IMPROVEMENTS IN TELEPHONES
Year: 1878

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
.County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
TELEPHONES." A communication from abroad by Frederic Allen Gower and
Cornelius Roosevelt, both of Paris, in the Republic of France.
Sealed the 14th January 1879, and dated the 3rd October 1878.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 3rd October 1878.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN TELEPHONES." A communication from abroad by
Frédéric Allen Gower and Cornelius Roosevelt, both of Paris, in the Republic of
France.
This Invention has for its object enabling telephones to be constructed with
novel means for producing an audible signal to call attention in a practical manner
and under favourable conditions without the assistance of any auxiliary apparatus
or of any telegraphic wires, batteries, magneto-electric machines, or the like.
The arrangement employed according to this Invention also has the effect of
increasing the power of reproducing the words transmitted.
This system is based on the employment of a musical instrument (such for
example as a reed or tongue) in combination with the telephone in such a manner
that the mouth-piece or cone serving for the transmission of the words may be
utilised for the passage of a current of air acting upon the musical instrument so
as to produce an audible signal to call attention.
The mouth-piece of the telephone is thus caused to serve two purposes, namely,
the transmission of words as well as of a current of air to produce the signal to
call attention.
Another essential part of this Invention consists in arranging the musical instru-
ment destined to be set in vibration by the current of air blown through the mouth-
piece of the telephone inside the box of the telephone underneath the vibrating

page_text: plate, the said box of the telephone being perforated with one or more holes to
enable the air to pass through in the form of a current. The musical instrument
may however be arranged above the vibrating plate, which in that case is not
perforated.
According to one mode of carrying out this Invention the vibrating plate is
perforated with a hole, which may be of an oblong or any other convenient shape.
The said plate is fixed underneath a recess formed in the under side of the cover of
the wooden box of the telephone with a washer of india-rubber extending all round
its edge, and the small end of the conical mouth-piece opens into or is in direct
communication with the hollow space or recess provided above the vibrating
plate.
To the under side of the vibrating plate there is soldered or otherwise attached
a tube containing a flexible tongue or reed, and one or more holes are formed in the
bottom of the box of the telephone. The poles of a permanent horse-shoe magnet
for example are arranged and connected in the usual manner with the coils of the
telephone.
On applying the mouth to the conical mouth-piece and blowing into it, a violent
current of air is produced, which passes through the hole in the plate into the tube,
causing the tongue in the said tube to vibrate the air thence issuing at the lower
end of the said tube and finally escaping through the hole or holes provided in the
box.
The sound produced is transmitted to the receiving apparatus, where it is repro-
duced with great intensity & forms a signal to attract the attention of the person
or persons who are to receive the message to be subsequently delivered through the
apparatus by speaking in the ordinary manner, but which are transmitted with
greater intensity of sound.
In lieu of soldering or otherwise attaching the tube to the under side of the
vibrating plate, the said tube with its reed or vibrating tongue may be arranged at
one end of a lever in such a manner that the end of the tube may be pressed against
the under surface of the plate when required by pressing a key at the other end
of the lever at the moment when it is desired to make the signal to attract
attention.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
2nd April 1879.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN TELEPHONES." A communication from abroad by
Frederic Allen Gower and Cornelius Roosevelt, both of Paris, in the Republic of
France.
The said Invention relates to the construction of telephones with improved
arrangements of apparatus or devices for producing audible signals to call attention,
and it consists in the combination in a telephone of a perforated plate or diaphragm
and a reed or tongue or other vibrating musical instrument arranged beneath the
same in such a manner that by the act of directing.
. a current of air into the
ordinary mouth-piece or cone, the reed or tongue or other like instrument is set in
vibration and an audible sound is obtained, which is reproduced by the telephone
at the receiving end of the line. The employment of the reed or tongue or other
like vibrating instrument is attended also with the collateral advantage that it has
the effect of increasing the power of the telephones to which it is applied in the
reproduction of the articulate sounds transinitted.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same, and for that purpose shall refer to the
two Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in both the Figures.
Figure 1 of the accompanying Drawings represents a vertical section of a portion
of a telephone with the said Invention applied thereto, and Figure 2 is a detail
plan of the vibrating plate of the telephone detached.
A is the plate or diaphragm which is secured underneath a hollow space or recess a
formed in the under side of the cover B of the box of the telephone. This plate is
formed with an aperture c, which in the example illustrated is of an elongated shape,
but may be made of any other convenient forin, and to the under side of the plate
there is soldered or otherwise attached a tube C containing a vibrating tongue or
reed d, which is set in vibration by directing a current of air into the mouth-piece D,
the air passing through the aperture c and acting upon the tongue or recd, thus
producing a musical note, which is transmitted to the apparatus at the receiving
end, and there reproduced with great intensity. By these means an audible signal
is produced to attract the attention of the person or persons who are to receive the
message, which is to be subsequently delivered through the apparatus by speaking
in the ordinary manner, but which, when the tongue or reed is used, is emitted with
greater intensity of sound. One or more apertures E are provided in the bottom
of the box for the escape of the air put in motion in giving the signal, the arrows
indicating the course. of the air from the inlet D to the outlet or outlets E.
It is assumed that the poles of a permanent horse-shoe magnet are situate beneath
the plate A at g, and connected with the coils of the telephone in the usual manner,
or that an equivalent body capable of inductive action is employed in substitution
for the permanent magnet, this portion of the apparatus being omitted from my
Drawings for the sake of simplicity. A washer of india-rubber or other suitable
material may be interposed between the plate A and the cover B, the said washer
extending all round the edge of the plate.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,―
The combination in a telephone of a perforated plate or diaphragm, and a reed

page_text: or tongue or other vibrating musical instrument arranged beneath the same, substan-
tially as and for the purpose herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this First day of April, One thousand
eight hundred and seventy-nine.
J. HENRY JOHNSON. (L.S.)