AN IMPROVED MICRO-TELEPHONIC APPARATUS FOR INTENSIFYING SOUND DURING TRANSMISSION
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Robert Henelade Courtenay at the
Office of the Commissioners of Patents on the 17th March 1880.
ROBERT HENELADE COURTENAY, of 166, Fleet Street, in the City of London.
"AN IMPROVED MICRO-TELEPHONIC APPARATUS FOR INTENSIFYING SOUND DURING
TRANSMISSION."
This Invention has for its object an improved micro-telephonic apparatus for
intensifying sound during transmission.
In constructing my improved apparatus an iron or steel bobbin or core with a
soft iron or other base is, after being polished with a resisting medium, coiled with
a number of lengths of wire insulated and connected by one end of each length to
the bobbin.
The bobbin or other form of core of iron or steel is connected with a pendulum
or spring or springs of any suitable metals, such as silver, gold, platinum, platinized
silver, steel, iron, or any metal or combination of metals either in the form of
spiral or flat springs coated with a resisting medium or otherwise; or in lieu of
the springs before mentioned a disc of any metal of greater resistance can be
suspended as hereinafter described, either singly or combined with springs, the
same being fitted in any suitable way to obtain delicate vibratory motion with the
object of getting microphonic effects with less resistance as compared with carbon
as generally used.
There are two ways of mounting the combination, one being in a suitable
strong case connected with ball and switch, and the usual fittings without a glass
or other chamber, excepting the case, as hereinafter described.
The other method is to mount with a glass or other chamber in a suitable case,
as also hereinafter described.
I also employ compounds and alloys of metals, as described, prefering metal of
the highest in combination with metals of the lowest resistance, the combination
being by electro deposit or otherwise.
According to another method in preference-to-carbon as-now-in use in telephonic
transmitting I take various carbonates or other suitable salts of metal, and the
metals also in a finely divided state, and also an alloy of metals of variable electrical
resistance treated in such a manner as to be easily mixed with water or other
[Driss 971

page_text: fluid, and forming a compound metallic substance easily moulded to the required
size and form.
A perforated disc of the metallic compounds is suspended between two conducting
screws, and the screws adjusted to the pendulum of alloy, which is easy of
accomplishment, the screws being turned with both hands until they meet the
pendulum of alloy or other substance employed between the conductors, which
conductors enter the compound disc or metal pendulum.
In carrying my first mentioned method into effect I use metallic discs, such as
bismuth, lead, or any other metal highly polished with a carbonaceous compound,
the conducting screws being also coated or polished with an alloy of greater
resistance than the metals used as conductors. I also employ a soft iron or steel
bobbin highly polished with the metallic compound, around which I wind several
lengths of insulated copper wire of any suitable guage. Each wire is soldered to
the polished iron or steel bobbin or otherwise metallically connected.
The other ends of the lengths of wire are connected to one of the connecting
screws leading to the battery. Another wire is connected with the metallic
bobbin, and also to a telephone, for the purpose of transmission, the coupling being
according to the number of instruments in circuit.
The conducting screws are passed through supports of ebonite or wood, and
springs (or other mode of connecting) attached to the conductors.
The ebonite or other supports are secured to a platform of wood, ebonite, or
other material supported on insulators in a glass dome or other suitable form of
chamber (in any other substance), which is placed over the apparatus.
If it is necessary to use the transmitter with an induction coil of the ordinary
construction the interior of the glass dome or other form of chamber is coated with
silver or other conductor, which renders the chamber a condenser when connected
with the primary circuit in the usual way.
The carbonates I have used, together with the alloy and metals in a fine state
of division, are carbonate of silver, pure silver powder, and an alloy, the com-
position of which consists of bismuth, lead, zinc, and mercury.
I do not bind myself to the use only of the above mentioned alloy, powder, or
carbonates, but to the general combination of the parts, for the purpose to which
the same can be applied.