Year: 1886

page_text: We JOHN EDWARD DANN and JOHN LAPP of Honeoye Falls County of Monroe
and State of New York United States of America, Electricians, do hereby declare
the nature of this invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
The main object we have in view is to provide an improved speaking telephone
for use on long lines to which the instruments in general use are not applicable.
Our system includes transmitting,, receiving, and anti-induction apparatus con-
structed, combined, and operating as hereinafter described. We will proceed to
describe them in detail, in the order named, and by reference to the accompanying
four sheets of drawings.
Our transmitter is an improvement in the class of instruments having vibrating
electrodes arranged adjacent to, and one of them normally pressing upon, the
diaphragm and in some cases attached to it. The object we aim at; and have
attained is the production of a loud-speaking instrument capable of operating with
a minimum expenditure of battery power, or electro motive force. To this end we
have devised a new and improved construction of the diaphragm and also provided
an improved mechanism for co-operating therewith, as hereinafter fully described.
In accompanying, drawings Sheet 1, Figure 1 is a perspective view of the
mechanism of the instrument, Figure 2) is a vertical cross-section, Figure 3 is a
side view. Figure 3 is a cross section of a modified form of one of the electrodes.
Figure 3b is a similar view showing this: form combined with a carbon electrode.
Figures 4 and 5 are modifications. Figure 6 illustrates a defective operation of
the diaphragm of other transmitters.
.
:
The sheet metal diaphragm A is constructed with a central conical portion a
which may be formed integral therewith, or made separately and attached by
solder, brazing, or in any, other suitable manner. The diameter of the base of the
hollow cone may be varied considerably, but we prefer it shall equal, or even
slightly exceed, that of the contiguous inner end of the mouth-piece B of which it
forms practically a conical extension. By this construction and combination of
parts, the whole force of the air current or sound waves from the mouth of the
person speaking into the instrument is concentrated on the cone, that is to say,. on

page_text: the central portion of the diaphragm thereby producing the maximum effect in
respect to the required vibration of the latter, and the transmission of sound with
corresponding loudness, force, and precision. A lever C, which constitutes one of
the electrodes, is permanently attached to the apex of the cone a through the
intermediary of a spring, or other device which will allow the lever to vibrate &
within certain narrow limits. The lever may, however, be rigidly attached to the
cone, and in that case, of course, the diaphragm must yield enough to permit due
vibration of the lever. The fulcrum of the latter is a spring, or flexible plate d
which is held adjustably by a clamp e to a fixed bar D supported by posts f.
A shorter lever C, is arranged parallel to, and in front of, the former (C), and also 1
attached to its middle portion by a short spring g, which constitutes a yielding
fulcrum that permits slight movement of such shorter lever toward and from the
other. The outer or free end of this lever C¹ has an eye or socket that holds the
other electrode, to wit, a short metallic pin E. The latter is suitably insulated in.
the socket by rubber or equivalent means. The inner end of the pin E rests,
normally, in light contact with the free end of lever C, and it is the vibration of
these two parts C and E, corresponding exactly to the vibrations of the diaphragm,
that effects the transmission of speech. The electrodes must act with perfect
freedom in order to attain the required rapidity of vibration essential to trans-
mission of a certain rapid succession of sound waves, but heretofore such action
has not been practicable owing to undue adhesion or "stick" of the electrodes at
the instant of variation or interruption of the line current corresponding to the
vibrations of the diaphragm of the transmitter. We have conducted experiments
with the purpose of discovering a reliable method or means for neutralizing such
adhesive force, and have found an improved result could be attained by use of a
local circuit, acting through the electrodes reversely to the main circuit; and we
have also become satisfied that an analogous, although a greater, effect could be
attained by constructing the electrodes of different metals or other substances
which are non-attractive, or mutually repellant. In the course of our experiments
we have discovered that carbon has a repellant quality which is practically available
for overcoming the aforesaid "stick" and hence its employment in a make-and-
break transmitter is very advantageous. It constitutes therefore our preferred
means for the purpose indicated. To indicate more particularly the quality of
carbon referred to, we will state that when a current is sent through a freely
suspended carbon electrode it will separate slightly from the opposite electrode,
and stand thus repelled so long as the current remains unchanged. We insert a
piece of carbon in the outer or free end of the lever C, Figure 2, so that the
metallic electrode E rests in contact therewith instead of with the lever proper.
At the instant of interruption of the current the carbon repels the other electrode.
By this means, rapidity of separation and vibration of the electrodes is efficiently
promoted and the instrument thereby adapted to transmit speech with greater
fidelity and speed.
By another method, which we have found to work well, we utilize the well
known principle, that certain metals, notably iron, become expanded when under
the influence of an electrical current. We have therefore provided one of the
electrodes with a portion which is expanded when the circuit is closed but retracts
more or less when such current is broken or lessened in strength, and thus aids
mechanically in operating the electrodes.
Referring to Figure 3ª of drawings (Sheet 1.) a indicates a thin plate of iron, or
equivalent material, which constitutes part of an electrode. Said plate is secured
in a holder b made of brass or other metal not subject to appreciable expansion
under electrical influence. The holder b has a circular recess and is provided with
an internal shoulder or rabbet. The diaphragmn a fits snugly within the rim of the
holder and rests on said shoulder as shown. It is essential that the edge of the
diaphragm shall be confined either by close frictional contact with said rim, or by
solder or other equivalent means, since the desired action of the larger electrode

page_text: depends mainly on the expansion of the central portion of the diaphragm as will
be now explained. It is well known owing to some form of molecular change a
bar of iron, when traversed by an electrical current, becomes somewhat elongated.
It is therefore apparent that if a current be sent through the diaphragm of
electrode B it would normally become enlarged, that is to say, expanded radially;
but such expansion being prevented by the rigid rim of holder b a compensating
change of form is produced, in that the diaphragm is projected outward or bulged
into convex shape as shown, exaggerated, in Figure 3ª.
In Figure 3b (Sheet 1) we illustrate the use of the carbon electrode with the one
having a portion that is expansible as before described. By this combination we
attain the greatest rapidity of separation of the electrodes since each repels the
other when the current is interrupted.
Referring again to Figures 1. 2 and 3, the pin electrode C¹ is supported and
adjusted and also connected with a lever G by means of a spiral spring F. Said
lever is arranged parallel with the fixed bar D and attached to it by a flexible
fulcrum piece h provided with a screw i at its opposite or free end for adjusting it
closer to, or farther from the bar D. A screw clamp secures the spring F to the
lever and it is suitably insulated by a rubber block. In practice, the diaphragm A
and spring F are connected by wires xy with the primary of an induction coil
and with a battery neither of which is shown in the drawings; or the instrument
may be set in a battery circuit with an intensity coil properly connected with the
line wire. When a sound wave strikes upon the diaphragm, its main force is
concentrated at the centre which is capable of the greatest amplitude of vibration,
and the consequent movement of the diaphragm is transmitted to the electrode
lever C so that the free end of the latter vibrates with a greater amplitude than
the diaphragm owing to the fulcrum & being nearer the end attached to the cone a.
This vibration of the lever electrode C effects an instant separation from the pin
electrode E and consequently produces a series of electrical impulses of the line
current thereby effecting the transmission of sound through the receiving instru-
ment at the other end of the line. In addition to the function of the cone a in
concentrating the sound waves as above stated it has a still more important one
which we will explain as follows;-When a sound wave strikes upon a diaphragm
of the usual form with whose centre an electrode rests in contact, the latter resists
more or less the tendency of such central portion to yield and assume a concavo-
convex form, and consequently the portion surrounding the centre yields first,
as illustrated in an exaggerated way in Figure 6, in which A¹ indicates the
diaphragm and C an electrode. The result is a failure to transmit and reproduce
sound with the desired loudness and accuracy. But by the use of the cone a this
defect is avoided since the air wave pressure forces back the cone or central portion
of the diaphragm before, or else simultaneously with the portion that surrounds it.
In other words the diaphragm vibrates with the freedom and in the manner
required to produce in connection with the other mechanism employed the desired
perfection of result.
A still further advantage attends the use of the cone since it is capable of with..
standing the pressure and thrust to which it is subject in acting on the attached
lever, and hence the diaphragm is made correspondingly more durable than if
constructed in the usual form. In further relation to the cone a we desire it to be
understood that while it is desirable, and even necessary, that its inner side shall
be open, as shown, in order to produce the best result, yet we do not propose to
here limit ourselves to such construction, since a good degree of success may be
attained by closing the base of the cone, that is to say, by employing a diaphragm
of the ordinary form and attaching a hollow cone to its centre. Our improved
diaphragm is applicable to other telephonic instruments besides transmitters.
In respect to adjustments it may be stated that the spring fulcrum d of the inner
lever electrode C is properly adjusted when the apparatus is prepared or "set up
for use.
The lever G is adjusted by screw i to increase or lessen the tension of the

page_text: spring F and thereby regulate the contact pressure between the electrodes (E. C.) as
required for the desired perfection of operation. If in practical operation of the
instrument a metallic sound arises from the molecular or mechanical vibration of
movable parts, particularly the electrode levers and the spring F, it may be quickly
destroyed by elastic bands stretched between suitable points of attachment and
pressing lightly on the spring F and pin electrode E and both levers C and C¹. We
do not propose to limit our Invention to the above described and preferred
arrangement of levers shown since various others are practicable. As an example
the outer electrode might be attached to the lower end of a metal strip or bar C¹ as
shown in Figure 4 and said bar may be a spring, or it may be inelastic and in the
latter case the action of gravity would be depended on to hold it in light contact
with the other electrode C.
Figure 5 illustrates still another arrangement wherein both levers C C¹ are
attached to the cone, which thus acts directly on both when vibrated so that the
electrodes are separated positively and quickly. In brief, under any arrangement
that we contemplate as most desirable, the operation is the same namely the first
vibration of the diaphragm due to impact of a sound wave breaks contact between
the electrodes and thus the action is positive and instantaneous rather than indirect
or secondary and delayed as is the case when electrodes are employed that are
unattached to the diaphragm but suspended to vibrate independently and hence do
not separate on the first movement of the diaphragm but on its return movement.
It is also expedient to employ dampers or elastic pressure plates as shown in the
drawings to limit the vibration of the diaphragm and thus choke out the metallic
clang. When the electrodes are attached to rings we employ mechanism for
adjusting the tension of the latter and thereby regulating the pressure of the
electrodes on each other and on the diaphragm so that the instrument can be made
duly sensitive to sound waves.
In Sheet 2 of the drawings-Figure 1 is a perspective view of the adjusting
apparatus applied to the door of a transmitter box. Figure 2 is a central vertical
transverse section. Figure 3 represents a modification of a certain part of the
apparatus.
The springs E and F carry the small and large electrodes C and D respectively.
The springs are so adjusted as to hold the electrodes in easy contact with each
other and the diaphragm. The spring E is electrically connected by wire x with
one pole of a battery, and the spring F with the primary wire y of an induction
coil that is connected with the other pole of said battery in the usual way. The
plate b is secured adjustably parallel, or nearly so, to the door of the box by three
screws c which pass through it near the corners, and enter the plate a. The
electrode springs E. F being attached to the lower end of this plate b it is apparent
that by turning the screws c in or out, said plate and springs will be moved
correspondingly in one direction or the other, so as to vary the pressure of, the
springs as required. To obviate any danger of want of rigidity of the plate in the
position to which it may be adjusted we employ the pressure device consisting of
the screw d, nut f, and spring f¹. This screw is fixed in the fixed plate a and
passes loosely through the movable plate b. Between the latter and the nut the
spiral spring encircles it as shown. Hence, by adjusting the nut, the spring fis
caused to press more or less tightly on the plate so as to take any slack due to want
of perfect fit between the screws and the threaded holes in plate The spring E is
insulated by blocks g of soft rubber or equivalent non-conducting material and
secured by a rubber clamping piece h having narrow slots to receive clamping
screws . A third screw passes through the metal plate and bears against the
upper end of said piece. By turning it the latter is adjusted relatively to plate b
and thus the spring E is thrown one way or the other and its pressure changed as
required independently of the spring F of the other electrode.
In Figure 3 we show a modification of the smaller electrode, the same consisting
of a spring having a series of arms and a series of pointed electrodes affixed to

page_text: them. This device may be used in case it is required to increase the amount of
current thrown on the line.
For the best result our transmitter requires to be used with a receiving instru-
ment whose diaphragm is held under strong magnetic tension as hereinafter
described. And further we have found that in order that the interruption of the
line current due to action of the transmitter shall affect the diaphragm of the
receiver as powerfully as possible, it is necessary to employ a positive means of
connection between said diaphragm and electro-magnets which are placed adjacent
thereto and arranged in the line circuit. Thus, we employ two horse-shoe electric
magnets arranged opposite each other i.e. respectively right and left from the
diaphragm and on the rear side of the same; and we connect both armatures of
said magnets with the diaphragm by rigid rods so that both shall simultaneously
act on the latter to vibrate it as forcibly as possible. We have found by experi-
ment that this arrangement produces a very marked effect in loudness of tone and
a better one than can be secured by employing a single magnet of double the size
of one of ours. The improvement is doubtless attributable mainly to this cause,
namely the + and - poles of each magnet react on each other and intensify their
respective polarities; and the same is true of the polarities induced in each armature,
so that the force of the current is converted into a strong magnetic attraction that
acts powerfully on the diaphragm. Some importance may also be attached to the
effect of two armatures acting at once, since they mechanically neutralize each other
in so far as they would tend if acting separately to distort the diaphragm by
reason of moving in an arc and not in a plane at right angles to the same.
In Sheet 3-Figure 1 is a perspective view of our receiving instrument, the back
or cover being detached. Figure 2 is a rear elevation of the same the arma-
tures being removed. Figure 3 is a cross-section through line xx Figure 1.
Figure 4 is a vertical section through line y y Figure 1. The letter A indicates the
body of the receiving instrument. The diaphragm B is arranged as usual in
telephonic receivers, and may be made of metal, membrane, or other suitable
material.
Laterally from the diaphragm are arranged two horse-shoe magnets C C one on
each side, their feet pointing backward. The flat bar armatures D D of said
magnets have rigid horizontal arms a which project toward each other so that their
free ends nearly meet at a point directly opposite the centre of the diaphragm B
with which they are connected by means of small but rigid rods E. The latter are,
in this instance soldered to the diaphragm, it being of metal, but when made of
membrane it is obvious that some other suitable means of connection will be
necessary. Short rigid arms bb also project backward from the armatures D D and
have points è that rest in sockets in the heads of screws d. The latter serve as
adjustable bearings or supports for the armatures by which their proximity to the
magnets (which they are never in actual connection with) may be easily regulated
at will. In place of these screws various devices for supporting and holding the
ends of arms b b may be employed. It will be seen that the armatures have thus
two points of support; namely the diaphragm and the screws, but they are held
attracted by the magnets whose cores are polarized so that the diaphragm is thereby
pressed outward or held under tension to a degree corresponding to the constant
attractive force of the magnets. In place of the latter being of the permanent type
we may employ soft iron cores energized by a local circuit. But the former
arrangement is the more economical. To supplement the action of the polarized
magnet cores on the armatures and to better hold the latter in due position, the
armatures are provided with plate-springs f extending rearward and whose free
ends are held under a pivoted catch g or other suitable device. It will be noted
that the point of contact of such springs and catches is in alignment both ways
with the heads of screws d which local relation is essential to vibration of the
armatures with the least friction and greatest freedom and accuracy The con-
nection with the line wire is from binding post 1 to the centre of the coil around

page_text: the adjacent leg of the nearer magnet and from the outer coil of such leg to the
centre of the coil on the other leg, thence to the opposite magnet and then to the
other binding post 2. It will be apparent from this arrangement that both magnets
are energized simultaneously by the line current and simultaneously demagnetized
when the circuit is broken (save of course the constant attraction proceeding from
polarized cores) Both armatures are therefore attracted and released at the same
instant so that their push rods E act together on the diaphragm B throwing it into
vibrations corresponding to the impulses or interruption of the current, and effecting
the transmission of speech loudly and accurately.
It is well known that if two electrical conductors be placed side by side in a
certain proximity to each other a current sent through one of them will induce
a current in the other which will be strong or weak according to the distance
between said lines and the strength of the primary current. This effect is
particularly objectionable in telephonic circuits since it not only destroys privacy of
communication through adjacent wires but, what is still more important in our
system it greatly retards transmission which is often equivalent to preventing it
altogether in long circuits. We have therefore devised an improved means for
preventing such inductive disturbance and thereby enabling messages to be
transmitted with entire privacy and over lines of unusual length. The device we
employ is exceedingly simple and inexpensive and adapted for application to a
line wire at any point where required and serves to remove the surplus electricity
that would otherwise be diverted to an adjacent wire and thus induce a current
therein It therefore operates as an electrical safety inductive discharge to prevent
objectionable double transmission of messages.
In Sheet 4-Figure 1 is a partly sectional view illustrating the general con-
struction of our device and its application to a line wire. Figure 2 is a cross
section of the device and line wire. Figure 3 is a perspective view of the hood
for protecting the earth wire. Figure 4 illustrates a modification of the hood.
Figure 5 is a sectional view showing a detail Figures 6. and 7. are perspective
views of modifications.
Referring in the first instance to Figures 1 and 2 the letter A indicates a
telephonic line wire and B the device we employ for taking off the surplus electricity
that would otherwise cause an inductive disturbance in a neighboring wire (not
shown). Said device is composed of a cylinder a of copper or other good conducting
material which is insulated or held out of contact with the wire A by means of an
interposed tube b6 of rubber, and connected with the earth by the metal strip or
wire C. Another rubber tube c surrounds and encloses the copper cylinder and
protects it from exposure to the atmosphere or to moisture. In practice we prefer
to make the copper cylinder shorter than the rubber tube b, and the outer tube c
longer than the latter, so that its ends may be clamped tightly around and on the
wire A as shown in Figure 5, so as to effectually exclude moisture. It is important
that moisture shall also be prevented from access to the earth wire C for a portion
of its length To this end we enclose its upper portion (see Figure 1) in a rubber
sheath d, which is cemented or otherwise suitably connected to a rubber tube c so
as to form a water tight joint between them. To the adjacent post D or other
fixed object, we attach a sort of hood E (Figures 1 and 3) which is made of any
suitable material. In the open mouth or upper end of this hood a cork e is
inserted and the earth wire C passes through it and the body of the hood, while
the sheathing d is drawn over both the cork and neck of the hood and secured
tightly around the latter. In this manner all danger of accumulation of ice
sufficient to form an earth-conductor is entirely obviated.
In Figure 4 we illustrate a modification of the hood, the same E¹ being open at
the bottom only and the earth wire C being passed up underneath and secured to a
support projecting from the post.
It will be seen that in Figure 2 we have represented the copper and rubber
tubes as divided or slotted lengthwise. This construction we propose to employ

page_text: "when convenience may suggest it in applying our device to line-wires already
suspended, since the slit allows the tubes to be slipped over the wire and each
other without necessitating dividing or disconnecting it at any point. But,
ordinarily, in applying the device to new wires it will be more expedient to attach
it when the same are being erected and for convenience it may be furnished already
attached to a section of wire suitable to be embodied in and form part of the long
wire proper.
In operation the copper cylinder a takes up such surplus electricity as would
otherwise induce an objectionable disturbance in the neighboring line and conducts
it to the earth so that the message sent cannot be received or heard by any one
save the person at the receiving instrument.
The modification shown in Figure 6 consists of two copper or other metal
plates at a one of which a¹ is inserted in and forms virtually part of the line, and
the other a² is placed alongside and supported by any suitable means.
This second
plate a like the cylinder a before described discharges the surplus electricity by
the principle of induction on the line plate a¹.
In Figure 7 we show a metal cylinder f to which the line wire A is attached.
Within it we place a copper cylinder a and surround it with a rubber tube c that
effectually insulates it from the outer metal tube f.
In respect to the diaphragm of the transmitting instrument we will state that
we are aware a diaphragm having a conical portion with a surrounding annular
part which is curved transversely (or in cross-section) has been suggested or
employed and we therefore restrict our claim to the precise construction of our
diaphragm which experiment has demonstrated to be advantageous. Nor do we
claim broadly the use of carbon to form an electrode of a transmitter since we are
well aware of its extensive use for that pupose but, so far as we have been able to
ascertain, we are the first to practically apply the principle of repulsion of carbon
in a make-and-break Telephone that is to say-a telephone in which the current is
interrupted and the electrodes are separated in the act of transmitting; and we are
hence the first to utilize such repulsive action in overcoming the "stick" between
the electrodes which has been a great obstacle to practical efficiency of such
instruments.
Having now particularly described and ascertained the nature of the said
Invention; and in what manner the same is to be performed; we declare that
what we claim is ;-
1. The method of neutralizing the undue tendency of the electrodes of a
telephonic transmitter to adhere, at the instant of variation or interruption of the
line current, by means of an opposing force due to electrical action applied through
one or both of said electrodes.
2. In a make-and-break telephone, the employment of carbon to form one or
both of the vibrating electrodes, for the purpose of aiding in separation of said
electrodes, by the repulsive action of carbon, as specified.
3. The method, substantially as described, of neutralizing the tendency of the
contact electrodes of a telephonic transmitter to unduly adhere at the instant of
variation or interruption of the current, by producing a molecular change in the
electrode which is metallic, and thus effecting its expansion.
4. In a telephone of the character hereinbefore specified, the combination with
the diaphragm and a movable or vibrating electrode, of another movable lever
electrode having a carbon contact. point, the parts being arranged substantially.
as specified, whereby the "stick between the electrodes is overcome and they
are adapted to separate instantly when the diaphragm vibrates, as hereinbefore
specified.
"
5. In a telephone of the character hereinbefore specified, the combination with
the diaphragmn and an electrode E, of the lever C connected with the diaphragm;

page_text: and carrying a carbon contact point which is separated from the other and thus
interrupts the current, as specified.
6. The combination with the diaphragm and the longer electrode C attached
thereto, and the spring fulcrum ḍ therefor, of the electrode C¹ and its spring
fulcrum, substantially as shown and described.
7. The combination with the diaphragm and the vibrating lever electrode C
attached thereto, and having a spring fulcrum, of the second electrode lever C¹ and
a spring fulcrum therefor which connects it with the other (C) at a point between
the fulcrum and free end of the latter (C) as shown and described.
8. The combination with the diaphragm, the electrode levers the spring F, and
a fixed bar D, of the adjustable lever G, and the screw i, all arranged as shown
and described to operate as specified.
9. The diaphragm having a central hollow cone, and an adjoining, surrounding,
annular, part which is flat, or in the same plane, and is wholly free to vibrate, as
shown and described.
10. The combination with the diaphragm and its central hollow cone, of
electrode levers having yielding fulera, and one of them attached to said cone,
substantially as shown and described, to operate as specified.
11. The combination of the spring F, with the connected electrode levers, the
spring or elastic fulcra therefor, and the diaphragm having a hollow cone to which
one of said levers is attached, by a yielding connection, all as shown and described.
12. In a telephone of the character hereinbefore specified, the combination with
the diaphragm, of electrodes C. D, and springs carrying the same and arranged
pendent parallel, or nearly so, to said diaphragm, all as shown and described.
13. In a telephone of the character hereinbefore specified, the combination with
the diaphragm and spring carrying electrodes, of the movable plate to which said
electrodes are attached, and screws for supporting and adjusting said plate, as
shown and described.
14. In a telephone of the character hereinbefore specified, the combination with
the movable plate to which the electrodes are attached, and screws for adjusting it
as specified, of the clamping device consisting of a screw, the nut and spring
arranged as shown and described.
15. In a telephone of the character hereinbefore specified, the combination with
the diaphragm, the electrode C, and spring E, of an insulating block, a clamping
plate h, and screws i for securing and adjusting the latter, as shown and described
for the purpose specified.
16. In the telephonic receiver, the combination with the diaphragm B of the
two horse-shoe electro magnets C and C arranged on the rear side of, and in
laterally opposite directions from, the diaphragm; the two armatures D D having
arms a projecting toward each other; and the two rigid rods E E connecting these
arms with the centre of the diaphragm, as shown and described for the purpose
specified.
17. In a telephone of the character hereinbefore specified, the combination of
the socket screws with the armature arms having points, that constitute bearings
or fulcra for said armatures, as shown and described.
18. As a means for preventing inductive disturbances in telephonic lines, a
conductor placed contiguous to, but separated from, the line wire, and having an
earth connection whereby said conductor is adapted to operate as specified.
19. The combination with the line wire of a metal inductor, means for insulating
it, and an earth wire attached thereto, as shown and described.
20. An inductive device for the use specified, the same being formed of the
metal cylinder, a rubber insulator or tube, and an earth wire, as shown and
described.
21. The improved inductive device formed of the interior and exterior rubber
tubes, the interposed copper cylinder, and the earth wire attached to the latter,
and having an insulating protective sheathing, as shown and described.

page_text: 22. The inductive discharge device consisting of a conducting cylinder and
insulating tube having lengthwise slits, as shown and described, for the purpose
specified.
23. The combination of the inner rubber tube b, the copper cylinder a, and the
outer rubber tube which is made longer than the others to adapt it to be tied
over them and around the line wire, as shown and described.
24. The combination with the line wire and an inductive device, of a hollow
device adapted for attachment to a post or other fixed object, and the earth wire
which passes through it, and is thereby protected from moisture at that point, all
as shown and described.
25. The combination with the line wire and an inductive device attached
thereto, of the earth wire, and the hood having an open mouth, and a sheathing
applied to it, and the said earth wire, as shown and described.
Dated this 23rd day of March 1886,
J. E. DANN.
JOHN LAPP.
By A. M. & W™ Clark, Agents