IMPROVEMENTS IN APPARATUS FOR PRODUCING INDUCED CURRENTS OF ELECTRICITY, SUCH IMPROVED APPARATUS BEING ESPECIALLY APPLICABLE TO TRANSMITTING SIGNALS AND TO CALLING THE ATTENTION OF PERSONS USING ELECTRICAL TELEPHONES."
Year: 1878

page_text: LETTERS PATENT to Arthur French St. George, of Redhill, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN APPARATUS FOR PRODUCING
INDUCED CURRENTS OF ELECTRICITY, SUCH IMPROVED APPARATUS BEING
ESPECIALLY APPLICABLE TO TRANSMITTING SIGNALS AND TO CALLING THE
ATTENTION OF PERSONS USING ELECTRICAL TELEPHONES."
PROVISIONAL SPECIFICATION left by the said Arthur French St. George at
the Office of the Commissioners of Patents on the 1st June 1878.
ARTHUR FRENCH ST. GEORGE, of Redhill, in the County of Surrey. "IMPROVE-
MENTS IN APPARATUS FOR PRODUCING INDUCED CURRENTS OF ELECTRICITY, SUCH
IMPROVED APPARATUS BEING ESPECIALLY APPLICABLE TO TRANSMITTING SIGNALS
AND TO CALLING THE ATTENTION OF PERSONS USING ELECTRICAL TELEPHONES."
My Invention relates to improvements in apparatus for producing induced
currents of electricity, which currents may be used for various purposes in the
ordinary well understood way, and are applicable more especially to the production
or transmission of signals by means of electric telephones, in which a disc or plate
is made to vibrate audibly, and to calling the attention of persons using such tele-
phones to them by means of audible signals.
Round one pole or extremity of a bar magnet I arrange a reel or bobbin, pre-
ferably of a form elongated considerably as compared with its diameter, and round
this bobbin I wind a sufficient length of insulated metallic wire of small diameter.
Outside the coil of fine insulated wire thus formed I wind a second coil of insulated
metallic wire of greater thickness than that forming the first coil, the wire in the
outer coil being preferably about three times the thickness of that in the inner coil.
Through this outer coil of thick insulated wire I pass a current of electricity
generated by a sufficient number of "Leclanchè" cells or other suitable battery,
and a primary external coil is thus constituted, the ends of the wires from which,

page_text: after passing through the battery, are connected together. At the part of the
circuit thus formed, where the operator is situated, I arrange an apparatus by which
the circuit can be rapidly broken and reformed, consisting of a flexible metallic
spring, made to vibrate against a metallic stop by "twitching" or moving it with
the finger, one wire of the circuit being connected with the spring, and the other
with the metallic stop, against which it vibrates, and at each such vibration an
induced current is produced in the inner or secondary coil.
By this improved arrangement of apparatus for producing an induced or
secondary current a large extent of the secondary inner coil of the wire is affected
by a surface, correspondingly large, of the primary or outer coil of thick wire as
compared with the method of construction heretofore ordinarily used, in which the
relative position of the two coils is the reverse of that described.
Where my improved apparatus is to be used for the purpose of calling the
attention of persons to whom signals are to be transmitted through telephones, in
which a plate of metal is made to vibrate audibly, I arrange such a vibrating plate
in the well understood way opposite to the pole of the magnet, arranged as above
described, and when it is desired to call attention to the telephones I cause the
flexible spring to vibrate as described by twitching or moving it with the finger, and
the interrupted current of electricity thus made to pass through the outer or thick
primary insulated wire causes corresponding induced currents of electricity of very
high tension to pass through the inner or thin secondary insulated wire round the
magnet, and a sharp sound is thus made by the vibrating metallic plate at each
vibration of the spring, the sound being sufficiently loud to be heard at a con-
siderable distance, and thus call the attention of the person who is to receive the
signals, which are transmitted in the usual way.
The ends of the inner thin secondary insulated wire may be conveyed to any
required distance, and may be connected to corresponding coils of insulated wire
round as many telephones as it may be desired to have, in different positions in the
circuit (which may be completed through the earth). Any or all of these tele-
phones may have an outer or primary coil of thick insulated wire wound round
their inner coil, and connected with a battery and flexible spring, as above described,
so that either operator may call attention to all the telephones in the circuit at any
time.
My improved method of construction and arrangement, as described, obviates
the necessity of a "switch" or its equivalent, as in methods heretofore used,
worked by an automatic arrangement of springs and contact pieces, or by hand,
in order to throw the telephones off the lines of communicating wires before an
electric battery and electric bell, or a magneto-electric call bell, can be introduced
into the circuit to call attention by touching a press button, plunger, or key, or
revolving a magneto-electric machine, so as to pass a circnit of electricity through
such bell, and great simplicity and certainty of action are thus obtained, and no
disturbance or interference with the voice or sounds transmitted through the
ordinary telephone is produced, the insulated wire coils of the latter always
remaining in the line circuit.
The loud sounds produced, as described, by moving the flexible spring in the
circuit of the outer primary coil and battery may themselves be used as signals by
arranging a suitable code.
If a horse-shoe magnet be used the coils described may be arranged upon one or
both poles of such magnet, and any convenient form of telephone may be used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Arthur French St. George in the Great Seal Patent Office on the 30th
November 1878.
ARTHUR FRENCH ST. GEORGE, of Redhill, in the County of Surrey. "IMPROVE-
MENTS IN APPARATUS FOR PRODUCING INDUCED CURRENTS OF ELECTRICITY, SUCH
IMPROVED APPARATUS BEING ESPECIALLY APPLICABLE TO TRANSMITTING SIGNALS
AND TO CALLING THE ATTENTION OF PERSONS USING ELECTRICAL TELEPHONES."
This Invention relates to improvements in apparatus for producing induced
currents of electricity, which currents are applicable more especially to the pro-
duction or transmission of signals by means of electrical telephones, in which a disc
or plate is made to vibrate audibly, and to calling the attention of persons using
such telephones to them by means of audible signals, but they may also be used for
other purposes in the ordinary well understood way.
In order to put my Pivention in operation I take a bar magnet, and round one
of its poles or extremities I arrange and fix a reel or bobbin of wood or other
suitable material, and round this reel I wind a sufficient length of insulated metallic
wire of small diameter. Outside the coil of thin insulated wire thus formed I wind
a second or outer coil of insulated metallic wire, preferably of greater thickness
than that forming the inner coil, the wire in the outer coil being preferably about
three times the thickness of that in the inner coil, though these relative proportions
may be varied. Through the outer coil of thick insulated metallic wire, arranged
as described, I pass a current of electricity, generated by a sufficient number of
Leclanché" cells or other suitable battery or apparatus, and a primary outer or
external coil is thus constituted, the end of the wires from which after passing
through the battery are connected together. At a part of the circuit thus formed,
where the operator is situated, I arrange an apparatus by which the circuit can be
rapidly made and broken, consisting preferably of a flexible metallic spring made to
vibrate against a metallic stop by "twitching or moving it with the finger, one
wire of the circuit being connected to the metallic spring and the other to the
metallic stop, against which it vibrates, and at each such vibration an induced
current of electricity is produced in the inner or secondary coil of wire.
"
ور
Instead of the vibrating spring being set in motion when desired by the finger,
as described, it may be made to vibrate by means of a small electro-magnet, or by
any other convenient means.
By the improved arrangement of apparatus above described for producing an
induced or secondary current a large extent of the secondary inner coil of insulated
wire is influenced by a surface, correspondingly large, of the primary or outer coil
of insulated wire, as compared with the method of arrangement heretofore ordinarily
used, in which the relative position of the two coils of insulated wire is the reverse
of that described.
Where my improved apparatus is to be used for the purpose of calling the
attention of persons to whom signals are to be transmitted through telephones, in
which a plate or disc is made to vibrate audibly, I arrange such a vibrating plate
in the well understood way opposite to the pole of the magnet, arranged as first
above described, and when it is desired to call attention to the several telephones in-
the line I cause the flexible spring to vibrate in the way already described, and the
rapidly interrupted current of electricity, which is made by this means to pass
through the outer primary coil of insulated wire, causes corresponding induced.
currents of electricity to pass through the inner secondary coil of insulated wire,
which is arranged round the magnet, and a sharp sound is thus produced at each
vibration of the spring, and consequent interruption of the currents, the sounds
being sufficiently loud to be heard at a considerable distance, and thus call the
attention of the person who is to receive the signals, which are then transmitted in.
the usual way.
:

page_text: Instead of a bar magnet in the coils I sometimes use a bar of soft iron, or a
bundle of soft iron wires.
The ends of the inner secondary insulated wire may be conveyed to any required
distance, and may be connected to corresponding coils of insulated wire round as
many telephones as it may be desired to have in different positions in the circuit,
which may be completed through the earth instead of through a return wire. Any
or all of the telephones thus included in the circuit may have an outer coil of insu-
lated metallic wire wound round the inner coil, and connected with a battery and
flexible spring or other apparatus for rapidly making and breaking the electrical
circuit, as already described, so that either operator may call attention to all the
other telephones in the line circuit at any time.
The accompanying Drawing is in illustration of my Invention.
Figure 1 shews in cross section the arrangement of coils just described, a, a, being
the outer primary coil of thick insulated wire, and b, b, the inner secondary coil of
thin insulated wire.
Figure 2 shews the ordinary method of arrangement, in which the primary coil
of thick insulated wire a, a, is inside the secondary coil of thin insulated wire b, b,
and it will be seen that in my improved method of arrangement, as shewn in
Figure 1, a large extent of secondary thin wire is exposed to a similarly large extent
of primary thick wire, as compared with the arrangement shewn in Figure 2, the
relative position of the two coils being reversed.
If a horse-shoe bar be used the coils may be arranged upon both poles of
such bar.
Figure 3 shews in horizontal section the improved arrangement of coils applied
to the purpose of transmitting signals through ordinary telephones, or calling the
attention of persons using such telephones.
a, a, is the primary outer coil of insulated wire, and b, b, the inner secondary
coil, arranged, as described, round the magnetic bar c. The vibrating plate d is
adjusted opposite to the end of c, and e is the mouth-piece or ear-piece for speaking
or hearing through the telephone, which is thus formed:-One wire a¹ from the
primary coil passes to the electrical battery f, and thence is put in metallic con-
nection with the adjustable stop or screw g, the point of which is nearly in contact
with the flexible metallic spring h, which is in metallic connection with the other
wire all of the primary coil. When the spring his vibrated by twitching it with
the finger of the operator against the projection i upon it an interrupted current of
electricity is produced. through the battery and coil, and at every interruption or
vibration an induced current of electricity of high tension is produced in the
secondary inner coil, and a sound is emitted from the plate d, sufficiently loud to
be heard at a considerable distance, and thus call attention at once to the instru-
ment. The ends b', 6, of the inner coil may be conveyed to a distance and con-
nected to a corresponding coil of insulated wire round as many telephones as it may
be desired to have in different positions in the circuit. Or one of the wires may
be connected with the earth, through which the circuit is thus completed. Any or
all of the telephones may have an outer or primary coil of insulated wire, as well
as the inner one, such primary coil being connected with a battery (the wire from
which may be divided, a part being taken to each such coil) and flexible spring,
as above described, so that either operator may call attention to all the telephones
in the circuit at any time.
Instead of the vibrating spring moved by the finger, as described, an ordinary
self-acting contact breaker may be used for causing the interrupted current in the
primary coil, such device being put in operation when desired by connecting its
wires to those of the battery; or a plate vibrated by sound may be used for the
same purpose.
My improved arrangement of apparatus, as above described, prevents the
necessity (as in methods heretofore used) of a "switch" or its equivalent, worked
by an automatic arrangement of springs and contact pieces, or by hand, in order to
throw the telephones off the line wires before an electric battery and call bell; or a.

page_text: magneto-electric call bell can be introduced into the circuit to call attention by
touching a press button, plunger, or key, or by revolving an electro-magnetic
machine so as to press a current of electricity through such bell apparatus. Great
simplicity and certainty of action are thus obtained, and no disturbance or inter-
ference with the voice or sounds transmitted through the ordinary telephone is
produced, the insulated wire coils of the latter always remaining in the line
circuit.
The loud sounds produced, as above described, by causing interrupted currents in
the circuit of the primary coil and battery may themselves be used as signals by
arranging a suitable code.
Any convenient form of telephone inay be used.
Having now described my Invention and the manner in which it is to be per-
formed, I claim,-
The construction of apparatus for producing induced currents of electricity by
means of a primary coil of insulated wire surrounding a secondary coil of insulated
wire, an interrupted current of electricity being passed through the outer coil, sub-
stantially as described, and shewn in the Drawing.
Also the apparatus consisting of a primary coil of insulated wire surrounding the
ordinary coil of insulated wire in a telephone, in combination with a device for
passing an intermittent current of electricity through the primary coil when desired,
for the purpose of producing a series of loud sounds from the vibrating plates of all
the telephones in the circuit, and thus calling attention to the latter, substantially
as described, and shewn in the Drawing.
In witness whereof, I, the said Arthur French St. George, have hereunto set
my hand and seal, this Thirtieth day of November, in the year of our
Lord One thousand eight hundred and seventy-eight.
ARTHUR FRENCH ST. GEORGE.
(L.S.)