IMPROVEMENTS IN TELEPHONIC APPARATUS
Year: 1883

page_text: LETTERS PATENT to Alfred Julius Boult of 323 High Holborn in the County
of Middlesex Engineer. for an Invention of "IMPROVEMENTS IN TELEPHONIC
APPARATUS a communication from Charles. S. Steelo of Washington DC
United States of America.
"
PROVISIONAL SPECIFICATION left by the said Alfred Julius Boult at the
Office of the Commissioners of Patents on the 2nd July 1883.
"
ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex
Engineer "IMPROVEMENTS IN TELEPHONIC APPARATUS [a communication from
Charles. S. Steelo of Washington DC United States of America.
In all previous telephone receivers the plate of iron or steel or of any material
capable of being acted on by magnetism or a plate of wood, ebonite, brass, or of
any equivalent material possessing resiliency has been used, secured firmly around
its edge in front of a pole of a magnet or of an electro magnet. When the plate
is secured around its edge, the straining of the plate when it is caused to vibrate
at its centre produces buzzing noises and acute snappings, which impair the
articulation, but when a plate is secured at one point only of its edge, and is
resting at one or more points of its edge on a support it is free to vibrate
tympanically at its centro, and is free from any strain which produces buzzing
or snapping sounds.
In this invention I use a plate of iron or steel or other material capable of being
acted upon by magnetism; or a plate of wood, brass, ebonite or of any equivalent
material of a resilient nature, having secured firmly to its centre a small piece of
iron about the size of the end of the magnet; the plate is firmly secured at one
point of its edge to a fixed support; extending over the head of the magnet, so
that the centre of the plate may be over the head of the magnet. The plate is
tilted up so as to make an acute angle with the axis of the magnet and its
edge rests on one or more points, where it is held by its own resiliency, whereby
tongue vibration is prevented, and tympanic action only can take place when it is
acted on by the variations of the magnetic force; or the plate may lie over the
F75... All

page_text: head of the magnet at right angles with the axis of the magnet, secured firmly at
one point only of its edge and resting at one or more points of its edge on a support
where it is held by its own resiliency.
Any form of permanent magnet or of electro magnet may be used having a coil
on its end nearest to the plate.
Another part of this invention relates to an apparatus for causing undulations in
a current of electricity in a telephonic circuit.
By this apparatus great changes in surface contacts between the loose and fixed
parts of the microphone or tension regulator are effected, and thereby great
variations in the tension of the current are produced.
The principle adopted by my correspondent in the shape-of-the-pencil-is-that-of-
the screw.
When air waves fall upon pencils or bars thus constructed, they will
rotate easily, and thereby greatly change their points of contact.
The pencils may be made entirely of carbon or of any other substance capable of
conducting a current of electricity, or they may be made of any suitable inaterial
on the ends of which are fixed short extensions of carbon or other material capable
of conducting an electric current; the two ends of each pencil to be connected
together electrically; the ends of the pencils in all cases to rest loosely in cavities
in blocks of carbon or other substance capable of conducting a current of electricity,
the said blocks to be insulated from each other.
In all cases the pencil must have either a spiral groove cut in it, or have secured
to it a spiral flange or several blades similar to those used on steam ship propellors,
or one or more paddle wheels or a narrow thin strip of any suitable material
twisted so as to form a spiral may be used..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Julius Boult in the Patent Office on the 2nd January
1881.
ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Engineer. "IMPROVEMENTS IN TELEPHONIC APPARATUS" a communication from
Charles S. Steele of Washington D. C. United States of America.
In all previous telephone receivers, the plate of iron or steel or of any material
capable of being acted on by magnetism or a plate of wood, ebonite or brass or of
any equivalent material possessing resiliency has been used, secured firmly all round
its edges in front of a pole of a magnet or of an electro magnet.
When the plate
is secured all round its edge, the straining of the plate when it is caused to vibrate
at its centre produces buzzing noises and acute snappings which impair the
articulation, but when a plate is secured at one point only of its edge and is
resting at one or more points of its edge on one or more supports, it is free to
vibrate tympanically at its centre, and is free from any strain which produces
buzzing or snapping sounds.
In this invention I use a plate of iron or steel or other material capable of
being acted upon by magnetism or a plate of wood, brass, ebonite or of any
equivalent material of a resilient nature, having secured firmly to its centre a small
piece of iron, the plate is firmly secured at one point of its edge to a fixed support
extending over the head of the magnet, so that the centre of the plate may lie over
the head of the magnet. The plate is tilted up, so as to make an angle with the
axis of the magnet, and its edge rests on one or more points where it is held by its
own resiliency whereby tongue vibration is prevented and tympanic action only
can take place when it is acted on by the variations of the magnetic force; or the
plate may lie over the head of the magnet at right angles with the axis of the
magnet, secured firmly at one point only of its edge and resting at one or more
points of its edge on a support where it is held by its own resiliency and touching
at no other part.
Any form of permanent magnet or electro magnet may be used having a coil on
its end nearest to the plate.
Another part of this invention relates to apparatus for causing undulations in a
current of electricity in a telephonic circuit.
This apparatus is an improved form of Hughes' microphone whereby great
changes in surface contacts between the loose and fixed parts of the microphone or
tension-regulator are effected and thereby great variations in the tension of tho
current are produced.
The principle adopted by my correspondent in the shape of the loose pencil or
bar of the microphone, is that of the screw or paddle wheel. When air waves fall
upon pencils or bars thus constructed they will rotate easily and thereby greatly
change their points of contacts.
The pencils or bars may be made entirely of carbon or of any suitable material
capable of conducting a current of electricity or they may be made of wood ebonite
or other suitable material on the ends of which are fixed short extensions of carbon
or other material capable of conducting an electric current, the two ends of ench
pencil being connected electrically, the ends of the pencils in all cases to rest loosely
in cavities in blocks of carbon, or other suitable material capable of conducting a
current of clectricity, the said blocks to be insulated from each other.
In all cases the pencil or bar must have either a spiral groove cut in it or have
secured to it a spiral flange or several blades similar to those used on Steam Ship

page_text: propellers, or one or more paddle wheels, or a narrow thin strip of any suitable
material twisted so as to form a spiral may be used in place of a pencil or bar.
In the accompanying drawings in which like letters of reference represent like
parts Fig 1 is a sectional elevation of the instrument with the plate at an angle to
the axis of the coil secured at one point only of its periphery; Fig 1ª is like Fig 1,
but the plate is fastened at two points; Fig 2 is like figure 1 but the plate is at
right angles to the axis of the coil; Figure 2* is like figure 2 but the plate is
fastened at two points; Figure 3 shews a method of applying the plate to a horse
shoe magnet Figure 4 is a plan of the triangular plate; Figure 5 shows the
microphone in plan with the paddle wheel in position; Figure 5 is a cross section
of the same on line YZ; Figure 6 shews one screw form of pencil; Figure 7 shews
elevation of another-form-of-microphone in which the pencil is dispensed with
and flut contact surfaces are employed; Figure 7 is a plan of the sane.
an
Referring to Figure 1, A is the inagnet and B the bobbin or coil; C is the plate
secured firmly at one point of its periphery to the case-D so that the point of the
periphery at C. is pressed firmly upon the fixed support or point D', and touching
the case at no other part, (which may be a portion of the case or a bit of wood or
the like secured to it) its resilience retaining it in that position. A¹ is the end of
the magnet and the plate Clies just clear of it and makes an nuute angle with the
axis of the coil as is clearly shewn at A C.
Figure 1 is the same as Figure 1, but the plate C is secured at the two points E
and of the case D instead of only at E as in figure 1, and touching the case at
⚫ on other part.
Figure 2 is also like Figure 1 except that the plate C forms right angles with
the axis of the coil at CA; Figure 2ª is like Figure 2, but the plate C is secured at
the two points E and C¹ instead of at one only as in figure 2.
In figure 3 a horse shoe magnet is employed and the plate is secured to one end
of it at the point E, passes over the other limb, and rests upon, or is secured to, the
fixed support or point D' of the case as before.
The form of the plate C may be varied and may be round, oval, oblong, square,
triangular or other convenient shape. The triangular form is shewn in figure 4 the
plate being fixed at E and resting upon supports at the points C₁₁
Any convenient form of case may be used which has a suitable ear piece to
protect the plate from injury or contact with foreign substances. The connections
of this instrument with the circuit may be made in the usual manner.
This improved microphone or apparatus for causing undulations in a current of
electricity in a telephonic circuit is shewn in Figure 5. G is the block or stand
carrying the carbon blocks H and the pencil I fitted loosely into them and free to
move, Secured to the pencil I are the paddles K upon which the air waves
impinge and cause the desired movement of the pencil F. Figure 5ª is a cross
section upon line Y Z. In figure 6 the pencil with the spiral flange is shown, the
action being similar to that of Figure 5.
In Figure 7 the pencil 1 is dispensed with and the Carbon block L is secured to
the stand G which may be of cork wood or of any suitable material; there is a
hole through the centre of both blocks, into which loosely fits the small piece of
carbon M over which again is placed the second carbon block N which carries the
paddles K secured to it in any convenient manner One wire W is connected to
each of the blocks and the action is the same as Figure 5.
Having now described the invention as communicated to me by my. foreign
correspondent and the method of performing the same I claim.
First The combination with an electro magnet of a plate of iron or steel or other
material capable of inductive action placed in front of the pole of the magnet and
close to it making an angle with the axis of the coil of the electro magnet, the
plate being attached at one point at or near its periphery or edge to a fixed
support and resting at another point of its periphery upon another fixed support 5
substantially as set forth.
Second The combination with a magnet having a coil or coils upon the end or

page_text: ends of the magnet nearest to the plate, of a plate of Iron or steel or other
material capable of inductive action, placed close in front of the pole of the magnet
but not touching it and making an angle with the axis of the coil in the magnet,
the plate being attached at one point at or near its periphery or edge to a fixed
support and resting at another point of its periphery upon another fixed support
substantially as set forth.
Third The combination with a magnet or electro magnet, substantially as
described, of a plate lying at right angles to the axis of the magnet, the plato
being secured at one point at or near its periphery or edgo to a fixed support and
resting at another point of its periphery upon another fixed support, substantially
as described.
Fourth The combination with a Horse-shoe magnet of a plate, substantially as
described, securod at a point at or near its periphery or edge to one limb of the
magnet and extending over the other limb upon which is the coil and resting at
another point of its periphery upon another fixed support.
Fifth The combination with a microphone of the paddles K or equivalent device
capable of being acted upon by the air waves substantially as and for the purpose
set forth.
Sixth The application to the loose or moveable part of a microphone of the
principle of the screw substantially as and for the purpose set forth.
Seventh The application to the loose or moveable point of a microphone of the
principle of the paddle wheel substantially as and for the purpose set forth..
In witness whereof I the said Alfred Julius Boult have hereunto set my hand
and seal this second day of January in the year of our Lord one thousand eight
hundred and eighty four
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