IMPROVED MEANS OR METHOD OF TRANSMITTING OR CAUSING SOUND BY MEANS OF AN ELECTRIC CURRENT OR CURRENTS FOR THE PURPOSE OF CONVEYING MESSAGES AND OTHER USEFUL PURPOSES
Year: 1879

page_text: LETTERS PATENT to Louis John Crossley, of Halifax, in the County of York,
Carpet Manufacturer, for the Invention of "IMPROVED MEANS OR METHOD OF
TRANSMITTING OR CAUSING SOUND BY MEANS OF AN ELECTRIC CURRENT OR
CURRENTS FOR THE PURPOSE OF CONVEYING MESSAGES AND OTHER USEFUL
PURPOSES."
Sealed the 25th April 1879, and dated the 1st February 1879.
PROVISIONAL SPECIFICATION left by the said Louis John Crossley at the
Office of the Commissioners of Patents on the 1st February 1879.
LOUIS JOHN CROSSLEY, of Halifax, in the County of York, Carpet Manufacturer.
"IMPROVED MEANS OR METHOD OF TRANSMITTING OR CAUSING SOUND BY MEANS
OF AN ELECTRIC CURRENT OR CURRENTS FOR THE PURPOSE OF CONVEYING
MESSAGES AND OTHER USEFUL PURPOSES."
My Invention has for its object improvements in transmitting or causing sound
by means of an electric current or currents, and by an instrument known as the
microphone used in conjunction, with a telephone, for the purpose of conveying
articulated messages, speech, or other sounds and for other useful purposes, by
which means an increase of intensity of sound is produced, conveying faithful, plain,
and distinct messages.
For this purpose I employ an ordinary microphone, which I fit or mount upon a
parchment diaphragm which is stretched or fixed over the top of a drum, box, or
other suitable kind of resonant; but diaphragms of any other kind of suitable
substances may be employed.
The microphone when mounted or fitted on the parchment diaphragm is con-
nected with a battery and induction coil in such a manner that any variations in
the microphone caused by sound waves or by any other means effects a corre-
sponding reaction in the strength of the current of electricity flowing through the
microphone and induction coil; the variation also causes a variation in the current
induced in the induction coil, which being connected to a telegraph line or to any
other electrical wires causes corresponding currents to flow through the telegraph
or electrical wires, and by attaching a telephone to the distant end of the telegraph
or electrical wires causes by the increase of the intensity of the sound produced, the
messages conveyed to be faithfully, plainly, and distinctly heard and recorded.

page_text: the said Louis John Crossley in the Great Seal Patent Office on the 20th
-June-1879.-
LOUIS JOHN-CROSSLEY,-of-Halifax,_in_the_County_of York, Carpet Manufacturer.
"IMPROVED MEANS OR METHOD OF TRANSMITTING OR CAUSING SOUND BY MEANS
OF AN ELECTRIC CURRENT OR CURRENTS FOR THE PURPOSE OF CONVEYING
MESSAGES AND OTHER USEFUL PURPOSES."
The said Invention has for its object improvements in transmitting or causing
sound by means of an electric current or currents, and by employing a compound
microphone used in conjunction with a telephone, for the purpose of conveying
articulated messages, speech, or other sounds and for other useful purposes, by
which means an increase of intensity of sound is produced, conveying faithful,
plain, and distinct messages.
For this purpose I einploy a compound microphone, that is to say, microphones
having three, four, or more pencils, and six, eight, or more surfaces touching each
other, by which means the resistance of the circuit is varied, and whether arranged
with pencils or of any other form; the compound microphone is mounted or fitted
by preference on a wood diaphragm, and I find pine wood to answer well, but the
microphone may be mounted or fitted on a parchment diaphragm which is
stretched or fixed over the top of a drum, box, or other suitable kind of resonant,
and diaphragms of any suitable kind of substance may be employed. The
compound microphone when mounted or fitted on a diaphragm is connected with a
battery and induction coil in such a manner that any variations in the compound
microphone caused by sound waves or by any other means, effects a corresponding
reaction in the strength of the current of electricity flowing through the compound
microphone and induction coil; the variation also causes a variation in the current
induced in the induction coil connected to a telegraph line or to any other electrical
wires, which cause corresponding currents to flow through the telegraph or electrical
wires, and by attaching a telephone to the distant end of the telegraph or electrical
wires, cause, by the increase of the intensity of the sound produced, the messages
conveyed to be faithfully, plainly, and distinctly heard and recorded.
But in order to enable my improvements to be better understood I will proceed
to describe the same by reference to the accompanying Drawing, in which Figure 1
represents a plan of a compound microphone having four pencils, eight surfaces,
and four carbon blocks, the microphone being mounted on a wood diaphragm ;
Figure 2, sectional elevation of the same; Figure 3 represents a plan of a compound
microphone with four carbon blocks fitted with four strips of thin copper instead
of the carbon pencils; Figure 4, sectional-elevation of the same; Figure 5 repre-
sents a microphone and telephone connected in circuit with a battery and induction
coil Figure 6 represents the joining up between two stations with compound
microphones and telephones connected in circuit with batteries and induction coils.
Similar letters of reference are used to represent similar parts. Figures 1 and 2
in the accompanying Drawings represent a compound microphone in which four
pencils of carbon A, B, D, E, are held loosely in four carbon blocks F, G, H, I; the
microphone is mounted by preference upon a piece of wood or diaphragm J, and I
find pine wood under certain circumstances to answer well and produce better
articulation than other kinds of wood when used for this purpose; the microplionè
is enclosed by a wooden rim K, and a cover L may be fitted over the top of the
rim and made by preference of thin wood, or the microphone may be left open.
I may construct the compound microphone without carbon pencils, which may
be replaced by other suitable substances capable of varying the resistance of an

page_text: electric circuit in a similar manner to the pencils and carbon blocks, Figures 3
and 4; in the carbon blocks F, G, H, I, I fit thin metal strips M, by preference of
copper or other light substance; the strips are mounted on four pillars O, and to
each end of the strips I fix a small piece of carbon P, or other substance capable of
varying the resistance of the circuit in a similar manner to the pencil points herein-
before described. I may fit or mount the compound microphone on a parchment
diaphragm which is stretched or fixed over the top of a drum, box, or other suitable
kind of resonant and diaphragms or any other suitable substauce may be employed.
I may also construct compound microphones joined up in a line, and also constructed
with more than four pencils and blocks.
The compound microphones having a greater number of vibrating points and
consequently a greater number of points in which the resistance of the circuit is
varied produce louder and more distinct articulated sounds, and are not liable to
get out of adjustinent like the microphones heretofore employed in which the
articulation is frequently imperfect; Figure 5 represents a compound microphone
and telephone connected in circuit with a battery and induction coil; one of the
carbon blocks H is connected with a battery Z, C, and another block F is connected
with the primary wire P of an induction coil Q, the other end being connected by
a wire R to the battery Z, C; one side of the secondary wire is connected by
electrical wires S to a distant telephone T, and the other end of the secondary
wire U to earth V or to a return wire. The compound microphone and induction
coil can be joined up in many varied ways, which joining is well known to
electricians, and the induction coil need not be of the simple form shewn, but
may be varied, and two, three, or more induction coils may be joined up in
circuit, or the induction coil or coils may be used in connection with a
condenser, and the compound microphone may be worked without the induction
coil and simply with a battery or magnetic machine or a thermo electric generator,
but I prefer the induction coil which produces better results; Figure 6 represents
the joining up between two stations of compound microphones and telephones con-
nected in circuit with batteries and induction coils, and for simplicity the switches
for bringing the alarm and other parts into circuit are not shewn, the plan shews
the instruments joined up between two stations W and X; one of the carbon
blocks H of each station is connected with a battery Z, C, and the blocks F are
connected with the primary wires P of the induction coils Q, the other ends are
connected by wires R to the batteries Z, C, and the sides of the secondary wires
are connected by electrical wires S to a telephone T, and the other ends of the
secondary wires U to earth V or to return wires, the telephones T are connected
by means of the line Y.
Having thus described my improvements, and the best means I am acquainted
with for carrying the same into effect, I would have it understood that I do not
confine myself to the precise details shewn and described, as they may be varied
without departing from the peculiar character of the Invention, and that I am
aware that ordinary microphones, that is to say, microphones having only one pencil
and only two surfaces touching each other, used in conjunction with a telephone
and induction coil, have been employed, and to these I lay no claim; but what I do
claim is,-
Firstly. The construction and employment of compound microphones, that is to
say, microphones having three, four, or more carbon pencils, or six, eight, or more
surfaces touching each other, by which the resistance of the circuit is varied; also
compound microphones constructed with thin metal plates instead of carbon pencils
and whether mounted upon parchment, wood, or any other suitable substance,
substantially as and for the purpose herein before described and represented in the
accompanying Drawing.
Secondly. The arrangement, construction, and employment of compound micro-
phones and telephones connected in circuit with a battery and induction coil, or
without induction coil, and whether worked by electricity from a battery, or a

page_text: magnetic machine, or by a thermo electric generator, substantially as hereinbefore
described, and represented in the accompanying Drawing.
In witness whereof, I, the said Louis John Crossley, have hereto set my
hand and seal, this Seventeenth day of June, in the year of our Lord One
-thousand-eight hundred and seventy nine.