Improvements in and relating to Multiple Telegraphy.RADIHO TRANS
Year: 1888

page_text: Date of Application, 17th July, 1888
Complete Specification Left, 16th Apr., 1889
Complete Specification Accepted, 8th June, 1889
PROVISIONAL SPECIFICATION.
T
Improvements in and relating to Multiple Telegraphy.
ن
.>
I, ERNEST JULES PIERRE MERCADIER of 1 Boulevard St. Denis Paris France
Electrical Engineer do hereby declare the nature of this invention to be as follows:
This invention is based:
1st.. On the coexistence of the small electric undulations simultaneously occurring
in an aerial, underground, or submarine conductor, and their crossing each other
without confusion, a continuous current or a permanent electrostatic charge having
been previously established in the said conductor.
2nd. On the employment of radiophomic (photic or thermic) transmitters and
microphomic transmitters of novel nature and arrangement.
3rd. On the employment of novel receivers which separate the electric vibrations of
different rhythm.
: t
Its object is to transmit simultaneously through the same line in tho one or the
other direction several signals in accordance with a conventional alphabet.
It comprises two modes of transmission the one teleradiophonic the other telemicro-
phonic, and one mode of reception; these are hereinafter successively described. I
[A] HOTIC LELERADIOPHONIC TRANSMISSION OR
§ 1. TRANSMITTER.
:-
TELEPHOTOPHONE.
In this case the transmitter is composed of 4 parts:-
1st. Optic part. A pencil of parallel luminous rays from any sufficiently intense
source such as an oxyhydrogen lamp or an incandescent or are electric lamp; the
pencil passing through a cylindrical lens produces a rectangular image of about'a
centimetre wide and from 6 to 8 centimetres long.
+

page_text: For
2nd. Interrupter part.-An interrupting wheel of constant speed for producing
intermittences in the luminous pencil according to the different rhythms.
this purpose if it is of metal, say zinc, copper, aluminium &c., it is formed with
several sets of holes of different number; if it is of glass, a disc of thick paper
previously formed with several sets of holes is pasted over it. On a wheel of
55 centimetres diameter there can be seven sets of circular holes of 10 millimetres
diameter the numbers of which are respectively the same as the numbers of the
vibrations of the sounds of a diatonic scale for example Dot, Ret, Mit, Fat, Solt,
Lab, Sit
The result is that the part of the luminous pencil that passes through each set of
holes will be intercepted by the solid parts of the wheel turning at a speed of about
11 revolutions per second according to the rhythm special to each set. This speed
is sufficient to produce in the extreme set which has 95 holes 1045 interruptions per
second. Now Sit corresponds to about 974 vibrations per second.
By giving to the 7 sets respectively the numbers of holes 50, 56, 63, 67, 75, 84
and 95 the sounds of the diatonic scale are very nearly approximated.
For brevity I will call the sets of holes and the luminous rays which traverse them
by the names of the corresponding notes of the scale of the sign; thus set and
ray, Ret; set and ray, Solt, &c.
3rd. Radiophone. An electric radiophone of rectangular form sufficiently large to
receive the 7 rays Dot, Ret, &c. It should have a very great resistance and a
sensitiveness sufficient for the radiations; it is formed of one of the following
bodies selenium, alloy of selenium and tellurium, lamp black, sulphide, iodide,
bromide or chloride of silver, sulphide of tin, sulphide of antimony, galena, oxide
of copper or iron, phosphide of zinc; all but the three first named bodies are new
in the employment for or application to this purpose.
I will describe only the preparation of radiophones formed of selenium, sulphide of
silver and sulphide of tin; the others will be made in a similar manner.
The selenium radiophone is formed of two brass plates two centimetres wide and
from 6 to 10 centimetres long; they are juxtaposed but covered with layers of asbestos
paper which press them against each other and at the same time insulate them. They
are connected together at their ends by 2 ebonite cross pieces. On the asbestos
are wound in close spirals and parallel two wires of platinum, copper, brass or other
metal; the two ends of the one wire are fixed to the one plate and those of the other
wire to the other plate.
Before fixing the ebonite cross pieces the apparatus is heated on a mica plate to a
temperature such that a crayon of selenium placed thereon will begin to melt (about
210° centigrade); the crayon is then rubbed rapidly over the surface of the apparatus
care being taken to well fill the spaces between the 2 wires and to maintain the
temperature; the apparatus is then left to cool so that the selenium surface may
preserve a dark grey color.
By leaving a space of about a milimetre between the 2 wires a radiophone is
obtained which is very sensitive to intense light; its electrical resistance rises
gradually to about 300,000 ohms and afterwards remains constant for several years
withont the apparatus losing its properties. This resistance can be reduced at will by
diminishing the space between the wires.
The sulphide of silver radiophone is formed of wires such as silver, platinum,
aluminium, iron, &c., wound in the same manner upon a layer of sulphide spread first
on an insulating plate of asbestos cork or mica in the form of a convex cylinder.
The wires pass round 2 ebonite plates which can be separated from each other by
2 screws; this allows (and this is a very important point) of varying as required the
pressure of the wires on the layer of sulphide. These wires terminate as do those of
the radiophone previously described at two insulated binding screws. The layer
of sulphide of silver can be produced by taking a silver plate, sprinkling it with flour
of sulphur and heating gently underneath through a mica plate and then slowly
evaporating the excess sulphur; or it can be produced by electrolysis.

page_text: The appropriate resistance is obtained by varying the thickness of the layer of
sulphide, the pressure, and the space between the z wires.
Radiophones of iodide, bromide and chloride of silver melted can be made in the
It is the same with selenium which can be melted and spread upon an
insulating surface and afterwards wound with a double helix of wires.
same manner.
It is also the same with sulphide of tin and generally with the hard bodies among
those hereinbefore named with this difference that these can be set in sealing wax and
filed at the surface.
4th. Manipulator. Manipulators of a number equal to that of the sets of holes in
the revolving wheel. A thin rod of aluminium about 10 centimetres long carries a
diaphragm or disc about 1 centimetre square; it can move upon a centre under the
action of an electro magnet on an armature abont 1 to 2 centimetres long on the
end of the rod and which is capable of moving a distance of 2 to 3 millimetres
between the core of the electro-magnet and a stop which as well as a counter-
spring is carried by a bracket adjoining the electro-magnet. The electro-magnet is
incited from a distance by means of a battery and a suitable manipulator, a Morse
manipulator for example.
Seven similar electro magnets and rods are fixed on the table which supports the
shaft of the revolving wheel in such manner that in the state of rest the diaphragms
arrest the rays Dot, Ret, &c. In order that one of them, Solt for example, may
pass through the wheel and fall on the radiophone it is necessary to work that one
of the 7 manipulators which corresponds to the electro magnet of the rod and
diaphragm appertaining to the set Sol.
For brevity each manipulator as well as the electro magnets, rods, diaphragms,
sets of holes and luminous rays which pass through them can be called by the
denominations Dot, Ret, &c.
In one position the diaphragms close the holes situated in a plane passing through
the ends of a horizontal diameter; this constitutes for the electro magnets and the
diaphragın rods a simple arrangement.
The arrangement of the manipulators as above described is not indispensable ;
any other means whereby the luminous rays are allowed to pass in accordance with a
given rhythm would answer.
The transmitter having been thus arranged, let us suppose a circuit comprising a
battery, the radiophone, and an ordinary telephone, the interrupting wheel turning
with a speed of about 11 revolutions per second rendered constant by the means
hereinafter described. If the hand be pressed on manipulator Mit, for example, the
set of holes Min will be uncovered and according to the laws of the radiophone
continuous sound Mit, will be heard in the telephone. Should the manipulator
produce Morse signals for example these signals will be perceptible to the ear at the
telephone just as experienced telegraphists understand Morse signals by simply
listening to the rhythmic sound produced by the pallet of the electro magnet of the
apparatus against the stops, or rather just as the same telegraphists perceive with
the eye the signals of optic telegraphy, the manipulation being the same in both
cases.
If instead of only one manipulator the 7 manipulators are operated the ear will
hear in the telephone simultaneously the 7 kinds of signals which are simply
superposed, each of them preserving its individuality and without their affecting each
other. Further on is described how by means of special receivers this superposition.
can be avoided and each kind of signals can be distinctly isolated from the others.
Speed Regulator. But the putting of the transmitter into action supposes, as I
have above stated, that the speed of the interrupting wheel is constant I will now
describe how this constancy is produced, established and maintained.
The interrupting wheel is put in motion by means of a cord passed over a
pulley on its shaft and over another pulley fixed on the shaft of a small electric motor.
This motor is actuated by a battery as constant as possible, for example a Clamond
thermo electric battery heated by means of a constant current of gas; an ampere
meter and a rheotstat are introduced into the circuit of the battery and motor

page_text: wire... The desired speed of the wheel is thereby produced. Any other motor having
a sufficiently precise regulation of speed can be employed.
This speed is established by an acoustic process. For this purpose a caoutchouc
tube of a length calculated to raise the sound Sit has one of its ends placed some
millimetres from the projection formed by the holes of the set Sit; the impact
of the air drawn.. through each hole over the edges of the tube produces the
sound Sit by mechanisin analagous to that of the acoustic instrument known as
the Sirene. The other end of the tube is placed inside the sound box of an electro
diapason Sit the movement of which is maintained electrically-by means of one or
two Daniell elements. The result is that when the speed of the wheel progressively
increases the sound produced by the tube rises; when it approaches Sit there are
heard the beats produced by the sound of the tube and that of the electro diapason.
When the beats cease the two sounds are identical and the speed of the wheel is
appropriate; the absence of beat establishes this A sound can be produced with the
projections of the holes in the wheel otherwise than by a tube; it suffices for example
to. rub a piece of paper over these holes. In short it is sufficient to produce in any
manner a sound characteristic of the speed of the wheel.
In order to maintain this speed it is sufficient to maintain this absence of beat, or
rather to constantly maintain one or two beats per second. This object is attained by
means of a rheostat which allows of varying the battery current and consequently the
speed of the motor and of the wheel. The sensitiveness of this regulation is obvious;
the. number of beats per second being equal to the difference between the numbers
of the vibrations of the sounds of the tube and of the electro diapason, and this
latter making about 974 complete vibrations per second, by maintaining this difference
at nearly one beat per second which every one can estimate, the speed of the wheel
is certain to be maintained constant at nearly 14..
For brevity I will give the name of acoustic tachymeter to this combination of the
tube or any other device which allows of producing a sound characteristic of the speed
of a wheel and of the electro diapason furnished with its sound box, the whole
intended to establish and to estimate at about the variations of speed of a revolving
wheel above or below a given speed and this without sensibly affecting this speed
itself.
§ 2. RECEIVER.
Multiple effect monotelephone. The receiver is a monotelephone or an electro
magnetic sounder. It is a telephone the diaphragm of which, circular or rectangular,
is not held at the edges; if it is circular it is placed upon points forming the
apices of an equilateral triangle drawn in the circumference constituting the nodal
line of the first harmonic; if it is rectangular it is placed on the 2 nodal lines of
the fundamental sound at 2 of the length reckoning from the ends.
If a set of undulatory currents of different rhythms be passed into the coil of the
apparatus which has a resistance of 300 or 400 ohms a diaphragm vibrates in an
appreciable manner only under the action of the currents the vibratory period of
which is equal to that of the 1st harmonic of the diaphragm, if it is circular, and to
that of the fundamental sound if it is rectangular. This is the characteristic property
of the apparatus.
In the circular monotelephone the diaphragm is placed on 3 points movable along
graduated slides fixed to a platform. A cover has a ceutral socket to which is fitted a
caoutchouc tube provided with a mouth piece for receiving the sounds from the
stratum of air above the diaphragın. A second similar tube fitted. to a metal tube
which: terminates above the platform as close as possible to the pole of the electro
magnet collects the vibrations of air below the diaphragm; the result is that by
applying to the ears the mouthpieces of the tubes, which can be kept there by means
of leathern straps fitted to the head of the person who listens, he will hear 2
identical sounds when the diaphragm vibrates in such manner that the apparatus is
thus of double effect and that the listener is screened from external noises and has.
both hands free.

page_text: Regulation. The apparatus is further provided with means for regulating it. A
small brass cylinder or weight can slide along a radius of the diaphragm; for this
purpose it is held on one side by means of a thin slip of caoutchouc and on the
other side by a thread wound over a drum; by turning this the cylinder approaches
more or less to the centre of the diaphragm and its weight causes more or less.
variation in the height of the sound of the diaphragm without preventing its
vibrations. There is thus easily obtained a continuous variation of at least a major
second.
With the assistance of the laws of the vibrations of circular plates diaphragms are
constructed of the same thickness (1 millimetre for example) and of a diameter
calculated so that their first harmonics reproduce all the sounds of the diatonic scale
Do Re, &c.
Monotelephones fitted with these, diaphragms constitute receivers corresponding to
the transmitters of the same name. They are introduced in the circuit comprising
the radiophone of the telegraphic transmitting station and the telegraphic line the
2 ends of this circuit going to earth.
It is therefore seen that if at the transmitting station all the 7 manipulators be
worked at once all the electric undulations resulting therefrom will pass through all
the receivers at the receiving station but only the signals produced by the
manipulator Dot will be heard in the receiver Dot; only the signals from the
manipulator Re in the receiver RE, and so on. The receptions will therefore be
simultaneous and remain independent of each other.
A current of an intensity of 0.00002 of an ampère at most suffices in these instru-
ments to produce by its radiophonic variations sounds sufficiently intense for a good
The telegraphic system to be complete requires that each station shall be able to
transmit or receive at will, and that each operator shall be able to speak at any
moment to his correspondent for rectifications or collations. It is therefore necessary
to have
[a.] At the transmitting station a battery communicating on the one band with
earth and on the other with one of the poles of a radiophone; in front of this
the interrupting wheel provided with its optic system, its motor, its tachymeter, and
its 7 manipulators; 7 monotelephones tuned to the sounds of the diatonic scale
of Do and introduced in the circuit beyond the radiophone. 7 operators are placed
in a room other than that which contains the radiophone, the wheel and its accessories;
each of them is provided with means for holding to his ears the mouthpieces of the
tubes of a monotelephone, and he has under his hand the corresponding manipulator,
that is to say, that which produces the sound for which the monotelephone is
tuned; he therefore hears his own transmission and is always ready to receive that
of his correspondent who manipulates the same sound. The telegraphic line is.
connected to the last monotelephone.
[.] At the receiving station :-An absolutely identical arrangement comprising
7 monotelephones, a radiophone, with final communication to earth, an interrupting
wheel driven at the same speed and having its optic system, motor, tachymeter, and
manipulators. The identity of the monotelephones at the 2 stations is assured, by
their construction, but the means of regulating above described allows of any
constructive defect being remedied and of insuring maximum intensity to the sonorous
signals received. The identity of the speed of the 2 wheels is insured by that of the
électro. diapasons of the tachymeters but the very slight differences which can
arise from the temperature could also be easily corrected by means of the
regulators of the monotelephones. But in order to have more certainty in the
synchronism of the wheels, it is sufficient to fit the electro diapasons with a very light.

page_text: to place at each station one of the 12 monotelephonic receivers above described with
an interrupting wheel having a single set of openings producing the sound to which
the monotelephone is tuned. It should be observed that the aforesaid 12 stations
could communicate not only with the central station but also with each other without
the central station having to give them communication by means of commutators or
other similar appliances. It is sufficient for this 1st that each station should possess a
wheel with 12 sets of openings, 12 manipulators and the 12 corresponding mono-
telephones; 2nd that notice should be given of the station which calls. This notice
would be given by the central station. The station called could then serve to receive
the messages from the monotelephone in unision with that of the temporary corre-
spondent and of the corresponding manipulator for transmitting them.
The intensity of the effects produced in the monotelephone can be increased by
transforming its diaphragm into a microphone; for this purpose it suffices to fix at a
point of the circumference a carbon rod of 1 millimetres diameter and 10 millimetres
long by means of a small loop of aluminium foil, and to place in a notch made in the
rod another rod of 3 millimetres diameter and 30 to 40 millimetres long engaged at
its other end in a hole formed in a small carbon 'block fixed on the platform of the
apparatus. One has only to connect the block on the one hand and the diaphragm on
the other with a battery and the primary wire of the induction coil of an ordinary
microphone; the secondary wire being connected to a telephone, this reproduces the
reinforced sounds of the diaphragm.
[B] THERMIC Teleradiophonic TRANSMISSION OR TELETHERMOMICROPHONE.
The transmitter above described includes a radiophone particularly sensitive to
luminous radiations; it is a photic radiophone or photophone..
A radiophone can be employed principally sensitive to thermic radiations that is to
say a therinic radiophone or thermophone but it is necessary for it to produce electric
undulations in the circuit which it has to work. For this purpose the apparatus is
composed of an ordinary microphone of 8 to 10 centimetres diameter the diaphragm
of which, of wood or metal, supports sufficiently light carbons about 3 millimetres in
diameter and 5 or 6 centimetres long; their ends are connected as usual to the poles
of a microphone battery through the intermediation of the primary wire of an induc-
tion coil the resistance of which is only a few ohms; the secondary wire is very fine;
it is composed of a very great number of turns and therefore offers a great resistance;
it is connected to a line battery (the other pole of which goes to earth), and to the
telegraph line.
The surface of the diaphragm is coated with lamp black and covered with a thin
glass plate forming therewith an enclosed air chamber of only 5 or 6 millimetres deep.
The glass plate is exposed to the intermittent radiations which pass through it and
produce variations of temperature in the layer of air in contact with the lamp. black;
there is consequently a vibratory movement in the body of air in the chamber which
is transmitted to the diaphragm of the microphone; this therefore acts as usual and
produces in the current which passes through the wire and the line electric undulations
of the same rhythın as that of the air chamber. The apparatus is fixed to a support
by means of an elbow joint which allows of the maximum sensitiveness being given to
the microphonic system. I will call this apparatus for brevity the thermomicrophone.
If the telegraphic line has not a great resistance an induction coil suffices and even
this can be dispensed with, the microphone being then connected to the line and to
the battery. If this line and the apparatus which are interposed offer great resistance
the microphone is connected to a set or battery of coils the primary wires and
secondary wires of which can be connected in series or for quantity according to
circumstances, as is ordinarily done with the elements of a battery or pile.
In the preceding apparatus a thin glass plate can be employed for the diaphragm,

page_text: the air chamber can be made with glass sides and instead of the air therein gases or
vapors can be used which energetically absorb the luminous radiations, such as the
vapors of iodine, hyponitric acid &c., the effect of which would be added to the
thermic effect of the lamp black.
Lastly, I can construct, as I have described for the photophone, thermophones with
lamp black, iodide of silver or other substances particularly sensitive to thermic
variations they then act without a microphonic intermediary.
In the case of a thermomicrophonic radiophone transmitter the poles of the radio-
phones are replaced by those of the induction coil or of the battery of induction coils
the one being connected to the monotelephones and the other to the battery and earth.
.
.
The mode of telethermophonic transmission above described can be simplined or
rather transformed in the following manner. I suppress all radiophonic action as well
as the interrupting wheel.
1
Transmitter. I take electro diapasons tuned exactly to the sounds of the chromatic
scale and provided with a sound box. On each of these boxes I fix the apparatus
above described as the thermomicrophone, or even an ordinary microphone, or,
simpler still, I fix the carbons of an ordinary microphone on the upper surface of the
sound box which thus serves as a diaphragm directly acted upon by the vibrations of
the diapason. The primary wires of the induction coils of the 12 microphones instead
of each forming a special circuit including its battery can be connected together
either in series or for quantity in the circuit of a suitable battery. The secondary
wires can be connected together in a manner analogous to that in which the elements
of a battery are connected and terminate at the telegraph line on the one side and at
earth on the other, at the transmitting station. 1 can employ coils 20 centimetres
long and 3 centimetres in diameter for the secondary wires and they can easily be
given a resistance of 5000 to 6000 ohms, and if necessary I can use a battery of coils
of this kind according to the special conditions of the line to be worked. As regards
manipulation this is effected by means of a Morse manipulator for example
introduced into the primary wire of each microphone. The transmitter element thus
constituted can be called a microphonic electro-diapason. But it is evident that I
could employ for causing the microphones to vibrate any other body which vibrates in
a permanent and regular manner, such as a sonorous pipe for example.
Receiver. The receivers are the monotelephones already described. There is
: nothing to change in the mode of reception.
Arrangement of the stations. One of the ends of the secondary wire of the induc-
tion coil or battery of induction coils goes to earth at the transmitting station; the
: other end is connected to the line after having passed through the monotelephones.
At the receiving station the arrangement is the same. All these parts, secondary
wires of the coils and monotelephones, are introduced into the circuit the 2 ends of
which go to earth. As to the exchange of communications between a central station
and several others, the remarks hereinbefore made under § 5 will apply. I will add
that I can introduce a battery into the general circuit.
"
The mode of transmission thus constituted with induction coils having very resisting
long secondary wire, provided with their sets of internal iron wire has the remarkable
property of being able to act even when the general circuit is open at some point.
The intensity of the transmissions is naturally much weakened but it can always be
made sufficient for the exchange of communications by causing the vibrating trans-
mitting body to produce its maximum effect on the microphones.
Microphonic call. This maximum effect is obtained very simply by placing the
microphone without any intermediary upon the sound box of the electro-diapason.
For ordinary transmissions with closed circuit this effect is too intense for the mono-
telephones to sufficiently separate the simultaneous multiple transmissions; it is
necessary to reduce the intensity by for example separating the sound box from the

page_text: microphone by caoutchouc sheets. But the maximum effect can then be usefully
employed for a call preceding a series of transmissions because in the receiving mono-
telephone which is in unison with that which calls the call can be heard by listening
at about 1 metres from the receiver, and at 1 or 2 metres without paying special
attention whilst in the other monotelephones one only hears by placing the acoustic
tubes to the ears. The call can be rendered characteristic by producing a different
agreed signal for each transmitter, and its effect can also be increased by employing
the arrangement described under § 6 or by taking advantage of the amplitude of the
movements produced to ring a bell by any of the known means. Further, it is not
necessary to employ for producing the call a vibrating transmitting body which is far
from the operator who wishes to call. It suffices to place at the side of each manipu-
lator an auxiliary call microphone which can be momentarily substituted for the
transmitter by means of a commutator and to make it vibrate by placing upon the
diaphragm a vibrating body of small dimensions such as a reed horn (cornet à anche)
exactly tuned in unison with the corresponding transmitter. I can also in cases where
each transmitter has its induction coil placed at the side of each manipulator reduce
the maximum intensity of the microphones fixed without an intermediary to the sound
box by withdrawing the wires always placed inside the coils and afterwards inserting
these wires into the coil to produce, by manipulating, the maximum effect and the
call. The auxiliary call microphone would then be unnecessary. This kind of
musical microphonic call is applicable to all the preceding modes of transmitting. It
suffices to introduce into the circuit the secondary wire of the coil of the call
microphone.
APPLICATION OF THE PRECEDING MODES OF TRANSMISSION TO MULTIPLE OPTIC
TELEGRAPHY.
The modes of teleradiophonic (photic and thermomicrophonic) transmission pre-
viously described are applicable to optic telegraphy. For this purpose, it suffices at
the transmitting station to collect the rays which have traversed the holes of the
interrupting wheel, at the focus of a lens or of a mirror as is ordinarily done in optic
telegraphy. One thus reflects to the distant station with which one wishes to com-
municate, the pencil of rays rendered cylindrical and which is really composed of the
superposition without confusion of as many individual pencils as there are sets of
holes in the wheel each of these pencils vibrating according to the special mode
relative to the sounds of the scale. The direction of the pencil is determined before
hand as is usual and a telescope the optical axis of which is parallel to this direction
enables the rays emitted by the. corresponding station to be seen.
At the receiving
station the pencil of vibrating rays is received and concentrated at the focus of a
mirror or glass on one of the photophones or on the thermomicrophone herein before
described connected to the monotelephonic receivers and forming with them a closed
circuit.
It need hardly be said that mirrors or telescopes can be substituted for the lenses
and that the same effect can be obtained with the aid of reflection prisms or other
known optical systems arranged so that the optical emitting apparatus serves also for
receiving. All that relates to manipulation, to the synchronisin of the wheels, and to
the reception is identical with what has been already explained under headings I and
II of this specification.
11
T 1
1000

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Multiple Telegraphy.
I, ERNEST JULES PIERRE MERCADIER of 1 Boulevard St. Denis, Paris, France,
Electrical Engineer do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
This invention is based :-
1st. On the co-existence of the small electric undulations simultaneously occurring
in an aerial, underground or submarine conductor and their crossing each other with-
out confusion, a continuous current or a permanent electrostatic charge having been
previously established in the said conductor.
2nd. On the employment of radiophonic (photic or thermic) transmitters and
_microphonic transmitters of novel nature and arrangement.
3rd. On the employment of novel receivers which separate the electric vibrations of
. different rhythm.
Its object is to transmit simultaneously through the same line in the one or the
other direction several signals in accordance with a conventional alphabet.
It comprises two modes of transmission, the one teleradiophonic, the other tele-
microphonic and one mode of reception; these are hereinafter successively described.
[A] Photic teleradiophonic transmission, or telephotophone.
§ 1. TRANSMITTER.
In this case the transmitter is composed of four parts:-
1st. Optic.part. A pencil of parallel luminous rays from any sufficiently intense
source S (Figure 1) such as an oxyhydrogen lamp or an incandescent or are electric
lamp; the pencil passing through a cylindrical lens C produces a rectangular image of
about a centimetre wide and from six to eight centimetres long.
a disc of
2nd. Interrupter part. An interrupting wheel R (Figures 1 and 2) of constant
speed for producing intermittences in the luminous pencil according to the different
rhythms. For this purpose, if it is of metal, say zinc, copper, aluminium &c., it is
formed with several sets of holes of different number; if it is of glass
thick paper previously formed with several sets of holes is pasted over it. On a
wheel of 55 centimetres diameter there can be seven sets of circular holes of ten
millimetres diameter, the numbers of which are respectively the same as the numbers
of the vibrations of the sounds of a diatonic scale, for example: Dot, Ret, Mit, Fut,
Sol, Lab, Sit.

page_text: The result is that the part of the luminous pencil that passes through each set of
holes will be intercepted by the solid parts of the wheel turning at a speed of
about 11 revolutions per second, according to the rhythm special to each set. This
speed is sufficient to produce in the extreme set which has 95 holes, 1045 inter-
ruptions per second. Now Sit corresponds to about 974 vibrations per second.
By giving to the seven sets respectively the numbers of holes, 50, 56, 63, 67, 75, 84
and 95, the sounds of the diatonic scale are very nearly approximated.
For brevity I will call the sets of holes and the luminous rays which traverse them
by the names of the corresponding notes of the scale of the sign; thus set and
ray Re, set and ray Solt, &c.
3rd. Radiophone. An electric radiophone of rectangular form F (Figure 1)
sufficiently large to receive the seven rays Do Re, &c. It should have a very
great resistance and a sensitiveness sufficient for the radiations; it is formed of one
of the following bodies:-solenium alloy of selenium and tellurium, lamp black;
sulphide, iodide, bromide or chloride of silver; sulphide of tin; sulphide of antimony;
galena; oxide of copper or of iron, phosphide of zine, all but the three first named
bodies are new in the employment for or application to this purpose.
I will describe only the preparation of radiophones formed of selenium, sulphide of
silver, and sulphide of tin; the others will be made in a similar manner.
The seleniuin radiophone (Figure 3) is formed of two brass places LL' two centi-
metres wide and from six to ten centimetres long; they are juxtaposed but covered
with layers of asbestos paper A which press them against each other and at the same
time insulate them. They are connected together at their ends by two ebonite cross-
pieces E E¹. On the asbestos are wound in close spirals and parallel, two wires of
platinum, copper, brass or other metal marked f and f¹ in the figure (the wire fl
being shown in dots); the two ends of the wire f are fixed to the plate L and those
of the wire f to the plate L'.
Before fixing the ebonite cross pieces the apparatus is heated on a mica plate to a
temperature such that a crayon of selenium placed thereon will begin to melt (about
210 Centigrade); the crayon is then rubbed rapidly over the surface of the apparatus,
care being taken to well fill the spaces between the two wires f and fand to main-
tain the temperature; the apparatus is then left to cool so that the selenium surface
may preserve a dark-grey color.
By leaving a space of about a millimetre between the two wires a radiophone is
obtained which is very sensitive to intense light; its electrical resistance rises
gradually to about 300.000 ohms and afterwards remains constant for several years
without the apparatus losing its properties. This resistance can be reduced at will by
diminishing the space between the wires.
The sulphide of silver radiophone (Figure 4) is formed of wires such as silver,
platinum, aluminium, iron &c. wound in the same manner upon a layer of sulphide S
spread first on an insulating plate A of asbestos, cork or mica in the form of a convex
cylinder. The wires pass round two ebonite piates LL' which can be separated from
each other by two screws V V₁; this allows (and this is a very important point) of
varying as required the pressure of the wires on the layer of sulphide. These wires
terminate, as do those of the radiophone previously described, at two insulated binding
screws Band B'. The layer of sulphide of silver can be produced by taking a silver
plate, sprinkling it with flour of sulphur and heating gently underneath through a
mica plate, and then slowly evaporating the excess sulphur, or it can be produced by
electrolysis.
The appropriate resistance is obtained by varying the thickness of the layer of
sulphide, the pressure, and the space between the two wires.
Radiophones of iodide, bromide and chloride of silver melted can be made in the
same manner. It is the same with selenium which can be melted and spread upon an
insulating surface and afterwards wound with a double helix of wires.
It is also the same with sulphide of tin and generally with the hard bodies among
those hereinbefore named, with this difference, that these can be set in sealing wax
and filed at the surface.
:
:

page_text: 4th. Manipulator. Manipulators of a number equal to that of the sets of holes in
the revolving wheel, Figures 1 and 2 show them. A thin rod t of aluminium about
ten centimetres long carries a diaphragm or disc d about one centimetre square; it
can move upon a centre A under the action of an electro inagnet E on an armature
about one to two centimetres long on the end of the rod and which is capable of
moving a distance of two to three millimetres between the core of the electro-magnet
and a stop B, which, as well as a counterspring r is carried by a bracket adjoining
the electro magnet, The electro-magnet is incited from a distance by means of a
battery P and a suitable manipulator, a Morse manipulator for example.
Seven similar electro magnets and rods are fixed on the table which supports the
shaft of the revolving wheel in such manner that in the state of rest the diaphragms d
arrest the rays Dot, Ret, &c. In order that one of them Sol for example may
pass through the wheel and fall on the radiophone it is necessary to work that
one of the seven manipulators, such as M which corresponds to the electro-magnet
of the rod and diaphragın appertaining to the set Sol
For brevity each manipulator, as well as the electro magnets, rods, diaphragms,
sets of holes, and luminous rays which pass through them, can be called by the
denominations Do Re &c.
In the positions indicated by Figures 1 and 2 the diaphragms close the holes
situated in a plane passing through the ends of a horizontal diameter; this con-
stitutes for the electro-magnets and the diaphragm rods a simple arrangement which
is easily understood on reference to the figure.
The arrangement of the manipulators as above described is not indispensable, any
other means whereby the luminous rays are allowed to pass in accordance with a
given rhythm would answer.
The transmitter having been thus arranged let us suppose a circuit comprising a
battery, the radiophone and an ordinary telephone, the interrupting wheel turning
with a speed of about 11 revolutions per second, rendered constant by the means
hereinafter described. If the hand be pressed on manipulator Min for example, the
set of holes Mi will be uncovered and according to the laws of the radiophone a
continuous sound Mit will be heard in the telephone. Should the manipulator
produce Morse signals for example these signals will be perceptible to the ear at the
telephone just as experienced telegraphists understand Morse signals by simply
listening to the rhythmic sound produced by the pallet of the electro magnet of the
apparatus against the stops; or rather, just as the same telegraphists perceive with the
eye the signals of optic telegraphy, the manipulation being the same in both cases.
If instead of only one manipulator the seven manipulators are operated, the ear will
hear in the telephone simultaneously the seven kinds of signals which are simply
superposed, each of them preserving its individuality, and without their affecting each
other. Further on is described how by means of special receivers this superposition
can be avoided and each kind of signals can be distinctly isolated from the others.
Speed Regulator. But the putting of the transmitter into action supposes as I have
above stated that the speed of the interrupting wheel is constant. I will now describe
how this constancy is produced, established and maintained (see Figure 2).
The interrupting wheel R on which only the set of holes S of Sit is shown is put
in motion by means of a cord passed over a pulley P on its shaft and over another
pulley fixed on the shaft of a small electric motor N. This motor is actuated by a
battery K as constant as possible, for example a Clamond thermo electric battery
heated by means of a constant current of gas; an ampère meter A' and a rheostat h
are introduced into the circuit of the battery and motor wire. The desired speed of
the wheel is thereby produced. Any other motor having a sufficiently precise
regulation of speed can be employed.
This speed is established by an acoustic process. For this purpose a caoutchouc
tube t' of a length calculated to raise the sound Sit has one of its ends placed some
millimetres from the projection formed by the holes of the set Sit; the impact of
the air drawn through each hole over the edges of the tube produces the sound Si by
mechanism analogous to that of the acoustic instrument known as the Sirene. The

page_text: other end of the tube is placed inside the sound box G of an electro diapason Sin the
movement of which is maintained electrically by means of one or two Daniell
elements p. The result is that when the speed of the wheel progressively increases
the sound produced by the tube t' rises; when it approaches Sit there are heard the
beats produced by the sound of the tube and that of the electro diapason. When
the beats cease the two sounds are identical and the speed of the wheel is appropriate;
the absence of beat establishes this. A sound can be produced with the projections
of the holes in the wheel otherwise than by a tube; it suffices for example to rub
a piece of paper over these holes. In short it is sufficient to produce in any
manner a sound characteristic of the speed of the wheel.
In order to maintain this speed it is sufficient to maintain this absence of beat, or
rather to constantly maintain one or two beats per second. This object is attained by
means of the rheostat h which allows of varying the battery current and consequently
the speed of the motor and of the wheel. The sensitiveness of this regulation.is obvious;
the number of beats per second being equal to the difference between the numbers
of the vibrations of the sounds of the tube and of the electro diapason and this latter
making about 974 complete vibrations per second, by maintaining this difference at
nearly one beat per second which every one can estimate the speed of the wheel is
certain to be maintained constant at nearly 14.
For brevity I will give the name of acoustic tachymeter to this combination of the
tube t¹ or any other device which allows of producing a sound characteristic of the
speed of a wheel and of the electro-diapason furnished with its sound box, the whole
intended to establish and to estimate at about 1000 the variations of speed of a
revolving wheel above or below a given speed and this without sensibly affecting this
10
Multiple effect monotelephone.-The receiver is a monotelephone or an electro-
magnetic sounder. It is a telephone the diaphragm of which, circular or rectangular,
is not held at the edges; if it is circular it is placed upon three points forming
the apices of an equilateral triangle drawn in the circumference constituting the
nodal line of the first harmonic; if it is rectangular it is placed on the two nodal
lines of the fundamental sound at 22 of the length reckoning from the ends.
If a set of undulatory currents of different rhythms be passed into the coil of the
apparatus which has a resistance of 300 or 400 ohms a diaphragm vibrates in an
appreciable manner only under the action of the currents the vibratory period of
which is equal to that of the first harmonic of the diaphragm, if it is circular,
and to that of the fundamental sound if it is rectangular. This is the characteristic
property of the apparatus.
In the circular monotelephone which is represented in section in Figure 5; the
diaphragm D is placed on three points p movable along graduated slides fixed to a
platform P. A cover C has a central, socket to which is fitted a caoutchouc tube T
provided with a mouthpiece e for receiving the sounds from the stratum of air above
the diaphragın. A second similar tube T fitted to a metal tube t which terminates
above the platform as close as possible to the pole of the electro-magnet E, collects
the vibrations of air below the diaphragm; the result is that by applying to the ears
the mouthpieces of the tubes T and T which can be kept there by means of leathern
straps fitted to the head of the person who listens, he will hear two identical sounds
when the diaphragm vibrates, in such manner that the apparatus is thus of double
effect and that the listener is screened from external noises and has both hands
free.
Regulation. The apparatus is further provided with means for regulating it. A
small brass cylinder or weight I can slide along a radius of the diaphragm ; for this
purpose it is held on one side by means of a thin strip of caoutchouc b and on the other
side by a thread wound over a drum B; by turning this the cylinder approaches
more or less to the centre of the diaphragm and its weight causes more or less

page_text: The telegraphic system to be complete requires that each station shall be able to
transmit or receive at will and that each operator shall be able to speak at any
moment to his correspondent for rectifications or collations. It is therefore necessary
to have as indicated in the diagram, Figure 6:-
[a] At the transmitting station: a battery P communicating on the one hand with
earth and on the other with one of the poles of the radiophone F; in front of this
the interrupting wheel provided with its optic system, its motor, its tachymeter and
its seven manipulators, seven monotelephones m' tuned to the sounds of the diatonic
scale of Do and introduced in the circuit beyond the radiophone. Seven operators
are placed in a room other than that which contains the radiophone, the wheel and its
accessories; each of them is provided with means for holding to his ears the mouth-
pieces of the tubes of a monotelephone, and he has under his hand the corresponding
manipulator, that is to say, that which produces the sound for which the monotelephone
is tuned; he therefore hears his own transmission and is always ready to receive that of
his correspondent who manipulates the same sound. The telegraphic line L is con-
nected to the last monotelephone.
[6] At the receiving station: an absolutely identical arrangement comprising seven
monotelephones m², a radioplione F2 with final communication to earth, an inter-
rupting wheel driven at the same speed and having its optic system, motor, tachymeter,
and manipulators. The identity of the monotelephones at the two stations is assured
by their construction but the means of regulating above described allows of any
constructive defect being remedied, and of ensuring maximum intensity to the
sonorous signals received. The identity of the speed of the two wheels is insured by
that of the electro diapasons of the tachymeters, but the very slight difference which
can arise from the temperature could also be easily corrected by means of the
regulators of the monotelephones. But in order to have more certainty in the
synchronisin of the wheels it is sufficient to fit the electro diapasons with a very
light aluminium cursor. At the commencement of a communication an operator at the
transmitting station regulates the movement of his wheel so that there may be no beat
between the two soundsin of the tachymeter; an operator at the receiving station hears
the sound received in the inonotelephone Sit; if it beats with the sound of the electro
diapason he will move the cursor of this until the beat ceases; the synchronism of
the wheels of the two stations will thus be ensured.

page_text: without the central station having to give them communication by means of com-
mutators or other similar appliances. It is sufficient for this-1st, That each station
should possess a wheel with twelve sets of openings, twelve manipulators and the
twelve corresponding monotelephones; 2nd That notice should be given of the station,
which calls. This notice would be given by the central station. The station called
could then serve to receive the messages from the monotelephone in unison with that
of the temporary correspondent and of the corresponding manipulator for transmitting
them.
The intensity of the effects produced in the monotelephone can be increased by
transforming its diaphragm into a microphone; for this purpose it suffices to fix at a
point of the circumference a carbon rod of one and a half millimetres diameter and
ten inillimetres long by means of a small loop of aluminium foil and to place in a
notch made in the rod another rod of three millimetres diameter and 30 to 40 milli-
metres long engaged at its other end in a hole formed in a small carbon block fixed
on the platform of the apparatus. One has only to connect the block on the one hand
and the diaphragm on the other with a battery and the primary wire of the induction
coil of an ordinary microphone; the secondary wire being connected to a telephone
this reproduces the reinforced sounds of the diaphragm.
[B] THERMIC TELERADIOPHONIC TRANSMISSION OR TELETHERMO MICROPHONE.
The transmitter above described includes a radiophone particularly sensitive to
luminous radiations; it is a photic radiophone or photophone.
A radiophone can be employed principally sensitive to thermic radiations, that is to
say a thermic radiophone or thermophone, but it is necessary for it to produce electric
undulations in the circuit which it has to work. For this purpose the apparatus is
composed (see Figure 7) of an ordinary microphone of eight to ten centimetres
diameter, the diaphragm D of which, of wood or metal, supports sufficiently light
carbons about three millimetres in diameter and five or six centimetres long; their
ends are connected as usual to the poles of a microphonic battery p through the inter-
mediation of the primary wire f of an induction coil B, the resistance of which is only
a few ohms; the secondary wire F is very fine; it is composed of a very great
number of turns and therefore offers a great resistance; it is connected to a line
battery P (the other pole of which goes to earth) and to the telegraph line L.
The surface of the diaphragm is coated with lamp black and covered with a thin
glass plate V, forming therewith an enclosed air chamber of only five or six milli-
metres deep. The glass plate is exposed to the intermittent radiations which pass
through it and produce variations of temperature in the layer of air in contact
with the lamp black; there is consequently a vibratory movement in the body of air
in the chamber which is transmitted to the diaphragm D of the microphone; this
therefore acts as usual, and produces in the current which passes through the wire F
and the line L electric undulations of the same rhythm as that of the air chamber.
The apparatus is fixed to a support S by means of an elbow joint G which allows of
the maximum sensitiveness being given to the microphonic system. I will call this
apparatus for brevity the Thermomicrophone.
If the telegraphic line has not a great resistance an induction coil B suffices, and
even this can be dispensed with, the microphone being then connected to the line and
to the battery P. If this line and the apparatus which are interposed offer great
resistance the microphone is connected to a set or battery of coils the primary wires
and secondary wires of which can be connected in series or for quantity according to
circumstances, as is ordinarily done with the elements of a battery or pile.

page_text: In the preceding apparatus a thin glass plate can be employed for the diaphragm D,
the air chamber can be made with glass sides and instead of the air therein gases or
vapors can be used which energetically absorb the luminous radiations, such as the
vapors of iodine, hyponitric acid &c., the effect of which would be added to the thermic
effect of the lamp black.
Lastly I can construct, as I have described for the photophone, thermophones with
lamp black, iodide of silver or other substances particularly sensitive to thermic
variations; they then act without a microphonic intermediary.
In the case of a thermomicrophonic radiophone transmitter the poles of the radio-
phones F and F Figure 6 are replaced by those a. b Figure 7 of the induction coil or
of the battery of induction coils, the one a being connected to the monotelephones m'
and m², and the other b to the battery P and earth.
The mode of telethermophonic transmission above described can be, simplified or
rather transformed in the following manner: I suppress all radiophonic action well
as the interrupting wheel.
as
Transmitter I take electro diapasons tuned exactly to the sounds of the chromatic
scale and provided with a sound box such as G, Figure 2. On each of these boxes G
I fix the apparatus above described as the thermomicrophone, or even an ordinary
microphone, M Figure 8; or simpler still, I fix the carbons of an ordinary microphone
on the upper surface of the sound box which thus serves as a diaphragm directly acted
upon by the vibrations of the diapason. The primary wires 1, 1 of the induction coils
of the twelve microphones, instead of each forming a special circuit including its
battery, can be connected together either in series or for quantity in the circuit of a
suitable battery. The secondary wires 2, 2 can be connected together in a manner
analogous to that in which the elements of a battery are connected and terminate at
the telegraph line on the one side and at earth on the other. at the transmitting
station. I can employ coils twenty centimetres long and three centimetres in diameter
for the secondary wires, and they can easily be given a resistance of 5, co to 6,000
ohms, and if necessary I can use a battery of coils of this kind, according to the special
conditions of the line to be worked. As regards manipulation this is effected by
means of a Morse manipulator N for example introduced into the primary wire of cach
microphone. The transmitter clement thus constituted can be called a microphonic
electro-diapason. But it is evident that I could employ for causing the microphones
to vibrate any other body which vibrates in a permanent and regular manner, such as
a sonorous pipe for example.
Receiver The receivers are the monotelephones already described. There is
nothing to change in the mode of reception.
Arrangement of the Stations-One of the ends of the secondary wire of the induction
coil or battery of induction coils goes to earth at the transmitting station; the other
end is connected to the line after having passed through the monotelephones m¹
Figure 8. At the receiving station the arrangement is the same.
All these parts,
secondary wires of the coils and monotelephones, are introduced into the circuit the
two ends of which go to earth. Figure shows au arrangement of a transmitting
station with two transmissions; it will be the same whatever be the number of the
transmitters. This arrangement is suited for multiple telegraphic correspondence
between two stations. As to the exchange of communications between a central
station and several others, the remarks herein before made under § 5 will apply. I
will add that I can introduce a battery such as P, Figure 6, into the general circuit.
The mode of transmission thus constituted with induction coils having very resisting
long secondary wire, provided with their sets of internal iron wire has the remarkable
property of being able to act even when the general circuit is open at some point.
The intensity of the transmissions is naturally much weakened, but it can always bos

page_text: made sufficient for the exchange of communications by causing the vibrating trans-
mitting body to produce its maximum effect on the microphones.
Microphonic Call-This maximum effect is obtained very simply by placing the
microphone without any intermediary upon the sound box of the electro-diapason.
For ordinary transmissions with closed circuit this effect is too intense for the mono-
telephones to sufficiently separate the simultaneous multiple transmissions; it is
necessary to reduce the intensity by, for example, separating the sound box from the
microphone by caoutchouc sheets." But the maximum effect can then be usefully
employed for a call preceding a series of transmissions, because in the receiving
monotelephone which is in unison with that which calls, the call can be heard by
listening at about ten metres from the receiver, and at one or two metres without
paying special attention whilst in the other monotelephones one only hears by placing
the acoustic tubes to the ears. The call can be rendered characteristic by producing
a different agreed signal for each transmitter, and its effect can also be increased by
employing the arrangement described under § 6, or by taking advantage of the
amplitude of the movements produced to ring a bell by any of the known means.
Further it is not necessary to employ for producing the call a vibrating transmitting
body which is far from the operator who wishes to call. It suffices to place at the
side of each manipulator an auxiliary call microphone which can be momentarily
substituted for the transmitter by means of a commutator and to make it vibrate by
placing upon the diaphragm a vibrating body of small dimensions, such as a reed
horn (cornet à anche) exactly tuned in unison with the corresponding transmitter. I
can also, in cases where each transmitter has its induction coil placed at the side of
each manipulator, as shown in Figure, reduce the maximum intensity of the micro-
phones fixed without an intermediary to the sound box by withdrawing the wires
always placed inside the coils and afterwards inserting these wires into the coil to
produce, by manipulating, the maximum effect and the call. The auxiliary call micro-
phone would then be unnecessary. This kind of musical microphonic call is applicable
to all the preceding modes of transmitting. It suffices to introduce into the circuit
the secondary wire of the coil of the call microphone.
;
APPLICATION OF THE PRECEDING MODES OF TRANSMISSION TO MULTIPLE
OPTIC TELEGRAPHY.
The modes of teleradiophonic (photic and thermomicrophonic) transmission pre-
viously described are applicable to optic telegraphy (see Figure 9). For this purpose
it suffices at the transmitting station to collect the rays which, coming from a source S,
have traversed the holes of the interrupting wheel R at the focus of a lens or of a
mirror, as is ordinarily done in optic telegraphy. One thus reflects to the distant
station with which one wishes to communicate, the pencil of rays rendered cylindrical
and which is really composed of the superposition without confusion of as many
individual pencils as there are sets of holes in the wheel R, each of these pencils
vibrating according to the special mode relative to the sounds of the scale. The
direction of the pencil is determined beforehand as is usual, and a telescope the optical
axis of which is parallel to this direction enables the rays emitted by the corresponding
station to be seen. At the receiving station the pencil of vibrating rays is received
and concentrated at the focus of a mirror or glass on one of the photophones or on the
thermomicrophone herein before described (Figures 3, 4 and 7) connected to the mono-
telephonic receivers also described (Figure 5) and forming with them a closed circuit.
Figure 9 shows a transmitting and receiving arrangement in which the letters S, C, R,
indicate respectively the same parts as in Figure 1, and represent the source of light, the
optical system, and the interrupting wheel. 1 is the rectangular image of the source S

page_text: It need hardly be said that mirrors or telescopes can be substituted for the lenses
and that the same effect can be obtained with the aid of reflection prismns or other
known optical systems arranged so that the optical emitting apparatus serves also for
receiving. All that relates to manipulation, to the synchronisin of the wheels, and to
the reception is identical with what has been already explained under headings I and
11 of this Specification.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is
1. The system of multiple telegraphy arranged and working substantially as herein-
before described.
2. The combination substantially as set forth, of the radiophonic transmitters here-
inbefore described with the receivers.hereinbefore described and called multiple effect
monotelephones, whereby twelve dispatches can be transmitted simultaneously through
a single wire and be distinguished at the receiving station by the sounds comprised in
a chromatic scale Do, Do, Re, Ret, Mi, Fa, Fa, Sol, Sol, La, La, Si, according to
a conventional alphabet such as the Morse for example, as explained.
3. The system of multiple telemicrophony arranged and working substantially as
herein before described.
4. The employment or adaptation of the system of multiple telegraphy hereinbefore
described to the exchange of dispatches or communications between a central station
and twelve others arranged in derivation, in the line, or otherwise, the said twelve
stations being also able to communicate with each other, all substantially as set forth.
5. The adaptation or application of photic and thermomicrophonic teleradiophony to
multiple optic telegraphy substantially as hereinbefore described.
6. In the transmitters, the employment as photophonic substances, of sulphides of
silver, lead, tin, and antimony; chloride, bromide and iodide of silver; oxides of
copper and iron; and phosphide of zinc, as described.
7. In the transmitters in which the substances enumerated in claim 6 or substances
previously used in transmitters, such as selenium, lamp black, and alloy of selenium
and tellurium are employed, a novel construction or arrangement comprising a double
helix of wire the pressure of which on the substance employed can be varied so that a
determined and constant resistance can be given to the radiophone, whereby it becomes
practicable to produce sufficiently intense radiophonic sounds with a current of
0.00002 of an ampère at the maximum, and much less with electric light, as set
forth.
8. The means, substantially as herein before described, whereby a constancy, within
nearly one thousandth of the speed of an interrupting wheel is produced, established
and maintained, the said means comprising the acoustic tachymeter described and a
motor capable of regulation.
9. The means, substantially as hereinbefore described, of obtaining synchronism of.
the two interrupting wheels at the two ends of a line, the said means comprising two
identical tachymeters at the two ends of the line respectively.
10. The employment, in the transmitters, of thermophonic substances, such as iodide
of silver and lamp black and of photophonic substances such as vapours of iodine and
of hyponitric acid to produce a thermic radiophone or thermophone as set forth.
11. The thermomicrophonic transmitters herein before described.
12. Microphonic transmitters made to vibrate by a body which vibrates in a per-
manent and regular manner, such as an electro diapason, or a sonorous pipe, com-
bined or not with sets or batteries of induction coils having very long and resisting
secondary wires, and capable of working either with an open or closed circuit with or
without a battery in the circuit of the secondary wire, substantially as hereinbefore
described.
13. The musical microphonic call herein before described.
14. In the receivers, the monotelephone constructed substantially as hereinbefore
described which separates the sounds received.

page_text: 15. The arrangement substantially as described whereby a double effect can be
obtained at the receiving station.
16. The means comprising a weight which can he moved along a radius of the
diaphragm of the receiving instrument whereby the height of the sound can be varied
substantially as hereinbefore described.
17. The transformation or conversion of the diaphragm of the monotelephone into
a microphone as hereinbefore described and its transformation or conversion into a
bell relay as described.
18. The monotelephone with rectangular diaphragm substantially as hereinbefore
described.