IMPROVEMENTS FOR TRANSMITTING AND IN APPARATUS AND APPLIANCES INTENSIFYING SOUND FOR TELEPHONIC PURPOSES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Robert Henelade Courtenay at the
Office of the Commissioners of Patents on the 3rd March 1880.
ROBERT HENELADE COURTENAY, of 166, Fleet Street, in the City of London.
"IMPROVEMENTS
FOR TRANSMITTING AND
IN APPARATUS AND APPLIANCES
INTENSIFYING SOUND FOR TELEPHONIC PURPOSES."
This Invention has for its object an improved method of transmitting and
intensifying sound transmitted by electrical appliances herein under described.
In preference to carbon as now in use in telephonic transmitting, I take various
carbonates or other suitable salts of metals, and the metals also in a finely divided
state, and also an alloy of metals of variable electrical resistance, heated in such a
manner as to be easily mixed with water or other 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.
A further improvement consists in the use of 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 metal 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
Each wire is soldered to the polished
insulated copper wire of any suitable guage.
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, 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.

page_text: 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 and carbonate of lead, pure silver powder and an
alloy, the composition 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.