IMPROVEMENTS IN AND APPLICABLE TO TELEPHONES AND TO PHONOGRAPHIC APPARATUS CONNECTED THEREWITH
Year: 1880

page_text: LETTERS PATENT to Friedrich Hermann Felix Engel, Civil Engineer and .
Patent Agent, in the City of Hamburg, Germany, for an Invention of
"IMPROVEMENTS IN AND APPLICABLE TO TELEPHONES AND TO PHONOGRAPHIC
APPARATUS CONNECTED THEREWITH." A communication from Wilhelm
Klinkerfues, Doctor of Philosophy, Professor and Director of the Royal
Observatory at Göttingen, in the German Empire.
PROVISIONAL SPECIFICATION left by the said Friedrich Hermann Felix
Engel at the Office of the Commissioners of Patents on the 13th February
1880.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. "IMPROVEMENTS IN AND APPLICABLE TO TELEPHONES
AND TO PHONOGRAPHIC APPARATUS CONNECTED THEREWITH." A communication
from Wilhelm Klinkerfues, Doctor of Philosophy, Professor and Director of the
Royal Observatory at Göttingen, in the German Empire.
This Invention relates, firstly, to the application of a galvanic current of a battery
to speaking telephones, but in such a manner that no opening and closing of the
current takes place at the contact parts. The galvanic apparatus remains constantly
closed, even while the telephone is at work, but the size or amount of the contact
varies in such a manner that the latter is dependent from the size of the amplitude
or arc of oscillations of the diaphragm of the telephone. This difference of size of
the contact is produced by the application of a platin pin attached to the under side
or bottom of the diaphragm, which pin has a broad base widening out from its
point, which dips into a tube or pipe filled with quicksilver placed within the body
of the telephone. One pole of the battery is in connection with the diaphragm, the
other with the quicksilver of the pipe.
The Invention further relates and has for object to reinforce the vibrations of the
current by a combination of several diaphragms which are intercalated between
elements of the battery of the receiving station, and by there applying one bell in
common to the different diaphragms.
The before described arrangements produce at the receiving station sounds and
words of such strength that a phonograph may be connected to the bell, the vibra-
tions of which will distinctly be transferred or transported to the tin foil of the
instrument

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Friedrich Hermann Felix Engel in the Great Seal Patent Office on
the 13th August 1880.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. "IMPROVEMENTS IN AND APPLICABLE TO TELEPHONES
AND TO PHONOGRAPHIC APPARATUS CONNECTED THEREWITH." A communication
from Wilhelm Klinkerfues, Doctor of Philosophy, Professor and Director of the
Royal Observatory at Göttingen, in the German Empire.
According to the experience gained up to this day it can be considered for
certain that the reproduction of a sound, as, for example, 2, m, l, r, etc., requires
the reproduction of the amplitude or arc of oscillation, with all the variations to
which it is subject, for the formation of the sound, whilst for the reproduction of a
musical tone only the reproduction of the duration of oscillation is required. For
this reason the telephone of Reiss, invented in 1860, was only able to reproduce
inusical tones, for with this instrument of Reiss' the galvanic current of a battery
was with each double oscillation of the diaphragm closed in such manner that the
strength of the currents could not vary, but remained very nearly the same. Bell
attained the required difference of the arc of oscillation by application of magnetic
induction, in consequenco of which he was enabled to transmit the speech. The use
of magnetic induction has, however, the disadvantage that the transinitting currents
are weak, and are casily disturbed by outer influences.
The present Invention makes use again of the application of a galvanic current
of a battery for the operating of speaking telephones, but in such inanner that
alternative opening and closing of the current does not take place as formerly.
The galvanic circuit remains constantly closed whilst the telephone is at work, but
the size or amount of the contact of the circuit varies in such manner that the same
is dependent from the size of the amplitudes or arcs of oscillation of the diaphragm
of the telephone. By this arrangement a small amplitude of oscillation of the
diaphragin of the instrument spoken into allows only of a weak current to pass (as
the contact surface is small) whilst a larger amplitude produces a greater contact
surface and causes a stronger current to pass to the receiving diaphragm.
Fig. 1 of the annexed Sheet of Drawings represents this part of the Invention.
The telephone is in communication with a battery in such manner that the negative
pole is in connection with the metal diaphragın m fastened between non-conducting
parts of the instrument. Instead of a steel magnet and wire core, as with Bell's
telephone, a narrow bent iron pipe is placed within the instrument, which pipe
is filled with mercury, and is connected to the positive pole of the battery.
T'o
the underside of diaphragmn m one or several conical shaped platina or other metal
studs or pins are fastened, which constantly dip into the quicksilver within pipep
and so forms or form the contact of the transmitting line. The dip of stud or pin
or pins p can be regulated by a set screw S placed in the outer closed arm of tuber,
and the said pins or studs are not necessarily points but wedge shaped projections
having thin points and widening to the base. When the diaphragm is put in
oscillation by being spoken to a vibrating variable resistance is produced at the
contact place of pin and mercury, and consequently currents of vibrating or variable
strength must pass through the transmitting line. By these currents of vibrating
strength the diaphragm of the receiving telephone is put in oscillation, which in
duration, as well as amplitude, depend upon and correspond with those of the
diaphragm of the sending instrument.
The mercury can also be placed within a hollow channel of the steel magnet of
a telephone after Bell's or Siemens' system. This is shown in Fig. 2 of the Drawing.
The outer tube ris in this case screwed to the magnet M, and is in connection with

page_text: the wire core K, which latter communicates with the positive pole of an element
of a battery. For reinforcing the oscillations by several imitating diaphragms the
latter may be made of mica, as with the phonograph, and be furnished at the bottom
side with a piece of india rubber g (see Fig. 2) or the like. The oscillations of the
diaphragm are by this piece g transmitted to a springs furnished at its free end
with one or more pins p which dip into the mercury contained in the hollow
maguet M, and which is or are in communication with the line. The pins p, if
there are several used, are connected to each other by the small iron plate i. When
the diaphragm m is spoken to the springs imitates the oscillations of m, and the
different depth of dip into the mercury of the pins p produces the variations of
the intensity of the current, which are through the mercury channel led to wire
core K. Several similar telephones may be intercalated in the line between
elements of the battery, and each may by an india-rubber pipe L connected to the
mouth piece p be in communication with the narrow end of one hearing trumpet
for gathering the sounds and words from all single telephones. This hearing
trumpet may be put in connection with a phonographic instrument for bringing the
words or cominunications on the tin fuil of this instrument in a manner well
known.
Having now described the nature and particulars of the said Invention, I
claim,―
First. The application of an uninterrupted galvanic current to speaking telephones
whilst in use.
Second. With telephones the application of one or more metal tubes filled with
mercury, into which dip platina or other metal pins, either connected to the
diaphragm of the instrument or moved by the oscillations of same, for the purpose
of producing a contact of vibrating or varying size, substantially as and for the
purpose herein set forth and shown by the Drawings.
Third. The reinforcement of the variations of tho current by several imitating
diaphragms of several telephones intercalated between elements of the battery, sub-
stantially as described and explained in reference to and shown by the accompanying
Sheet of Drawings, and
Fourth. The gathering of the sounds or words of all imitating diaphragms in ono
hearing trumpet, substantially as described.
In witness whereof, I, the said Friedrich Hermann Felix Engel, have hereunto
set my hand and seal, this Ninth day of August, in the year of our Lord
One thousand cight hundred and eighty.
.