IMPROVEMENTS IN TELEGRAPHIC AND TELEPHONIC APPARATUS A
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the Firm of Haseltine, Lake
"
& Co Patent Agents Southampton Buildings London for an invention
of "IMPROVEMENTS IN TELEGRAPHIC AND TELEPHONIC APPARATUS
A com-
munication to him from abroad by François van Rysselberghe of Schaerbeck,
Belcium
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 24th May 1882.
WILLIAM ROBERT LAKE, of the firm of Haseltine Lake and Co Patent
Agents, Southampton Buildings, London "IMPROVEMENTS IN TELEGRAPHIC AND
TELEPHONIC APPARATUS [A communication to me from abroad by François van
Rysselberghe of Schaerbeck, Belgium.]
"
This invention relates to apparatus whereby telephonic and telegraphic messages
may be transmitted simultaneously, through the same wire,
"
"
The currents employed for electric communication may be divided into three
classes viz;-Currents of a certain duration, such as those used for operating the
Morse" telegraph; instantaneous currents, such as those utilized for the "Hughes
telegraph; and undulatory or wave-like currents such as those employed for
operating harmonic telegraphs and telephones.
of
In the accompanying drawing let M be a manipulator of any kind for currents
of a certain duration or by preference a device for making and breaking contact in
the case of a gradual current. Also let P be a battery, C a condenser, B' a receiver
any kind for currents of a certain duration, B and B³ a receiver and a transmitter
of undulatory or wave-like currents, B* a suitable resistance-coil or the like, if such
be necessary, and a line wire connecting one station thus fitted up, with another
station fitted up in a similar manner. By this means it is possible to employ for
telephonic communication or for harmonic telegraphy a wire in full use for
telegraphing by means of currents of a certain duration or by means of instan-
taneous currents which has not heretofore been practicable. All the devices above

page_text: mentioned are not indispensable, and they may be modified if desired; thus in
certain cases the resistance B will not be necessary, in other cases the condenser C
may be dispensed with; a commutator may also be employed for putting out of
circuit during transmission, the receiver B² and during reception, the transmitter B³;
or these two latter devices may be placed in derived circuits.
The said invention allows of messages being sent by means of currents of a
certain duration or by means of instantaneous currents at the same time that
messages are sent by means of undulatory or wave-like currents and by the
same wire.
In the circuit in which the receiver B2 and transmitter B³ are placed a coil may
be inserted induced by the resistance B4 and constructed in such a manner as to
annul the instantaneous current which passes towards the said condenser C at each
completion of the circuit by M.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
24th November 1882.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake and Co Patent
Agents, Southampton Buildings, London, " IMPROVEMENTS IN TELEGRAPHIC AND
TELEPHONIC APPARATUS A communication to me from abroad by François van
Rysselberghe, of Schaerbeck, Belgium,
د"
This invention consists in a combination of telegraphic and telephonic apparatus
in which ordinary telegrams by the Morse, Hughes, Wheatstone or other apparatus,
and telephonic conversations, can simultaneously pass on the same line-wire.
And the invention admits of the ordinary telegraph office being kept entirely
independent of, and distinct from, the telephonic-office.
The separation of the currents of ordinary telegraphy from the undulatory
currents of telephony is effected by means of electrical induction produced without
putting the telephonic circuit in metallic or conductive contact with the ordinary
telegraphic circuit; the two circuits being so far independent of one another,
It is essential, that the telegraphic currents should be gradually produced and
extinguished and should not be the instantaneous currents which result from the
ordinary opening and closing of a battery circuit without precaution,
And it is also essential that the line-wire should not be connected with the
earth otherwise than through a somewhat high resistance,
Figure 1 indicates the arrangement in the case where the separation of the
currents is produced by induction in coiled wires,
Figure 2 shews the same system acting by induction in condensers,
In Figure 1, L is a line-wire; the arrangements at both ends of this line-wire
are similar to those which the figure indicates.
A is an induction-coil with an iron core, the primary wire of the coil serves as a
connection between the line L and the terminal branch line T, B, which leads to
the telegraph office; the secondary wire of the same coil serves as a connection
between the earth and the terminal branch line C, S, which leads to the telephonic
office. In each of these two offices the apparatus may be arranged in the ordinary
manner. The telegraphic branch line T, B, must never be insulated from the earth
at the telegraphic office,
Dimensions which have been found suitable for the induction-coil A are
Diameter of iron core 10 m. m
Length
"
50
"
"
" "
500 Ohms
Resistance of the primary wire
"
"
"
Secondary wire 100
"
This induction-coil with its iron core and high resistance in the primary wire

page_text: electro-magnet which offers a resistance of 500 ohms or more. If the condenser A
have a capacity of 1 microfarad it will be found suitable. The best arrangement
of the telegraphic apparatus is that indicated in Figure 2 in which R is the
receiver, and the resistance of the electro-magnet of the receiver is always interposed
between the line and the earth. In this case it is the electro-magnet R which
graduates the telegraphic currents entering the line-wire and which also provides
the resistance necessary to the due propagation of the telephonic waves through
the condenser.
If it is desired to retain the usual connections of the telegraphic apparatus, an
electro-magnet K (Figures 3 and 4) of not less than 500 ohms resistance is to be
interposed between the battery and the manipulator, or between the battery and
the earth. The key should be made with spring-contacts. Although in the
telephone office, the apparatus may be arranged in the usual manner, it is never-
theless preferred especially for long distances, to adopt the arrangement indicated
by Figure 5 and characterized by a commutator P (worked by the hand, foot, or
finger) having the same construction as the manipulating key of the Morse
apparatus; the object of this is to put out of circuit, during reception, the
resistance of the transmitter, and during transmission the resistance of the
receiver,
Figure 6 shows a very good arrangement in which an induction-coil is employed;
there is, as will be seen, a condenser in constant connection with the line-wire; the
receiving instrument is introduced between the back contact of the key and the
earth and there is an electro-magnet of 500 ohms resistance between the battery
and the earth connection.
In place of the condenser, a resistance of say 1000 olums may, in this arrangement
be substituted.
Having thus fully described the said invention as communicated to me by my
Foreign correspondent, and the manner of performing the same, I wish it understood
that I Claim :-
The combination and arrangement, substantially as described, with, and upon,
the same line wire, of telegraphic and telephonic apparatus in such manner that
the currents on the line from the telegraphic apparatus are gradually produced and
extinguished, and the connections established by the telegraphic apparatus between
the line and earth are through a somewhat high resistance.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Twenty fourth day of November in the year of our
Lord One thousand eight hundred and eighty two.
117M PORT TATT lol