IMPROVEMENTS IN ELECTRIC TELEGRAPH PROVISIONAL SPECIFICATION
Year: 1875

page_text: LETTERS PATENT to Sir James Anderson, Knight, of 66, Old Broad
Street, in the City of London, Edward Bull, Electrician, and
George Oscar Spratt, both of Porthcurno, in the County of
Cornwall, for the Invention of "IMPROVEMENTS IN ELECTRIC TELEGRAPH
PROVISIONAL SPECIFICATION left by the said Sir James Anderson,
Edward Bull, and George Oscar Spratt at the Office of the Com-
missioners of Patents, with their Petition, on the 12th August
1873.
We, Sir JAMES ANDERSON, Knight, of 66, Old Broad Street, in the
City of London, EDWARD BULL, Electrician, and GEORGE OSCAR
SPRATT, both of Porthcurno, in the County of Cornwall, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN ELECTRIC
TELEGRAPH APPARATUS," to be as follows:-
This Invention has for its object improvements in electric telegraph

page_text: Our improvements relate to the apparatus by which telegraphic
signals are transmitted, thereby increasing the speed and diminishing
the risk of error.
The special object of this Invention is to produce an instrument which
may be worked with very weak currents, and at the same time be
capable of closing local circuits for the purposes of translation. It
claims to overcome the difficulty hitherto experienced in so arranging a
receiving apparatus that it will respond to currents of exceedingly low
power and effect the transmission of signals to a station or stations
beyond. To attain this, double sets of electro-magnets or polarized
electro-magnets "of somewhat high resistance" are employed with two
tongues fixed (on pivots or in sockets, or suspended by fibres or other
light mcans) in a horizontal or other position at right angles with the
poles of the electro-magnets.
The extremity of one of the tongues is fork-shaped, one leg of the
fork being in connection with the tongue itself, and the other being
insulated from it. The two forks of this tongue are in connection with
the translation and recording apparatus (described farther on). The
other tongue, the free end of which works between the forks of the
tongue above described, and on which are fitted springs or platinum
points for the purpose of making contact with either of the inner sides
of the fork is in connection with one pole of the local battery.
The coils of the electro-magnets are so arranged that when a current
passes through them the tongues move in inverse direction; thus the
connecting points or springs of the tongue joined to the local battery are
pressed to either side of the fork according to the nature of the current
flowing, whether positive or negative. In this arrangement exists the
chief feature of the Invention, as the inverse motion of the tongues
admits of contact being made with the smallest possible range or
"play," and as the tongues themselves carry the local contacts the
translating circuit is at once closed. On either side of the tongues are
fixed small wire or other springs adjustable with fine screws to control
the movements of the tongues and to prevent undue attraction (resulting
from rise and fall of potential) towards either of the poles of the electro-
magnets.

page_text: same time to insure the discs running at equal speed and as nearly as
possible on the same axis.
The ends of the armatures are each provided with two platinum
contact pieces insulated from each other, one (underneath the armature)
being in connection with the line, and the other (above the armature)
in connection with the carth.
For translation the pieces 2 and 3, 4 and 5 of the translating com-
mutator (Y) shewn in the Drawing hereunto annexed should be plugged
together, the switchess and s¹ being turned to the left or "to receive."
The current from, say, the down line, will then enter at the line
terminal (a¹) of the switch s¹, passing down the "tumbler" to contact (b),
from which it passes to relay (R') through condenser and on to the
pieces 2 and 3 of commutator (Y), from whence it passes to earth by
the upper contacts of the two armatures (c, c,) of the translator (T).
In traversing the coils of relay (R¹) the down station's current
alternately closes and opens the local circuit through translator (T¹) by
the attraction of the tongues (d', d¹). By the depression of either of the
translating armatures (d, d,) the "up" line is removed from the carth,
and the translating battery current flows through the battery contact
points (e¹, e¹) to contact (b) of the switch s and thus to the up line, the
battery being "earthed" at its centre alternate currents are transmitted.
In order that the translating station may work to either the up or
down station, the translation may be discontinued, and the sending
apparatus brought into circuit by removing the plugs from pieces 2
and 3, 4 and 5 of the commutator (Y), and inserting them between 1
and 2,-1 and 4.
The advantage, especially on submarine lines, possessed by this kind
of recorder over the usual "Morse" system, exists in the fact that it can
be worked with the ordinary submarine reversing keys, doing away with
the "dashes" and consequent surcharge of cable.
The signals are so formed that an omission or loss of signal is at once
detected by the space which it should occupy on the slip.
Another great point in its favor is that the length or duration of a
single signal is of no consequence. Unlike the " Morse," where a long
dot" may be read as a "dash," or a short "dash" as a "dot signal,
65
"

page_text: this arrangement gives each signal distinct from the others independently
of its length or duration, thus overcoming any cause for doubt or
hesitation resulting from variation of the line.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sir James Anderson, Edward Bull, and George
Oscar Spratt in the Great Seal Patent Office on the 12th February
1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, Sir JAMES
ANDERSON, Knight, of 66, Old Broad Street, in the City of London,
EDWARD BULL, Electrician, and GEORGE OSCAR SPRATT, both of
Porthcurno, in the County of Cornwall, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of August, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said Sir James Anderson, Edward
Bull, and George Oscar Spratt, Her special license that we, the said
Sir James Anderson, Edward Bull, and George Oscar Spratt, our exe-
cutors, administrators, and assigns, or such others as we, the said
Sir James Anderson, Edward Bull, and George Oscar Spratt, our exe-
cutors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS," upon the condition
(amongst others) that we, the said Sir James Anderson, Edward Bull,
and George Oscar Spratt, our executors or administrators, by an
instrument in writing under our or their hands and scals, or under the
hand and seal of one of us or them, should particularly describe and
ascertain the nature of the said Invention, and in what manner the

page_text: same was to be performed, and cause the same to be filed in the Great
Scal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edward Bull, on behalf of myself,
the said Sir James Anderson, and George Oscar Spratt, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
This Invention has for its object improvements in electric telegraph
apparatus.
Our improvements relate to the apparatus by which telegraphic
signals are transmitted, thereby increasing the speed and diminishing
the risk of error.
The special object of this Invention is to produce an instrument
which may be worked with very weak currents, and at the same time be
capable of closing local circuits for the purposes of translation. It
claims to overcome the difficulty hitherto experienced in so arranging a
receiving apparatus that it will respond to currents of exceedingly low
power, and effect the transmission of signals to a station or stations
beyond. To attain this, double sets of electro-magnets or polarised
electro-magnets of somewhat high resistance are employed with two
tongues fixed (on pivots or in sockets, or suspended by fibres or other
light means) in a horizontal or other position at right angles with the
poles of the electro-magnets.
In the plan, Figure 1, a, a, represents the pole pieces of the electro-
magnets; their distance apart can be adjusted by means of right and
left-handed screws, as is shown. The coils of the electro-magnets are
coupled with the cable or land line, which is connected to earth through
these coils. b, b³, are the two tongues turning on pivots at c, c¹.
The extremity of one of the tongues (b) is fork-shaped, one leg of the
fork being in connection with the tongue itself, and the other being
insulated from it. The two forks of this tongue are in connection
respectively with the binding screws d', du, by which they are coupled
with the translating and recording apparatus (described farther on).
The other tongue b, the free end of which works between the forks of

page_text: Dir J. Anderson, Bull, & sprait's improvements in Electric Telegraphs.
the tongue above described, and on which are fitted springs or platinum
points for the purpose of making contact with either of the inner sides
of the fork, is in connection with one, say, the zinc pole of the local
battery.
'The coils of the electro-magnets are so arranged that when a current
passes through them the tongues move in inverse direction; thus the
connecting points or springs of the tongue joined to the local battery
are pressed to either side of the fork, according to the nature of the
current flowing, whether positive or negative. In this arrangement
exists the chief feature of the Invention, as the inverse motion of the
tongues admits of contact being made with the smallest possible range
or "play," and as the tongues themselves carry the local contacts the
translating circuit is at once closed. On either side of the tongues
are fixed small wire or other springs e, e, adjustable with fine screws to
control the movements of the tongues and to prevent undue attraction
(resulting from rise and fall of potential) towards either of the poles of
the electro-magnets.
Figure 1 shows another way in which the controling springs may be
applied.
As a means of further facilitating this adjustment the poles of the
electro-magnets are moved as already explained by a gradual screw
arrangement instead of in the ordinary way.
Figure 1 is a modified form of the tongues shown at b, b', in Figure 1.
In this arrangement (Figure 1) the thin parts of the tongues consist of
pieces of sheet aluminium or other flexible metal. The ends of the
tongues are secured by the binding screw c between two pieces of an
insulating substance, but the ends do not touch each other. The forks
on the right-hand tongue b¹ are considerably longer than in Figure 1,
in fact, are of sufficient length to make a contact in about the middle
of flexible part of the tongue b. The contact screws complete the local
circuit.
The forks on tongue 6¹ may be made of thin brass or other light but
non-flexible metal; oue of them is insulated from the tongue b².
Provision is made for the insertion of condenser capacity (to be varied
as necessary) between the two sets of electro-magnetic coils.

page_text: The position of the condensers with regard to the electro-magnets may
be varied; we use them in the centre for preference.
In order to vary the relation of one set of coils to the other, and when
it is necessary to reduce the sensibility of the relay graduated shunts
can be used.
The tongues above described may be connected to the magnets or
indicators of ordinary galvanometer relays, or may be otherwise
electrically actuated in place of by means of electro-magnets.
For translation, an instrument which records a modification of the
Morse signals somewhat after the manner of Steinheil's code is used. A
plan of a portion of the instrument is shewn at Fig. 2.
Two sets of ordinary "Morse" coils a, a, are employed with two
printing beams b, b', worked on pivots c, c, in the usual manner. The
coils a, a¹, are each at one extremity connected with the copper pole of
the local battery, and at the other they are connected respectively to
the binding screws d', d", Figure 1. The printing beams b, b', carry
small marking wheels d, d, to mark with ink in the well-known
manner on a travelling strip of paper. These marking wheels both
receive the necessary rotary motion from the same driving pinion e.
In place of the disc spindle in general use we provide a small cone-
shaped tube f, the smaller end of which is fixed by an union or flexible
joint to the driving pinion e of the Morse machine. To the larger end
of this tube is attached, permanently or otherwise, one of the printing
discs d. At the smaller end of the conical tube and inside is attached,
so as to admit of the requisite flexibility, a small spindle, the diameter of
which is about one-quarter that of the outer or larger end of the tube,
and the length of which exceeds that of the tube by about one-half or five-
eighths of an inch. To the end of this spindle is attached by a siding
arrangement the second printing disc d*. The second disc is moveable so
as to admit of the width of the printing marks being regulated if necessary.
The object of the tube is to allow the second spindle and disc to write
freely without interfering with the tube disc, and at the same time to
ensure the discs running at equal speed and as nearly as possible in the
same axial line.
The ends of the armature levers are, as is shewn at Fig. 3, each pro-

page_text: (underneath the armature lever) being in connection with the line and
making a battery contact when the armature is attracted, and the other
(above the armature) making an earth connection when both armatures
are away from the magnets. Fig. 4 shews a general plan of the
apparatus.
For translation the pieces 2 and 3, 4 and 5 of the translating com-
mutator Y should be plugged together, the switches S and S¹ being
turned to the left or "to receive" so as to disconnect the finger keys.
The current from, say, the down line will then enter at the line
terminal a¹ of the switch S' passing down the "tumbler" to contact b¹,
from which it passes to relay R' through condenser and on to the
pieces 2 and 3 of commutator Y, from whence it passes to earth by the
upper contacts of the two armatures c, c, of the translator T.
In traversing the coils of relay R₁ the down station's current alter-
nately closes and opens the local circuit through translator T¹ by the
attraction of the tongues d', d. By the depression of either of the
translating armatures d, d, the "up" line is removed from the earth
and the translating battery current flows through the battery contact
points c¹, e¹, to contact of the switch S, and thus to the up lines, the
battery being "earthed" at its centre alternate currents are transmitted.
In order that the translating station may work to either the up or
down station the translation may be discontinued and the sending
apparatus brought into circuit by removing the plugs from pieces 2 and 3,
4 and 5 of the commutator Y and inserting them between 1 and 2,
1 and 4.
The advantage, especially on submarine lines, possessed by this kind
of recorder over the usual "Morse" system, exists in the fact that it can
be worked with the ordinary submarine reversing keys, doing away with
the "dashes" and consequent surcharge of cable.
The signals are so formed that an omission or loss of signal is at once
detected by the space which it should occupy on the slip.
Another great point in its favour is that the length or duration of a
single signal is of no consequence. Unlike the "Morse" where a long
"dot" may be read as a "dash," or a short "dash" as a
dot" signal,
this arrangement gives each signal distinct from the others independently

page_text: of its length or duration, thus overcoming any cause for doubt or
hesitation resulting from variation of the line.
For the more regular and distinct record of signals an automatic
sender will be used.
Having thus described the nature of our said Invention and the
manner of performing the same, we would have it understood that we
claim,―
First. The receiving apparatus or relay making contacts by the inverse
motion of two tongues, substantially as described.
Second. The translating apparatus recording in two lines on a 1
travelling paper the positive and negative signals received through a
cable or land line, and retransmitting corresponding positive and negative
signals through another section of cable or land line, substantially as
described.
Third. The general arrangement of electric telegraph apparatus, sub- 1
stantially as described.
In witness whereof, I, the said Edward Bull, have hereunto set
my hand and seal, this Eleventh day of February, in the year
of our Lord One thousand eight hundred and seventy-six.
EDWARD BULL.
(L.S.)