A repeating apparatus constructed, and having a mode of
operation substantially as hercin described and shown in Figure 3 of the
Drawings.
Thirteenth. The combination of the keys F, F, and F³, with the electro-
magnets S, S2, and S³, circuit breaking lever K, and local battery L,
whereby the sending local circuit is extended from the main to one or
more branch offices, substantially as and for the purpose herein
specified.
Fourteenth. The combination of the relay M, local battery 1, receiving
sounders R, R², and R³, whereby the receiving local circuit is extended
from the main to one or more branch offices, substantially as herein
specified.
Fifteenth. The combination of magnets, keys, or circuit breakers and
conductors for enabling way stations to communicate with terminal
stations, substantially as herein described and illustrated by Figure 13
of the Drawings.
Sixteenth. The arrangement of circuits, substantially as herein
described and illustrated by Figure 12 of the Drawings.
In testimony whereof, I, the said Joseph Barker Stearns, have
hereunto set my hand and seal, this Seventeenth day of October,
in the year of our Lord 1872.
JOSEPH BARKER STEARNS. (L.S.)
Witness,
M. M. LIVINGSTON,
7, Warren St.,
New York City, U.S.A.