IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF TELE- PHONES AND APPARATUS CONNECTED THEREWITH
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Charlton James Wollaston and Adam
Scott at the Office of the Commissioners of Patents on the 17th December
1878.
CHARLTON JAMES WOLLASTON, of 37, Chepstow Place, Bayswater, in the County
of Middlesex, and ADAM SCOTT, of 14, Elgin Crescent, Notting Hill, in the County
of Middlesex. "IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF TELE-
PHONES AND APPARATUS CONNECTED THEREWITH."
1. We combine in the form of telephone known as the box telephone a bell or
other "call" apparatus furnished with push button, automatic, or other switch, and
one or more hand telephones, the whole being so arranged that the bell or other
call is left in circuit when the telephones are not in use, and is cut out of circuit
when the telephones are used for communication.
2. We attach to such box telephones a flexible tube of india rubber or other
suitable material, fitted with a mouth piece for greater convenience of speaking
and hearing; the tube may be divided into two or more branches, so as to allow
of several persons hearing or making use of the telephone at the same time.
3. When a box telephone is used alone as sender and receiver, the necessaryý
switch or switches for placing the bell in or out of circuit may be moved by hand,
or by an arrangement attached to or actuated by the flexible tube or mouthpiece.
4. Either galvanic electricity obtained from a battery or magneto electricity may
be used for sounding the bell or other call when the latter is used.
We prefer to
include the magneto machine in the box containing the telephone.
5. We find that the quality and clearness of articulation is improved in box
telephones by placing behind the diaphragm a guard or backing of wood, metal, or
other suitable material, so arranged as to leave only a small space between the
backing and the diaphragm, the guard or backing being so made as to allow of the
proper arrangement of the magnets and coils, and in some cases in order to deaden
the reverberation caused by the box of the telephone a packing preferably of soft
material may be used.
6. We sometimes place in front of the diaphragm of a box telephone a plate of
ebonite, or metal, or other suitable material with an opening opposite the speaking

page_text: tube. We thus obtain an external chamber that is not affected materially by
moisture or difference of temperature.
7. The quality of the sound produced by a telephone depends much upon the
proper thickness and degree of tension of the diaphragm. We have found it
desirable therefore to attach the diaphragm to a metal ring which enable it to be
more securely held.
8. The diaphragms are usually formed of iron, but we sometimes form them of
other suitable materials, and attach to such diaphragm pieces of soft wire to be
acted upon by the magnet.
9. In the construction of hand and box telephones in which horse shoe magnets
are used, it is usual to fix to each pole a piece of iron upon which a coil of fine
wire is placed. Poles may also be formed in one piece with the magnet. In
both cases the poles are some distance apart, and act upon the diaphragm at two
points away from the centre thereof. In order to obtain the action of the magnet
as near as possible at the centre of the diaphragm, we extend such pole pieces
towards the centre, and we prefer to solder these extended poles together,
separating them only by a piece of brass or other non-magnetic material. Each
pole piece may if desired be constructed in one piece, so as to be capable of being
brought near the centre as described...
"
10. We sometimes prefer to bring one pole of the magnet near the centre by an
extension, such as previously described.
11. In some cases we place one pole (as ordinarily attached to the magnet)
opposite to the centre of the diaphragm, and then the other pole near to or in
contact with the outer part of the diaphragm. This latter pole may be without a
separate pole piece or without a coil.
12. In cases when we fix (as in paragraph No. 11) one pole opposite the centre of
the diaphragm, we sometimes bring the other pole near the first one by a similar
extension, as described in paragraph No. 9.
13. We sometimes use a combination of two or more horseshoe magnets all
acting upon the same diaphragm, and with their poles brought towards the centre
in the manner described in paragraph No. 9.
14. We sometimes use two or more horseshoe magnets with only one pole of each
brought by extensions to the centre of the diaphragm. The other poles may in this
case be used as referred to in paragraph 13.
15. To suit the convenience of persons of different stature we arrange the box
telephone in a suitable slide, enabling the position of the telephone to be adjusted,
and we make such slides the means of forming the connections which place the box
telephone and apparatus in the electric circuit. In other cases we arrange the
mouthpiece of the flexible tube attached to the box telephone, so that it can be
held on one or other of several varying positions by a clip or clips or other
contrivance, enabling the adjustment of the mouthpiece to the required height.
16. In box telephones we sometimes make openings for the escape of the air
when the tube or mouthpiece is spoken into. These openings may be made from
the external chamber in the neighbourhood of the diaphragm, as may be made in
the diaphragm itself.
17. In order as much as possible to prevent vibrations from sounds or other
external causes being communicated to the telephone, we protect or insulate it from
such disturbing influences by the use of india rubber or other suitable material.
18. During thunderstorms the fine wire coils of telephones are liable to be fused
by discharges of electricity. To prevent this happening we provide in connection
with our apparatus a suitably formed lightning guard or protector.
19. In cases in which telephonic communication is desired with one or more
stations between the extreme ends of a telephonic circuit, we arrange our apparatus
in such manner that by suitable switches any one station may call the attention of
any other station at will, and may carry on conversation with the desired station,
without any other station beyond the one intended to be communicated with
hearing the conversation which may pass.

page_text: 20. We sometimes use apparatus known as condensers to obviate the incon-
venience of speaking through the coils of any intermediate electric bell or signalling
apparatus when more than two stations are on one telephonic circuit.
21. To lessen the inconvenience of sounds in the telephone caused by induction
we introduce into the circuit water or other liquid resistance.
22. Instead of the usual diaphragm we sometimes use wires which may be
strained to any required tension, and attached to which are suitable pieces of iron
to be acted upon by the magnet.
23. We sometimes use pole pieces so shaped that the part on which the coils
are wound is parallel to the diaphragm, instead of being at right angles thereto.