IMPROVEMENTS IN ELECTRO-MAGNETIC ANNUNCIATORS
Year: 1874

page_text: LETTERS PATENT to Louis Finger, of Boston, in the County of
Suffolk, and State of Massachusetts, of the United States of
America, for the Invention of "IMPROVEMENTS IN ELECTRO-MAGNETIC
ANNUNCIATORS."
COMPLETE SPECIFICATION filed by the said Louis Finger at the Office
of the Commissioners of Patents, with his Petition and Declaration,
on the 23rd January 1874, pursuant to the 9th Section of the
Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
FINGER, of Boston, in the County of Suffolk, and State of Massachusetts,
of the United States of America, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
ELECTRO-MAGNETIC ANNUNCIATORS," and have petitioned Her most Excellent
Majesty Queen Victoria to grant unto me, my executors, administrators,
and assigns, Her Royal Letters Patent for the same, and have made
solemn Declaration that I am the first and true Inventor thereof.

page_text: of mechanical devices to be herein-after duly explained are operated so
as to strike a bell, and partly revolve a cylinder or drum arranged on its
periphery with blanks, names, and numbers, as will be duly explained,
to the proper distance required to bring to view the number of the room,
and the name of the article or person wanted. The plane or lever being
released after the passage of the ball or other body, which is finally
deposited in a receptacle prepared to receive it, and the electrical circuit
opened, leaving the cylinder or drum in the position desired until turned
back to its original position by the operation of a series of mechanical
devices that will be more fully described in due course.
A modification of this first portion of my Invention consists in a series
of stationary inclined planes arranged at opposite angles in a frame,
provided with apertures opening on to the upper ends of each plane, and
having a metallic spring attached at one end of and a metallic stem or
pin connected with the side of the interior of the frame, the stem or pin
and spring being suitably connected with the opposite wires of an
electrical battery, and with the other portion of the annunciator, so that
a ball or other body descending from one plane to the other presses the
spring against the pin or stem and closes an electrical circuit, by which
the cylinder or drum of the annunciator is operated in the same manner
as by the former arrangement.
In Figures 1, 2, 3, 4, and 5 of the Drawings a represents the bottom,
and a¹ the face of the case of one portion of my improved annunciator,
which is provided on the front with an aperture 6¹, and to the interior of
which is attached by a standard c or otherwise a frame consisting of two
longitudinal plates d, d', connected by rods or bars e, e¹, and supporting
in the centre near the top the ends of a shaft f carrying a ratchet
wheel g, with which engages the teeth of a ratchet sector o formed with
a lever arm o¹, connected with a shaft / supported by the sides d, d¹.
Attached to one end of the shaft h is a vertical arm i that is pivoted at
the bottom to and operated by a horizontal leverk that extends through
the face of the annunciator, and is provided with a cap or knob 7. The
ratchet wheel g is attached to or formed on the outside of a geer wheel m,
the teeth of which engage with a pinion n connected with a shaft p that
is supported in the sides d, d¹, near the rear of the frame, and which
revolves a cam or escape wheel q, formed with two or any desired
number of projections q¹ that are held or released by a curved arm of
4 bell-crank lever connected with a rod 8, the ends of which turn in and

page_text: are supported by the sides d, d'. The vertical portion of the lever r
extends downward and connects with an armature t arranged horizontally
opposite the ends of an electro-magnet u, u³, situated at the bottom of
the frame d, d³, and supported at the other end by a bar connected
with the bar or rod e. The magnet u, u³, is supplied with wires, one of
which w connects with an electrical battery, and the other with a caller
or other portion of the annunciator, or the wire w may connect with the
caller, and the wire w¹ with the battery. Attached to the bar or rod e¹
is a bent arm x, in the lower portion of which is a screw y operated by
a thumbscrew and binding washer y¹, so as to press against and be
released from the arm r³, and properly adjust the arm in relation to
the cam or escape wheel q. Connected with the bottom of the armature
lever r, and bearing on the top of the bent arm x is a spring L, for the
purpose of bringing the armature arm in position after its release from
the cam q. Connected with the shaft f, between the geer wheel mand
the frame d is a rubber, ivory, or other insulated wheel or disk a", in the
periphery of which is inserted a piece of metal 6", that connects by a
wire with an electro-magnet du supported on the interior of the case,
and whose armature e" is formed by the lower horizontal portion of a
bent rod or arm g¹ that passes through the face a¹, and operates a
hammer h¹ connected with its other end against a bell or gong, etc. i,
attached to the outside of the case over the aperture 6¹, or situated in
any other desired position. The armature e¹ is kept in proper position
by a spring ¹ held at one end by a pin l, the other end bearing against
the bottom of the armature e", the top of which is prevented from
running beyond its desired point by a pin m¹ situated over it, or the
armature may be regulated by any other method that may be desired.
Bearing on the top of the wheel or disk a¹¹ is a metallic spring o¹ that
connects by a wire c¹¹ with the caller wire. Connected with the side d¹³
on the inside is a stem n¹ that holds one end of a bent spring p³, the
other end of which bears on the top of a pin or stem q" attached to the
side of the ratchet sector o, so as to press the sector down and operate
the shaft f, and turn the wheels g, m, and a", and cylinder P in a
forward direction, and revolve the cam q in the opposite direction.
The other feature of the first portion of my improved annunciator is
designated the caller, the face of its frame being represented in the
Drawing by the letter A, and its sides by B, B¹. The face A is formed
with apertures C arranged alternately one above the other on each side,

page_text: and just above the opposite ends of inclined levers or planes D arranged
at opposite angles with each other, and provided on the bottom near the
lower ends with a metallic plate E formed with a socket to receive a
pivot attached to the face of the frame, and on which the inclined lever
or plane turns, and connected with which is a metallic disk G connecting
by a wire w¹ with the annunciator or other portion of the apparatus, or
with the battery.
Attached to the interior of the face A are right angled standards H
situated forward of plates E nearer the lower ends of the levers or
planes D, and extending horizontally at the top under the bottom of the
levers or planes D, which are provided just above the horizontal portions
of the standards H with metallic stems or points I connected with the
wire wo¹, communicating with the other portions of the annunciator or
with the battery.
Connected with the standards H is a wire to that communicates with
the battery or with the annunciator, according as the wire of the stem I
is connected, the stems and standards being made to connect with
opposite wires. The bottoms of the upper ends of the levers or
planes D rest when at case on blocks R attached to the interior of the
sides B, B¹.
At the bottom of the interior of the frame A are two stationary
inclined planes D" joined at the centre, and sloping inwards towards the
front so as to conduct a ball or other suitable body O that operates down
the inclined levers or planes D, as will be duly explained through h,
bottom aperture C³, into a cup or receptacle M arranged on the outside
of the face A to receive and hold the ball or other body O when not in
use. The apertures C are suitably lettered or otherwise designated to
indicate the articles or persons desired, and are provided on the outside
with projecting cups or receptacles M, in any one of which corresponding
to the want required the ball or other body O is deposited.
Connected with and revolved by the shaft f and extending over the
frame d, d, (Figures 1 and 2) is a cylinder or drum P (Figures 1 and 3).
arranged on the periphery in two parallel rows or spaces P¹, P", the
spaces of one row P¹ consisting of a blank and numbers corresponding to
the number of the room connecting with the annunciator, and the
spaces P" of the opposite parallel row containing a blank and the names

page_text: •
apertures C.
The operation of this first portion of my Invention is as follows:-The
annunciator, or that portion of my Invention represented by Figures 1,
2, and 3, is placed in the servant's hall, offices, or in any other place
convenient to the attendant, and the "caller," or that portion of the
Invention represented by Figures 4 and 5, is placed in any apartment
or place from which an order is to be given. The wires w, w¹, of the
magnet u, u¹, connect respectively with an electrical battery and with
the "caller," whose other wire communicates with the opposite wire of
the battery, so that when an order is given the ball or other body O is
taken from the receptacle C¹ and placed in the desired receptacle C,
against which the required want is indicated, and from which it passes
through its corresponding aperture and descends the inclined lever or
plane D adjacent to the aperture, and as it passes the fulcrum of the
lever tips by its weight the pivoted end of the lever or plane so as
to bring the metallic pin or stem I and its wire w¹ in contact with the
horizontal portion of the standard H, and its wire w and close the
electrical circuit, thereby causing the armature t to be attracted to the
magnet u, u', thus operating the armature lever r so as to free the cam
or escape wheel q, which makes a half revolution or as many partial
revolutions as the cam is formed to allow, and permits the geer wheel m
to be revolved by the downward action of the ratchet sector o induced
by the pressure of the spring p¹ on the stem or pin q", a distance
determined by the number of the teeth or spokes of the pinion n
connected with the shaft p that operates the cam or escape wheel 9, and
the number of the teeth of the geer and ratchet wheels m and 9. Thus
if the pinion n has eight teeth and the geer wheel m fixty-six the geer
wheel m and consequently the cylinder or drum P operated by the same
shaft will revolve one-fourteenth of its circumference. If a greater or
less number than fourteen partial revolutions are desired the train must
be arranged accordingly, that is, if thirty partial revolutions are required
the escape wheel q may be made with three projections, the pinion with
nine teeth and the geer with ninety teeth. Thus the number of partial
revolutions may be increased or diminished by increasing or diminishing
teeth of the train and the projections of the cam or escape wheel.
The ball or body O as it passes from one lever or plane to the other
releases the lever or plane, and disconnects the wires u, u³, of the plate H

page_text: •
and stem I, and opens the circuit, thus leaving the cylinder at rest until
the circuit is again closed by the passage of the ball or body O over the
fulcrum of the next lever. Thus it will be seen that the cylinder P is
partially revolved each time the ball passes down a lever or plane, so
that if the ball be put through the lowest aperture C it will descend
only one lever, and consequently the cylinder P, which is set at blank,
will be partially revolved once, thereby bringing into view through the
aperture 6¹ the number of the room from which the order is given, and
the name of the article or person corresponding to the name of the
article or person set against the aperture C, through which the ball or
body is inserted. If the ball, etc., is deposited in the aperture C next
above the bottom one it will descend two levers or planes, and con-
sequently cause two partial revolutions of the cylinder P, and bring into
view the number of the room and the name of the article, etc., corre-
sponding to that set against that aperture, and so on, as many levers or
planes may be arranged, apertures formed, and articles or persons
indicated as there are partial revolutions provided for the cylinder.
When the ball or body has passed the requisite number of levers or
planes, and the cylinders has been turned the required number of times
to indicate the article desired, it descends the inclined plane D" and
is directed by the lateral incline of the planes into the bottom
receptacle M¹, and the cylinder P remains at rest until the order has
been attended to, when the attendant by pushing in the lever k that
actuates the arm a¹, so as to turn the shaft h and operate the ratchet
sector o, which revolves the train in an opposite direction and sets the
cylinder P back to its original position, that is, so that the parallel
blank spaces will be shown through the aperture 6².
From whatever room or place the order is given, or whatever the
order may be, the bell or gong, etc., ¹ is immediately struck by the action
of the first lever operated, which brings in contact the wires u, u¹, of
the caller, one of which communicates with the metallic spring c¹
connected with the battery or the magnet d", and bearing on the
insulated disk a", which when revolved by the shaft f brings the.
metallic piece 6", connected with the magnet du or the battery, in
contact with the spring c¹, thus closing the electrical circuit and causing
the armature e to be attached to the magnet du, thereby operating
the hammer against the gong, etc., i,

page_text: In the modification of my Invention the inclined planes D' of the
caller are permanently attached to the face A, one above the other, at
opposite inclinations; and a metallic spring Q is attached at one end
to the side of the frame opposite the lower ends of the inclined planes,
so that the ball O or other body in passing from one plane to the other
comes in contact with the spring Q .connected with one of the
wires u, u, and presses it against a metallic pin or stem T attached to
the side of the frame and connected with the opposite one of the wires
w, wo, thus bringing the wire of the spring Q in communication with
the wire of the stem T and closing the circuit, which is opened by the
release of the spring Q by the fall of the ball on to the lower plano,
and thereby operating the cylinder P and bell, etc., in the manner
herein-above described.
Instead of arranging the caller with apertures and receptacles, as
hercin-above described, it may be arranged to allow of the descent and
return of the ball; and the lever or plane, or each section thereof, may
be supplied with a ball or other body, restrained and released by sliding
valves or plates, etc., or turning flaps or plates, operated from the
outside by levers arranged to shove in and out of the frame, or by
thumbscrews and stems, arranged to turn the flaps or plates up or
down, or by any suitable arrangement of devices that may be preferred
for holding and releasing the ball, etc. The inclined levers or planes D
instead of turning on a pivot, as shown and described, may be hinged
or connected with a spring at one end, or arranged in any other desired
manner, to allow the stem or pin I to be brought in contact with and
released from the top of the standard H. The levers or planes D may
be pivoted and the standards H may be situated near the upper ends
of the levers, so that the standard H and stem I may be brought in
contact and an electrical current produced as soon as the ball touchics
the upper end of the lever.
The second portion of these improvements consist in a method of
operating the character card or shield, as will be duly explained, by which
the act of summoning a servant or calling for any article is greatly
simplified and rendered more certain.
"
The Drawings represent in Figure 6 a front view, in Figure 7 an
end view, and in Figure 8 a horizontal section of an apparatus
embodying the second portion of my improvememts; Figure 9 is a
plan, and Figure 10 an elevation of the armature and its mechanism;

page_text: while Figure 11 is a section of the character card or shield; and
Figure 12 is a view of a device for detecting fire, which I have combined
with the annunciator.
In these Drawings A represents a portion of the front of the case of
an annunciator, to the rear of which a horizontal shelf B is secured;
an aperture or window C being created in the front A, through which
some one of the characters, to be herein-after referred to, may be seen as
it is exposed by the action of the electric current governed by the
callor.
In rear of the front A, and upon the shelf B, I erect a suitable
frame D composed of two upright standards E, E', and within the upper
part of this frame I mount a horizontal shaft F, provided at one end
with a crank G for readily returning the characters to their normal
position, a spiral spring H being coiled about the shaft and attached to it
and the frame in such manner as to impel the shaft in one direction, for
purposes hereinafter explained. I represents a curved or semi-
cylindrical shield or card, composed of a thin flat band formed into the
segment of a circle, of which the shaft F is the axis, this shield being
mounted upon the shaft by suitable arms J, J, and a hub J', in such
manner as to turn freely upon it in the arc of a circle.
periphery of the shield I, I inscribe, engrave, or otherwise affix a series
of words or characters designating the person or article wanted, such
as waiter, matches, cigars, water, etc., these characters being placed
horizontally upon the shield, and so as to intercept or coincide with
the window C, the size of the latter being such that but one character
is at a time visible through it. A weighted arm or lever K projects
rearward from the shaft F and serves to about counterbalance the weight
of the shield I in order that very little power is necessary to attract
the armature and release the pin from the escapo wheel.
Upon the outer
To the rear side of the shield I, I affix a rib L, and to one side of this
rib I affix two series a, a¹, of horizontal pins 6', 6', etc., which extend
laterally from the rib, the two rows of pins being placed a short
distance apart, and the pin of cach row being equidistant from one
another, while the disposition of the entire number is such that each pin
of one series is equidistant between the two opposite pins of the other
series, as shown in Figure 7 of the Drawings, the rib and pins thus
arranged constituting practically an escape wheel which is governed by

page_text: g
a pallet making part of the armature of the magnet. This armature
is composed of an upright bar 6 pivoted at bottom to a horizontal
fulcrum c extending toward the shield from a lateral shelf or extension d
of the standard E, a horizontal bar or plate e being attached to or
making part of the bar b, and being disposed opposite the ends of an
electro-magnet f, which is disposed in rear of the shield I and supported
by the frame D. The upper extremity of the armature bar 6 terminates
in a lateral horizontal spur or pallet 9 which intercepts some one of the
pins 6 of the escape wheel, the fulcrum of the armature being preferably
so disposed with respect to the two series of pins that the pallet shall
naturally stand between them, the extent of movement of the armature
in one direction being estopped by the magnet which attracts it, and in
the other direction by a suitable stop / against which it abuts by its
own gravity. One wire i of the magnet extends to a suitable electrical
battery, and the other to the room j from which the call is to be made,
a suitable blank wire connecting the room wire with the battery wire,
by which the electric current with the battery is closed or opened at
the will of the caller, while a knob or button is attached to the end of
the wire within the room by which connection with the battery is
established.
When a call is made the shield I drops to a greater or less extent and
to return it to its legitimate position I attach to the shaft F a pin k,
which operates in connection with a second pin affixed to one of the
arms of the shield, as shown in Figure 8 of the Drawings, the spring H
herein-before named serving to return the shaft and its crank to their
original positions and out of the way of the pin in order that the shield
may be free to drop.
A series of instruments or devices as above explained is to be placed
within the case of the annunciator corresponding in number with the
number of apartments with which communication is to be established,
and all the shields or indicators of one row (as there may be several
rows) are to be actuated by one shaft and crank in order that any given
shield after falling and indicating the want of the caller may be "set.
back" by such crank.
When the shield or character card I stands at its highest position the
lowermost pin of the series rests upon the top of the pallet g and the
lowermost character upon the face of the shield is above the window C,
and not visible through it.

page_text: Within each apartment and immediately adjacent to the wire knob
I place a card giving the proper directions for effecting the call, that is
to say, directing the caller to press. the knob once when he desires waiter,
two when he desires cigars, three for coach, etc., and the characters
upon the shield are to be arranged in the order beginning at the bottom
with the instructions within each apartment.
If two or more rows of instruments are employed the cranks of each
series are to be mounted upon one shaft or connected in a suitable
manner, so that the register or display card of any instrument may be
set by one crank.
The operation of my apparatus as above explained is as follows, it
being supposed that the shield is at its highest point as last stated, the
armature away from and unobstructed by the magnet, and the clectrical
circuit with the battery open. A caller desiring a waiter, for instance,
places his thumb or finger upon the knob and by pressing upon it
establishes communication with the battery and closes electrical circuit
with the magnet which attracts the armature and removes the pallet g
from below the pin 6 which rests upon it, and moves such pallet inward
below the next succeeding pin in the opposite series where it remains
until the pressure upon the knob is removed, when the pallet returns to
its orignal position by the opening of the circuit, and allows the shield
to drop a distance sufficient to bring the word waiter in front of the
window C, and thus indicate to the attendant in the office the want
of the caller, each window of course being numbered to correspond
with the number of the room connected with it. If cigars or article
No. 2, whatever it may be, is wanted, the caller presses the knob twice,
which effects a second pulsation of the armature and repeats the closing
and opening of the electrical circuit and brings the second character
in view through the window, and so on throughout the series of
characters.
One battery, which may be maintained at trifling expense, will suffico
to operate a large number of instruments, as the only labor the magnet
has to perform is to release the pallet from one of the pins of the escape
wheel. As the shield is very light and is nearly counterbalanced, the
power required to release the pallet is very slight.
A modification of this mode of signaling would be to employ a number
of stops equal to the number of articles designated on the register, and a

page_text: shall have a name to which it belongs, that is, one stop to water, another
to matches, etc., so that a person desiring a given article shall press the
knob corresponding to such article. In this way but one pressure of the
knob would be necessary to call for any given article on the register.
In lieu of a shield composed of a cylinder or portion of a cylinder
turning upon a horizontal axis, as herein shown, the register may be
affixed to a flat rotary disk having the articles arranged in radial lines
about it.
The sheet of paper upon which the register or list of articles is pivoted
or inscribed is secured to the shield at each end by turning down upon
it the extremity of the shield, as shown in Figure 11 of the Drawings at
a², which constitutes a cheap and perfectly secure attachment.
I have also combined with the herein described annunciator a device
for detecting the presence of fire in any room or apartment with which
the register is connected, and this device consists as follows:-I attach
to any suitable portion of the case a bulb or vessel A³, composed of glass
or any suitable material, and having two cells or chambers, the lower
and large one a³ of which is to receive and contain a quantity of quick-
silver, and the upper and smaller one 6º being to receive any excess of
such quicksilver which the expansion of the latter will force into it, and
which would otherwise burst the bulb. The wire c³ from the battery is
introduced into the small cell 6º, and nearly in contact with the quick-
silver in the chamber a³, or at such a distance that the latter when
subjected to a degree of heat of about 100° Fahrenheit shall expand and
communicate with the said wire, and thereby close the circuit with the
wire d³ which conducts to the register, and which enters the quicksilver
through the bottom of the chamber a².
A character is to be inscribed upon the shield I which shall indicate to
the clerk in the office or the attendant that danger exists, and a like 3
character is to be inscribed upon the card in each guest's room corres-
ponding to this, in order that attention may be called at once in manner
as herein-before explained.
I do not limit myself to the employment of the bulb A2, as herein
reformed to to eat out
17

page_text: tuted. For instance a vial B' may be employed, nearly or quite filled
with quicksilver and its mouth covered with a piece of leather, bladder,
rubber, or other material susceptible of some degree of distension, and so
placed with respect to a tilting arm or lever e² pivoted near it that upon
the heat of the apartment rising to 100° Fahrenheit or thereabouts a
circuit with the battery wire f shall be closed, and the register in the
1
tuted. For instance a vial B³ may be employed, nearly or quite filled
with quicksilver and its mouth covered with a piece of leather, bladder,
rubber, or other material susceptible of some degree of distension, and so
placed with respect to a tilting arm or lever et pivoted near it that upon
the heat of the apartment rising to 100° Fahrenheit or thereabouts a
circuit with the battery wire f shall be closed, and the register in the
office operated.
The bulb A² or its equivalent may be used in connection with a single
bell, or any suitable indicator or alarm in lieu of the mechanism herein
explained. My device may constitute part of a thermometer, and thus
serve a double purpose.
I have apprehended some difficulty in operating the herein described
annunciator from the fact that when an article is wanted which
necessitates several pressures of the knob in a guest's room that their
pressures will be repeated too rapidly. To remedy this I employ in lieu
of the khob which closes the electric circuit instantly a crank or arm
turning upon a pivot and formed with a spur which shall as the crank is
turned abut against and operate the wire leading to the battery.
As it requires one complete revolution of the crank to close the electric
circuit with the annunciator the time required to revolve this crank will
prevent too rapid closing and opening of such circuit, and will remedy
the objection to the knob before referred to.
In place of the above described device or fire alarm I have contem-
plated using the following devico for the same purpose:-I attach to
any suitable portion of the case a short block a¹ of wood, rubber, ivory,
or other material which is a good non-conductor of electricity, and I
bore an axial passage through this block, and close the ends of such
bore, or I otherwise create within the block a cell 6', which is sloping to
the horizon, as shown in Figure 13 of the Drawing, which is a section of
the device. To the under side of the block c* I attach a bulb d' of glass
or other suitable material, the neck e* of which bulb I extend through
the under side of the block, and so that the mouth f' of such neck shall
be on a level with the under surface of the cell 6* at the highest end of
the latter. At some point intermediate between the point where the
neck e intercepts the cell b', say at 9' in the Drawings, I insert within
the block the two wires h*, it, of an electric battery, these two wires also

page_text: of the cello, one of such wires, viz., n', communicating wor
while the other leads to the register.
A character is to be inscribed on the shield I, which shall indicate to
the clerk in the office or the attendant that danger exists, and a like
character is to be inscribed upon the card in each room corresponding to
this, in order that attention may be called at once in manner as herein-
before explained.
Upon the heat of a room acquiring a temperature of 100° Fahrenheit
the mercury with which the bulb d' is filled will expand one or more
drops of it, roll down the bottom of the inclined cell 64, and touch the
ends of the wires *, **, thus establishing electric communication with
them, and closing the circuit for an instant, and give the necessary alarm
at the office.
In lieu of the block c', bulb d', and wires h*, **, as herein described, I :
have contemplated among other equivalents the employment of an open
mouthed bulb or vial ', which I fill with mercury, and cover the mouth
with a piece of rubber, bladder, or other flexible material, and upon this
I poise a spherical ball m*, which is prevented from rolling therefrom
but in one direction by a suitable guard or shield n'. Immediately
adjacent to vial "I dispose an inclined plane or plate o* of a suitable
conducting metal, and at the end of this plate I further arrange an
upright spring p' of a proper conducting metal, the space between the
lower and free end of this spring being slightly less than the diameter of
the sphere m, the plate being pivoted to the vial in order to drop by the
weight of the ball. Upon the temperature of the room 100° Fahrenheit
the mercury in the vial expands and throws the ball from off the mouth
of the vial, and allows it to roll down the inclined plane o'. As the ball
reaches the free end of the spring p' it establishes for an instant electric
communication between the spring which is connected to the battery
wire and the wire q* which leads to the register, and one end of which is
disposed immediately below the tilting plate, as shown in Figure 14 of
the Drawings, which is a section of this device. As the ball strikes the
spring it overcomes the stress of the latter, and drops into a receptacle »
below.
1

page_text: to demonstate that it may be successfully carried out.
CLAIM.
The herein described annunciator and fire indicator as a principle or
in detail, or any improvements or changes therein.
In witness whereof, I, the said Louis Finger, have hereunto set my
hand and seal, this Twenty-ninth day of December, 1873.
The herein described annunciator and fire indicator as a principle or
in detail, or any improvements or changes therein.
In witness whereof, I, the said Louis Finger, have hereunto set my
hand and seal, this Twenty-ninth day of December, 1873.