IMPROVED MECHANISM FOR DISCHARGING ORDNANCE
Year: 1871

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVED MECHANISM FOR DISCHARGING ORDNANCE."-A communica-
tion from abroad by Henry Arden, of Brooklyn, County of Kings,
and State of New York, United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 8th September 1871.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVED MECHANISM FOR DISCHARGING ORDNANCE," to be as
follows:-
It is well known that the pitching and rolling of a ship at sea con-
tinually changes the angle of elevation of the guns, and that it is very
difficult under such circumstances to discharge the guns at the proper
moment.

page_text: The object of this Invention is to provide means for discharging the
gun whenever by the rolling or other motion of the vessel the gun
attains the proper angle of elevation, and for this purpose I employ a
medium apparatus or device which is dependent upon the force of
gravity for its operation, and therefore performs automatically and at
the precise moment what has hitherto depended upon the varying judg-
ment and caprice of the gunner. Ordnance may be fired by the agency
of concussion or of electricity, and this Invention which employs either
of these agents consists in so controlling the said agents that their action
is brought into play only at a prearranged time, or on the fulfilment of
certain prearranged conditions, to effect the discharge of the gun. The
means by which this is accomplished and which form the subject of the
present Invention are substantially the same, and operate in substan-
tially the same way (by causing moving bodies to assume certain relative
positions) whether concussion or electricity be employed. In either casc
I employ two bodies, the one held suspended or free to be moved by
gravity (it may be a liquid, a rolling, or floating body), and the other.
affixed to the vessel and dependent for its motion on the movements of
the vessel, the firing of the gun being effected (by the tripping of the
hammer or the closing of the electric circuit, as the case may be,) only
when under certain prearranged conditions these bodies are caused to
assume certain relative positions, by the attraction of gravity operating
one body and the movement of the vessel operating the other body,
upon which the release of the fulminate takes place and the gun is
fired..
Mechanism operating on the above principle comprises two main
features or parts consisting of the two bodies before mentioned, which
are supported on a base fixed on a stand or on the gun itself, the onc
body moving with the vessel or with the gun on which it is placed,
whilst the other is free and subject to the attraction of gravity. When
electricity is employed this may be effected by means of mercury or
other conducting fluid contained in a tube or other vessel in which are
fixed the two points of a broken electric conductor, one part of which
runs to one pole of a battery and the other to the gun and to the other
pole of the battery, These points are electrically insulated from one
another, and may be adjusted so as just to touch the surface of the
mercury when the section of the water line of the vessel which is in the
same vertical plane with the object to be fired at is at any required
angle with the horizon.

page_text: It is obvious that as soon as the two points touch the mercury
the electric circuit will be completed, and the same when an adjustable
pendulum communicating with one part of the conducting wire touches
a fixed are connected to the other part, both being conductors of
electricity and insulated from one another until brought together by
the action of gravity and the movement of the vessel.
In the circuit formed by the conducting wires is a suitable electric
fuse used for firing the gun, or an electro-magnet may be arranged to
pull a trigger and release a hammer to explode the cap. A key may be
placed in the same circuit to be operated by hand for opening and
closing the circuit, independently of the mechanism before referred to,
so that the discharge of the gun cannot take place until after the
circuit has been closed at that point by the officer in charge pressing.
down the key.
Various methods of operation may be employed according to circum
stances, as for instance, the distance of the object to be fired at being
determined, and the required angle of elevation of the gun being known,
the parts are adjusted accordingly. The gun is then pointed at the
object, its bore being parallel with the deck, no attention being paid to
its elevation or deflection in reference to the horizon by the rolling or
motion of the ship. When everything is ready the apparatus is brought
into play by the officer in charge, and so soon thereafter as the gun
attains the proper angle of elevation or deflection by the rolling or
motion of the vessel the circuit is completed, and the electricity ignites
the fuse or vitallizes the electro-magnet (as the case may be) thereby
firing the gun. It is evident the same apparatus can be used (if desired)
for any number of guns requiring the same angle of elevation and to
be fired at the same object, and the apparatus can be modified,
gravity being in all cases the governing principle..
Another method is to adjust the mechanism to close the circuit when
the section of the water line of the ship, which is in the same vertical
plane with the object to be fired at, is parallel with the plane of the
water; the gun is then elevated in the ordinary manner to the angle
required to send the projectile to the object fired at. When all is ready
for firing the officer in charge presses down the key to restore the
circuit and so soon thereafter as the gun attains the required angle of
elevation to the plane of the water the clectric circuit is completed
and the gun is discharged, or the apparatus may be placed upon

page_text: the barrel of the gun and the contact point of the pendulum be
adjusted at the required angle of elevation or deflection, the gun is
then elevated or deflected gradually, and so soon as it attains the
proper angle with the plane of the water (the controlling key being
properly adjusted by the officer in charge) the electric circuit is com-
pleted and the gun is discharged as before described. The vessel con-
taining the mercury may be attached to the gun carriage, the points of
the electric conductor being connected adjustably with the trunnion
of the gun and moved therewith. Thus arranged the bore of the gun.
may be adjusted in relation to the said points that the gun may be fired
when it is (either by the elevating screw or the motion of the ship)
brought to any previously arranged angle of elevation or depression.
When electricity is not employed a hammer or other solid body may be
so connected with a lever or system of levers or with a rolling or floating
body or with a tube or vessel containing mercury or other liquid that its
liberation and action shall depend upon the force of gravity, the centre of
gravity being constantly varied by the motion of the vessel. The
mechanism is so arranged in relation to the gun and the power by which
the concussion is produced as to prevent the discharge taking place until
the apparatus having been unlatched or set free by the officer in charge,
the one part is brought by the motion of the vessel into a certain position
in respect to the other part, which is subject to the action of gravity,
when the power is released and the gun fired. Various means or devices
may be employed according to circumstances to adjust the one part in
such relation to the other as to effect the discharge of the gun at the
right instant, or when the gun is brought by the motion of the vessel or
otherwise pointed to such an elevation as to send the projectile to the
object fired at.
Mechanism acting on the principle herein-before set forth may be
annlied not only for firing ouns on board ship. but also for guns used

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent; bearing date the. Eighth day of September, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, adminis-
trators, and assigns, or such others as I, the said Alexander Melville
Clark, my executors, administrators, and assigns, should at any time
agree with, and no, others, from time to time and at all times thereafter
O during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "İM-
PROVED MECHANISM FOR DISCHARGING ORDNANCE," a communication to me from
abroad by Henry Arden, of Brooklyn, County of Kings, and State of New
5 York, United States of America, upon the condition (amongst others)
that I, the said Alexander Melville Clark, my executors. or adminis-
trators, by an instrument in writing under my, or their, or one of
their hands and scals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Scal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Sheet of Drawings
hereunto annexed, and to the letters and figures marked thereon (that
is to say) :-
It is well known that the pitching and rolling of a ship at sea
continually changes the angle of elevation of the guns, and that it is
very difficult under such circumstances to discharge the guns at the
proper moment.
The object of this Invention is to provide means for discharging the
gun whenever by the rolling or other motion of the vessel the gun
attains the proper angle of elevation, and for this purpose I employ a
medium apparatus or device which is dependent upon the force of gravity
for its operation, and therefore performs automatically and at the precise

page_text: moment which has hitherto depended upon the varying judgment and
caprice of the gunner.
In the accompanying Sheet of Drawings I have shown various devices
by which the object of the Invention may be accomplished, all operating.
upon the same general principle and dependent upon the force of
gravity for their operation.
In Figure 1, A represents the base of an apparatus which has two
upright stands B, B', to which is pivoted the metallic ring C.
Within the ring is pivoted the metal bar D, the pivots of the ring and of
the bar being equidistant from each other. E is a metallic arc or sector,
the centre of which arc or circle is the centre of the bar D. Upon the
side of this arc the degrees, minutes, and seconds of the angle of
elevation are marked, the zero line being a line which passes through the
centre of the base and perpendicular thereto when the base is horizontal.
F is a pointer or index attached to the bar D which passes over the
arc E, which pointer can be adjusted to any degree, minute, or second of
elevation on the arc that may be desired. G is a metallic point on the
pointer F. From the centre of the base A another arc H is supported,
which is in the same plane as the bar D and at right angles to the
base A. This are H is electrically insulated from the base A and from
the other parts of the machine; K is a wire attached to the arc H,
running to one pole of the battery J; I is another conducting wire
attached to any other part of the machine, and running to the other pole
of the battery. The point G is so adjusted that in passing over the arc H
it touches it, and by so touching closes the circuit of the electric current.
In the circuit formed by these conducting wires is an electric fuse used
for firing the gun. Or an electric magnet is arranged to pull a trigger
and release a hammer to explode the cap. L is a key, also in the same
circuit, for opening and closing the circuit, preferably arranged so as to
close the circuit when the key is pressed down.
:―
The first method of operation which I will describe is as follows:-
The distance of the object to be fired at being determined, and the
required angle of elevation of the gun being known, the pointer F is
The gun is
adjusted to and fastened at this angle as marked on the arc.
then pointed at the object, its bore being parallel with the deck, no
attention being paid to its elevation or deflection in reference to the
horizon by the rolling or motion of the ship. When everything is ready
the key is pressed down, and so soon thereafter as the gun attains the
proper angle of elevation or deflection by the rolling or motion of the

page_text: vessel the point G passes over the arc H, touches it and closes the circuit,
and the electricity ignites the fuse or vitalizes the electro-magnet (as the
case may be) thereby firing the gun. It is evident that this apparatus
can be used (if desired) for any number of guns upon the same vessel
requiring the same angle of elevation and to be fired at the same object.
The same result may be produced by various modifications of this
machine, gravity being in all cases the governing principle.
. A second method of operating the machine is to fasten the arm F to
the are E, so that the point G touches the are H, and thereby closes the
electric circuit when the section of the water line of the ship which is in
the same vertical plane with the object to be fired at is parallel with the
plane of the water, the gun is then clevated in the ordinary manner to
the angle required to send the projectile to the object fired at. When all
is ready for firing (the officer in charge presses down the key L, and so
soon thereafter as the gun attains the required angle of elevation with
the plane of the water the electric circuit is completed by the point G
coming in contact with the arc H, and the electricity passes to the fuse
and ignites it, or to the electro-magnet and vitalizes it, as the case may
|be, thereby firing the gun.
Another and third method of operating the machine is as follows :—
I place the machine upon the barrel of the gun and adjust the arm F
upon the arc E at the required angle of elevation or deflection as marked
upon said arc, the gun is then elevated or deflected gradually, and so
soon as it attains the proper angle with the plane of the water (the key L
being pressed down by the officer in charge) the electric circuit. is
completed by the point G coming in contact with the arc H, and the
electricity passes to the fuse and ignites it, or to the electro-magnet and
vitalizes it, as the case may be, thereby firing the gun.
Instead of employing an oscillating weight or pendulum, as repre-
sented by the arc E, I produce the same result by means of mercury or
other conducting fluid.
Figure 2 shows a bent tube partially filled with mercury. Within the
two ends of this tube are arranged the two points c, c', of a broken
electric conductor, the two parts of which conductor are designated by
d, d. The points c, c', are adjusted so that both just touch the surface
of the mercury when the section of the water line of the vessel which is
in the same vertical plane with the object to be fired at is at any
required angle with the horizon. To effect this adjustment the con-
.

page_text: ductors d, d, screw through caps y, y', on the tube. Preferably I adjust
the points c, c¹, so that they both just touch the mercury, when the
aforesaid section of the water line of the vessel is horizontal, as shown in
the line a, a, in Drawing, and in that case I operate by the second
method described above. I can, however, adjust the points c, c¹, so that
they will both just touch the mercury when the aforesaid section of the
water line of the vessel is at any required angle with the horizon, as for
instance, if the (points be adjusted to the line e, e¹, in which case the
operation is that above described as the first method of operating the
machine. It is of course obvious that as soon as the points c, c', touch
the mercury the electric circuit is completed and the same results
attained as when the point G touches the arc H in Figure 1 as above
shown. It will be seen also that though the vessel should rock and
carry the tube with it to an angle represented by the line e, e¹, the
mercury would remain on a level and the circuit could not be completed
until both of the points. c, c', 'touched the mercury at the same time.
Figure 3 is a simple cup containing mercury, it being a vertical
section of Figure 4 taken on the line x, x, the points being attached to
adjustable screws f,ƒ³, and the operation being the same as in Figure 2;
Figure 4 is a vertical section of Figure 3 taken on the line y, y. The
screw Z is to adjust the height of the mercury in the cup in order to
compensate for the variations in the height of the mercury produced by
the change in temperature or by other causes.
Figure 5 is another modification showing an adjusting piston g by
which the height of the mercury in the tubes h, h, is regulated; i is a
transparent tube equidistant from the tubes h, h, in which tube i the
height of the mercury is always constant without reference to the motion
of the vessel; j is a pointer to indicate the height to which the mercury
should be adjusted by means of the piston g.
Figure 6 is still another modification of the machine when mercury is
employed, the height of the mercury being regulated by the tube k. In
this case when the mercury rises above the tube k (which should be
equidistant from the sides of the cup) it runs through it into the
reservoir below, the tube / serving as an air tube. If by oxydation or
other cause the mercury falls below the top of the tube & the vessel may
be inverted so that the mercury will flow back into the compartment m,
where the tube k would serve as the air tube. The mercury in all these

page_text: oxydation.
In Figure 7 W represents a metallic bar, at the end of which is the
point c, it is bent in the manner shown in the Drawing, and forms part
of the conductor d'. This bar W is free in the top of the tube or its
cap and returns down outside the tube to a supporting plate at such a
distance below that the expansion of the bar W upward will equal that
of the mercury and thus keep the point c always in adjustment. In the
same Figure V is a graduated scale in connection with the pointer r
attached to the adjustable screw f. The point c in this case is adjusted
by bringing the pointer to any required position on the scale V, which
position may
be determined by reference to a thermometer if the adjust-
ment is in reference to variation of the height of the mercury by changes
of atmosphere, or by reference to computed tables if the first above
described method of operating the machine is employed.
L
In Figure 8 the mechanism is attached to the gun carriage and the
points c, c, to a bell crank lever connecting with a link m² and arm n,
the latter of which can be set fast to an arc o secured to the trunnion.
With this arrangement the bore of the gun. may be so adjusted in
relation to the points c, c¹, that the gun may be fired when it is either
by the elevating screw or the motion of the ship brought to any
previously arranged angle of elevation or depression.
Figure 15 shows still another modification of the machine, where the
tube containing mercury and the metallic pointers are arranged as above
described placed upon a plate 70 pivoted to another plate 71 at point 72.
Upon plate 71 is a graduated arc 73 showing the degrees, minutes, and
seconds of elevation, the zero point on this arc being where a line drawn
through the centre of motion 72 of the plate 70 parallel with the horizon
will strike said arc. With this device the gun may be worked according
to the method firstly above described of operating the machine, viz., the
bore of the gun may be always left on a horizontal line or at some known
angle, and the required angle of elevation given to it by adjusting the
plate 70 to the required degree upon the graduated scale 73.
Figures 9 and 10 show a side view and cross section of a piece of
ordnance and the made of
21

page_text: Figures 11 and 12 show a longitudinal and cross section of the friction
primer adapted to this Invention; p is the fulminate of the primer,
and q² is a fine platinum wire by which the ends of the conducting
wires d, d', are connected. The fulminate is exploded when the electrical
circuit is formed as the platinum wire becomes intensely heated at that
moment; represents a piece of wood or equivalent material for
securing the conducting wires in the primer tube. A battery power
sufficient for the purpose may be formed by insulating a zinc plate upon
the outside of the vessel below the water line and in contact with salt
water. Such a device is represented in Figures 13 and 14. The former
Figure shows the side of the vessel with port-hole S¹ and gun w²; u is
the zinc plate insulated from the iron sides of the vessel but exposed to
the action of the salt water, and v² an insulated conducting rod. The
zine plate u forms one of the poles of the battery, and the metallic
sides of the ship the other pole of the battery, from which power is
obtained for exploding the fulminate by means of the electrical circuit
or by vitalizing a magnet brought into play in either case by gravity.
Although I consider electricity in some of the various modes of
application of which it is susceptible as best suited to my purpose and
as producing the most certain and accurate results, I do not by any
means confine myself thereto, as the force of gravity may be made, by
means of levers, pendulums, or rolling or moving bodies to actuate
almost any description of mechanism. A hammer or other solid body
may be so connected with a lever or system of levers, or with a rolling
or floating body, or with a tube or vessel containing mercury or other
liquid, that its liberation and action shall depend upon the force of
gravity, the centre of gravity being constantly varied by the motion of
the vessel. One of the many mechanisms designed to accomplish the
above result by gravity without the employment of electricity is shown
in Figure 16. Such an arrangement will be found convenient in ships'
boats where a battery would be inadmissable. It is also applicable to
guns used on land, particularly for field pieces, as it fixes the elevation
accurately no matter what the character of the foundation. As shown
in said Figure 16 a spiral spring 50 is compressed to the position
represented by a bell crank lever 51, 52, one arm of which 52 has a slot
in its end which catches on a pin 53 in a second lever 54 pivoted at 55,
the free end of which lever 54 is bent and rests on the flange of an
arc 56, which are is attached in a manner capable of adjustment to a
pendulum 58 provided with a heavy weight, a slit 59 is cut in the

page_text: flanged edge of the are 56 through which the bent end of lever 54 drops
when by the motion of the ship the gun attains the previously arranged
angle of elevation. As the lever 54 falls the lever 52 slips off the
stud 53 and the spring 50 retracts quickly and pulls down a hammer on
a percussion cap, or as shown pulls a friction primer and fires the gun.
The parts are returned to the position shown in the Drawing by simply
pushing back the lever 51 as the long end of the arm 52 lifts the lever
54 by means of the stud 53, and the lever 54 being thin is sprung to one
side so that it catches on the are 56 as shown; 57 is a retaining pawl
which also holds up the lever 54.. This is released by the gunner when
he wishes to fire his piece, and so soon after this is done as the proper
angle of elevation is attained the pendulum brings the slit 59 in the
arc 56 into position and releases the spring 50, thus causing the
explosion.
Many modifications of this mechanism can be made founded on the
same principle.
Having described the nature of the Invention and the manner of
performing the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is, a
mechanism or device for firing ordnance when such mechanism or devico
is dependent for its operation upon the force of gravity, substantially as
described and set forth.
In witness whereof, I, the said Alexander Melville Clark, have
- hereunto set my hand and seal, this Fourth day of March,
-
Witness,
W. CLARK,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)