Improvements in Telephonic Transmitting Instruments.
Year: 1885

page_text: Improvements in Telephonic Transmitting Instruments.
I SILVANUS PHILLIPS THOMPSON of 20 Arundel Gardens Notting Hill in the
County of Middlesex Doctor of Science and Professor of Experimental Physics do
hereby declare the nature of said Invention for IMPROVEMENTS IN TELEPHONIC
TRANSMITTING INSTRUMENTS to be as follows:-
My Invention consists in constructing or providing telephonic transmitters with
microphones of a peculiar kind so that no diaphragm or tympanum or anything
which can operate as such is necessary and my Invention is applicable both to such
cases as those mentioned in my Specification of Letters Patent No 3808 of 1882 in
which reflectors reverberators or mouth tubes are employed and also to cases
wherein no such adjunts are employed. I construct these microphones of tubular
form, so that they may be small weight in proportion to their size.
And they may
be made either of suitable metals or alloys or of some conducting,substance such as
magnetite or coke carbon possessing metallic conductivity. The tubes are laid
supported or suspended in light contact with one another or with suitable con-
ductors or contact wires or pieces so that the electric current passes through them
and through their contact surfaces. The tube are placed so that the air wave of
the voice pass through or impinge upon or around them and so that the said air
waves impart to the tubes the requisite movement.
J. HENRY JOHNSON,
Agent.

page_text: Improvements in Telephonic Transmitting Instruments.
I SILVANUS PHILLIPS THOMPSON of 20 Arundel Gardens Notting Hill, in the
County of Middlesex Doctor of Science and Professor of Physics 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:-
My Invention consists in constructing or providing telephonic transmitting
instruments with microphones of a peculiar kind so that no diaphragın or
tympanum or anything that can act as such is necessary and my Invention is
applicable both to such cases as those mentioned in my Specification of Letters
Patent N° 3808 of 1882 in which reflectors reverberators or mouth tubes are
employed and also to cases wherein no such adjuncts are employed. I construct
these microphones of tubular form so that they may have small weight in pro-
portion to their size-They may be made either of suitable metals or alloys or of
some conducting substance such as coke carbon possessing metallic conductivity.
I find that they can be conveniently and efficiently prepared from parchmentised
cellulose or similar material coked or carbonized by heating in a closed vessel from
which air is excluded and into or through which hydrocarbon vapour is passed as in
the processes for the manufacture of conductors of incandescent lamps but I make
no claim to this process as it is well known. The tubes are laid supported or
suspended in light contact with one another or with their supports and in contact
with or connected to suitable conductors or contact wires or pieces so that the
The
electric current passes through them and through their contact surfaces.
tubes are placed so that the air waves due to the voice or other sound pass through
or around or impinge upon them and so that the said air waves impart directly to
the tubes the requisite minute movements.
I will describe with reference to the accompanying diagrams manners in which
the tubes may be arranged in practice but I wish it to be understood that I do not
limit myself to the precise arrangements here shewn as they may obviously be
varied without departing from the nature of my Invention as hereinbefore
explained and hereinafter claimed.
Figure 1 represents one of the aforesaid hollow tubes a suspended in loose
contact upon pins or projections b of platinum or carbon or other suitable con-
ducting material held in supports c and forming part of an electric circuit of which
dd represent the wires.
Figure 2 represents a multiple arrangement of the said tubes a the wires d
being connected to the supports c which carry the projections 6 for all the tubes a.
Figure 3 represents another arrangement in which one tube a rests lightly
poised upon a second tube a² the current flowing through their point of contact.
The one wire d is connected to the rod or wire d' which by the links e supports
the tube a the said links engaging with the wires or projections a³ one on each
side of the tube a.
Figure 4 represents a tube a hung by a hook f (to which the wire d is attached)
so as to rest lightly within and against a larger tube a² with which it makes

page_text: contact. The other wire d is attached to the tube a³ and completes the circuit.
The speaker speaks to the outside or his voice may be directed by a funnel through
the larger tube.
Figure 5 represents two curved tubes a a slung on wire supports g (to which the
wires d d are respectively attached) and forming a sort of cradle in which is laid a
tube a which makes contact with both the tubes a and completes the circuit.
Figure 6 represents four tubes two of which a are supported on vertical supports
the two others a' resting on them. The tubes a² may be restrained from rolling or
being displaced by light guides of wire or wood as shewn at h admitting however
of slight vibration. The current comes up one vertical support (say that at d²) and
goes down one on the other side (say that at d³) and so passes through the contacts
between the tubes. The speaker speaks above or at one side of this arrangement
or through a mouth piece. It will be understood that the arrangements shewn may
be mounted in any suitable carrier or casing with an inlet orifice or mouthpiece or
the like to admit the air waves to act upon the tubes.
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:
First. In telephonic transmitters tubular conductors in loose contact with each
other or with their supports and forming part of an electric circuit and acted upon
directly by the air waves substantially as herein before described and illustrated by
the examples shewn in the accompanying drawings.
Second. The several arrangements of tubes constituting microphonic telephone
transmitters as hereinbefore described and illustrated by the accompanying
drawings.