IMPROVEMENTS IN
Year: 1884

page_text: I KAZIMIR STANISLAS DEMBINSKI of
do hereby declare the nature of my
MICROPHONES to be as follows:-
"
Brussels in the Kingdom of Belgium
said invention for "IMPROVEMENTS IN
The apparatus consists of a wooden box of oblong shape, closed by a lid fixed by
hinges to the top or to one side of the box. In this box one or more drawers are
placed containing the carbons; these may be placed inside or outside the drawers,
they may also be arranged in the interior of one drawer and on the exterior of
another. The drawer is a box of thin wood lined inside with petroleum lamp-black
for the purpose of increasing the resonance. It moves in two lateral slides.
Against the long sides of the drawer are placed two carbons of suitable shape
provided with semicircular recesses intended to receive the transverse carbous.
The longitudinal carbons are attached to the bottom of the box either by means of
glue or in any other suitable manner, and the transverse carbons are placed loosely.
in the recesses. The conducting wires are attached to one end of each longitudinal
carbon. The cover of the drawer is constructed of a thin piece of pine or other
suitable wood, also coated on the inside with petroleum lamp-black. This wooden
lid is provided with two openings resembling those of a violin.
It is supported in a wooden frame, bearing two small cross pieces designed to
support the vibrating strings. These strings may be of any suitable material but
good results are obtainable with little spiral springs of copper or of steel. They
are attached to metal holders or preferably to pegs like those of a piano or violin,
so that each of the springs may be tuned to vibrate respectively to a given note of
the scale. The complete scale is not indispensable and the springs may respond to
only certain notes of the scale. But it is preferable to have at least one complete
octave. On the bottom of the instrument are stretched another set of strings
similar to the first.
The apparatus is provided with one or more induction coils the thick wire of
which has a diameter of about a millimetre and the thin wire a diameter of about
one twelfth of a millimetre. There are as many coils as there are drawers. The
conducting wires may terminate in platinum wires soldered on to them so as to
avoid any oxidation at the points of contact with the carbons.
It is obvious that this arrangement furnishes an instrument of great power of
resonance, not only the drawers but also the box itself acting as sounding boxes.

page_text: The outer envelope of the instrument consists of a wood frame covered with fine
wire gauze. The drawers may be arranged as described or they may be placed
inversely. In this case the lid becomes the botton and so on. When in action
the positive current from the first terminal after passing through the induction coil
traverses the right hand longitudinal carbon. It then passes through the transverse
carbons which convey it to the lefthand longitudinal carbon and from thence to the
second terminal forming the negative pole. The induction current passes directly
through the line wherein the apparatus is interposed and the two main terminals
are arranged accordingly. Two other terminals arranged side by side with the
previous ones are intended for the attachment of two telephones.
The carbons may be replaced by platinum plates arranged in a similar manner,
and the vibrating strings may be replaced by a steel comb giving all the notes of
the chromatic scale and resembling that used in a musical box. With this arrange-
ment however the transmission does not operate as strongly as with the strings.
When the vibrating strings are replaced by a steel comb this latter is fixed by
means of screws to one of the sides of the sounding box; or two combs may be
inserted when drawers are used containing the carbons inside, in this case one
comb is placed above and the other below the box. Lastly the instrument may be
furnished with a bell and a commutator of any suitable construction and it may
be constructed in various modifications so as to adapt it to the requirements of the
various telegraphic and telephonic systems.

page_text: ول
and in what
I, KAZIMIR STANISLAS DEMBINSKI, Brussels, Belgium do hereby declare the
nature of my said invention for "IMPROVEMENTS IN MICROPHONES
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
.
The present application for Letters Patent has for its object certain improvements
in microphones of the type known as "Dembinski." The improved apparatus is
constructed as follows.
In the accompanying drawings, Figure 1 is a longitudinal section of the apparatus
showing two drawers. Figure 2 is a transverse section of the same Figure 3 view
of lid, Figure 4, plan view of lid of drawer, Figure 5 plan view showing the
arrangement of the carbons in the drawer, Figure 6 longitudinal view of drawer,
with carbons placed inside, Figure 7 transverse section of drawer with carbons
placed outside.
The apparatus consists of a wooden box A of oblong shape, as shown in Figure 1,
closed by a lid K, Figure 3, fixed by hinges to the top, or to one side of the box.
In this box one or more drawers B are placed containing the carbons CD. These
may be placed outside the drawers, as shown in Figure 7, or inside as in Figure 6,
they may also be arranged in the interior of one drawer, and on the exterior of
another.
The drawer is a box of thin wood lined inside with lamp black for the purpose
of increasing the resonance. It moves in two lateral slides. Against the long sides
of the drawer are placed two carbons C of suitable shape, shewn in Figures 1, 2, 5,
and 7, and provided with semi-circular recesses intended to receive the transverse
carbons D. The longitudinal carbons are attached to the bottom of the box either.
by means of glue, or in any other suitable manner, and the transverse carbons are
placed loosely in the recesses. The conducting wires are attached to one end of
each longitudinal carbon.
.
The cover E. of the drawer as shown in Figure 4 is constructed of a thin piece
of pine or other suitable wood, also coated on the outside with lamp black. This
wooden lid is provided with two slits, resembling those of a violin.
It is supported in a wooden frame, bearing two small cross pieces F, designed to
support the vibrating strings G; these strings may be of any suitable material but
good results are obtainable with little spiral springs of copper or of steel. They
are attached to metal holders H or preferably to pegs like those of a piano or
violin, so that each of the springs may be tuned to vibrate respectively to a given
note of the scale. The complete scale is not indispensable, and the springs may
respond to only certain notes of the scale, but it is preferable to have at least one
complete octave; on the bottom of the instrument are stretched another set of
strings similar to the first.

page_text: The apparatus is provided with one or more induction coils J, 'the thick wire of
which has a diameter of about a millimetre, and the thin wire a diameter about
one twelfth of a millimetre. There are as many coils as there are drawers. The
conducting wires may terininate in platinum wires soldered on to them, so as to
avoid any oxidation at the points of contact with the carbons.
It is obvious that this arrangement furnishes an instrument of great power of
resonance, not only the drawers, but also the box itself acting as sounding boxes.
The outer envelope K of the instrument consists of a wood frame covered with
fine wire gauze L. The drawers may be arranged as described, or they may he
placed inversely. In this case, the lid becomes the bottom, and so on.. The form
and dimensions of the apparatus, and the number of carbons may be modified to
adapt the apparatus to the requirements of any given telegraphic or telephonic
system.
The positive current from the first terminal a when in action, after passing
through the induction coil, J, traverses the right hand longitudinal carbon. It
then passes through the transverse carbons which convey it to the left hand
longitudinal carbon, and from thence to the second terminal b forming the negative
pole. The induction current passes directly through the line wherein the apparatus
is interposed, and the terminals c and d are arranged accordingly. Two other
terminals c¹ and d' arranged side by side with the previous ones are intended for
the attachment of two telephones.
The carbons may be replaced by platinum plates, arranged in a similar manner,
and the vibrating strings may be replaced by a steel comb giving all the notes of
the chromatic scale, and resembling that used in a musical box. With this arrange-
ment however the transmission does not operate as strongly as with the strings.
When the vibrating strings are replaced by a steel comb, this latter is fixed by
means of screws to one of the sides of the sounding box; or two combs may be
inserted when drawers are used containing the carbons inside; in this case one
comb is placed above and the other below the box. Lastly the instrument may be
furnished with a bell, and a commutator of any suitable construction, and it inay
be constructed in various modifications, so as to adapt it to the requirements of the
various telegraphic and telephonic systems.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1st The combination of parts forming the apparatus comprising an induction
coil, one or more drawers containing carbons arranged as specified, and vibrating
strings, the whole contained in a box also furnished with vibrating strings, and,
as well as the drawers acting as a sounding box, substantially as described and
shown.
2nd The arrangement of the drawer containing the carbons, and the method of
connecting the longitudinal and transverse carbons, by means of small semi-circular
recesses in the former into which the latter fit loosely.
3rd The arrangement of the drawers so as to form sounding boxes, and furnishing
them with vibrating strings on a special support, each representing a given note of
a complete or partial scale.
4th The use of lamp black for lining the interior of the box in order to increase
its powers of resonance.
5th The use of vibrating strings formed of fine copper or steel spiral springs
substantially as described.
6th The use of one or more induction coils having one wire of one millimetre
in diameter, and the other one twelfth of a millimetre substantially as described.
7th The use in a microphone of longitudinal platinum plates furnished with
notches into which fit transverse platinum plates, arranged in the same manner as
the carbons as described in claims 2 and 3.

page_text: 8th The use in a microphone of one or more steel combs, producing all the notes
of the chromatic scale, and screwed to the sounding boxes in place of the vibrating
strings, as claimed in claim 5.
Dated this sunday of February 1000.
WM P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
and 323, High Holborn, London,
Patent Agents for the Applicant.