AN IMPROVED METHOD OF AND APPARATUS FOR AUGMENTING OR "
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine, Lakö
& Co., Patent Agents, Southampton Buildings London for an invention
c
of AN IMPROVED METHOD OF AND APPARATUS FOR AUGMENTING OR
" A com-
STRENGTHENING ELECTRIC CURRENTS FOR TELEPHONIC PURPOSES
munication from abroad by James Moser, of Berlin, Germany, Doctor of
Philosophy
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 31st March 1882.
WILLIAM ROBERT LAKE of the firm of Haseltine Lake & Co, Patent Agents,
Southampton Buildings London, "AN IMPROVED METHOD OF AND APPARATUS
FOR AUGMENTING OR STRENGTHENING ELECTRIC CURRENTS FOR TELEPHONIC
PURPOSES A communication from abroad by James Moser; of Berlin, Germany,
Doctor of Philosophy
"
This invention relates to electric telephonic circuits and apparatus connected
therewith chiefly designed for transmitting sounds from theatres, exchanges, or
other places. Hitherto the application of the telephone for theatrical purposes has
necessitated the use of a great number of conducting wires, and has consequently
occasioned a heavy outlay or expense for fitting up the apparatus. This defect is
due to the weakness of the telephonic current, which permits of only a very small
number of receivers being placed in the circuit of one transmitter.
The object of the said invention is to strengthen or augment the telephonic or
induced current in order to reduce the circuit to a single wire capable of supplying
a number of telephonic receivers, and thus effect great economy in the cost of
fitting up the apparatus. I obtain this result by the means and apparatus herein-
after described, which are also applicable to telephonic transmission to great
distances or through submarine cables.
In order to strengthen the telephonic current it is necessary to augment the
electro-motive force of the secondary circuit. For this purpose I place several

page_text: secondary coils in this circuit instead of a single one as hitherto practised. But
the increase in the number of secondary coils involves an increase in the number
of primary coils, and as the telephone is not operated by the current from the
battery but only by means of the human voice or other sound it is necessary to
augment the number of transmitters.
Thus the multiplication of the secondary coils which forms the essential feature
of my invention leads naturally to the multiplication of the primary coils and the
corresponding microphonic transmitters.
The grouping of the primary coils and their transmitters may be effected in
various ways. According to one arrangement four microphones are isolated and
cach supplied by a special battery; these form, with their primary coils, four
distinct circuits, but the induced currents generated in the four secondary coils,
are, according to my invention, united to form a single one, and thus constitute a
single circuit in which are placed a number of telephonic receivers, which number
may be very large. While in the methods hitherto employed it has only been
possible to use four receivers to one transmitter, it is possible by my invention to
operate fifty telephones on a single circuit and by means of a single element of a
"Leclanché" battery.
According to another arrangement four transmitters with their primary coils are
placed in derived circuits and are supplied by a single battery. And according to
a third arrangement the transmitters and their primary coils are arranged in series.
The primary coils and the secondary coils, each comprising an electro-motive force
and a resistance, may be grouped in a similar manner to the elements of a battery
according to any of the arrangements adopted for the latter.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
30th September 1882.
WILLIAM ROBERT LAKE of the firm of Haseltine; Lake, & Co, Patent Agents,
Southampton Buildings, London, "AN IMPROVED METHOD OF AND APPARATUS
FOR AUGMENTING OR STRENGTHENING ELECTRIC CURRENTS FOR TELEPHONIC
"
PURPOSES .A communication from abroad by James Moser, of Berlin Germany
Doctor of Philosopby.
This Invention relates to an improved method of and apparatus for augmenting
or strengthening electric currents for telephonic purposes.
Hitherto the application of the telephone for transmitting sounds from a theatre
or other place to a number of receivers has necessitated the use of a great number
of conducting wires, and has consequently occasioned a heavy outlay or expense
for fitting up the apparatus. This defect is due to the weakness of the telephonic
current, which permits of only a very small number of receivers being placed in the
circuit of one transmitter.
The object of the said invention is to strengthen or augment the telephonic or
induced current in order to reduce the circuit to a single wire capable of supplying
a number of telephonic receivers, and thus effect great economy in the cost of
fitting up the apparatus. I obtain this result by means of the apparatus hereinafter
described, which is also applicable to telephonic transmission to great distances or
through submarine cables.
In order to strengthen the telephonic current it is necessary to augment the
electro-motive force of the secondary circuit. For this purpose I place a number
of secondary coils in this circuit instead of a single one as hitherto practised. But
the increase in the number of secondary coils involves an increase in the number
of primary coils, and, as the telephone is not operated by the current from the
battery but only by means of the human voice or other sound, it is necessary to
augment the number of transinitters.
Thus the multiplication of the secondary coils, which forms the essential feature
of the said invention, leads naturally to the multiplication of the primary coils and
the corresponding microphonic transmitters.
The said invention is based upon the above described principles. In considering
the telephonic current as a function of the differential or variation of the primary
microphonic current, it has been found necessary to increase this variation by
multiplying the number of transmitters and primary coils, in order to augment the
electro-motive force of the induced circuit, while placing in the latter a num- of
secondary coils.
The grouping of the primary coils and their transmitters can be effected in
various manners, some of which are shown in the accompanying drawing by way
of example, and to illustrate the application of the said invention in connection
with theatres, exchanges and newspaper offices.
For the sake of clearness in the drawing the secondary coils are assumed to be
separated from the primary coils.
According to the arrangement shown in Figure 1, four microphones M², M²,
M³, M, are isolated and each supplied by a special battery, these form with their
primary coils B1, B2, B3, B4, four distinct circuits, but the induced currents generated
in the secondary coils S1, S2, S3, S4, are, according to this invention, united to form
a single one, and thus constitute a single circuit upon which are placed a number

page_text: of telephonic receivers T¹, T3 T³,... T¹, T₁, the number of which be
may very
large. While in the methods hitherto employed it has only been possible to use
four receivers to one transmitter, it is possible by this invention to operate fifty
telephones on a single circuit and by means of a single element of a Leclanché
battery.
According to another arrangement shown in Figure 2, the four transmitters with
their primary coils are placed in derived or branch circuits and are supplied by a
single battery. And according to the arrangement shown in Figure 3 the trans-
mitters and their primary coils are arranged in. series. The primary coils and the
secondary coils, each comprising an electro-motive force and a resistance, can be
grouped in a similar manner to the elements of a battery, according to any of the
arrangements adopted for the latter.
I connect all the departure wires of the transmitters in such a manner that they
operate as a single transmitter with a number of microphonic contacts. These
microphonic contacts are so arranged as to obtain the greatest amount of useful
work and the maximum yield, that is to say, generally in quantity; but in other
cases they are arranged in series, or both in quantity and in series.
The arrangement of the primary coils is also determined by the useful work. It'
is effected in quantity, in series, or both in quantity and series.
Figures 4, 5, and 6 represent examples of these arrangements. The primary
coils are withdrawn from the secondary coils for the sake of clearness.
The primary circuit is represented in Figures 4 and 5. The current coming.
from any suitable source S passes by the transmitters M' M². . . . M enters the
primary coils B¹ B². . . . B24 and returns to the source. In Figure 4 all the twenty
four primary coils are in derived or branch circuits; in Figure 5 two coils are in
series in twelve derived or branch circuits. All the transmitters are in derived or
branch circuits between the wires a, a, and b, b, so that they form in reality only
a single transmitter. The entering wires of the coils are connected by the wire b, b,
the departure wires by the wire c, c. The secondary circuit is represented in
Figure 6. The twenty four coils 61, 62, .... 621 are four in tension, in six derived
or branch circuits. The secondary current entering into the ninety six telephones
is divided into six derived or branch circuits, each of sixteen telephones in
series.
In arranging the coils, two theoretical views, which each indicate an opposite
grouping, should be considered. Theory would lead to arranging in series all the
secondary coils and all the telephones in order to obtain the greatest yield and a
maximum of useful work. But this arrangement cannot be employed because it
occasions the greatest loss (either for example by defective insulation, or by
absorption of the insulating medium, or by any other cause). In order to have a
*minimum of loss in this way; theory indicates the arrangement of the coils and
telephones in quantity. Practically a mean should be taken between the two. It
is necessary to group them in derived or branch circuits and in tension according
to the resistance and insulation of the cable. But to be able to group the coils in
a similar manner to ordinary batteries, it is indispensable that the phase of the
electric wave should be the same in all the coils. A trausverse wire should,
therefore, connect all the parts where the primary current coming from its source
enters into the group of coils; and a second wire should connect all the parts
where the current leaves the coils and enters the transmitters.
I
Having thus fully described the said invention as communicated to me by my
foreign Correspondent and the manner of performing the same I wish it understood
that I claim,
The improved method of augmenting or strengthening electric currents for
telephonic purposes, applicable for transmission to a number of receivers and to
great distances, and having the following essential and distinctive characteristics,
viz
First. The introduction of a number of secondary coils in the same telephonic
circuit to associate or combine the induced currents proceeding from a number of

page_text: microphonic transmitters and thus augment the electro-motive force and the
intensity of the current.
Second. The multiplication of the transmitters and their primary coils for
augmenting the variation of the microphonic current which generates the induced
currents in the secondary coils.
Third. The grouping, according to any known arrangements, of the secondary
coils and transmitters (each with its coil) in order to adapt their combination in
each case to the different applications for which they are required.
Fourth. The grouping of the coils in a similar manner to ordinary electric
batteries, and for this purpose the arrangements which permit of establishing the
harmony of the electric waves in the different coils," by introducing transverse
communications.
All substantially as above set forth and represented in the accompanying
drawing.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this thirtieth day of September in the year of our Lord
One thousand eight hundred and eighty two.