IMPROVEMENTS IN THE CONSTRUCTION OF GUNS AND PROJECTILES, AND OF CARRIAGES, PLATFORMS, AND SHIELDS FOR WORKING AND PROTECTING GUNS."
Year: 1863

page_text: LETTERS PATENT to George Clark, of No. 30, Craven Street, Strand,
Westminster, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN THE CONSTRUCTION OF GUNS AND PROJECTILES, AND
OF CARRIAGES, PLATFORMS, AND SHIELDS FOR WORKING AND PROTECTING
GUNS."
PROVISIONAL SPECIFICATION left by the said George Clark at the
Office of the Commissioners of Patents, with his Petition, on the 27th
June 1868.
I, GEORGE CLARK, of No. 30, Craven Street, Strand, Westminster, in the
County of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF GUNS AND PROJECTILES,
AND OF CARRIAGES, PLATFORMS, AND SHIELDS FOR WORKING AND PROTECTING GUNS,"
to be as follows:-
This Invention consists in the following improvements, herein-after
described:-
1. A mode of rifling, which I term "gravitating guide rifling."
2. The prevention of windage in firing guns without obstruction in loading
or discharging projectiles.

page_text: and expanding ring or disc.
4. A mode of balancing and guiding projectiles in smooth bored guns.
5. A new kind of explosive projectile.
6. A mode of constructing projectiles with false heads and ends.
7. A mode of constructing gun carriages and platforms in combination
with turntables.
8. A system of revolving gun shields and embrasures.
1. The object of the first improvement is to keep the axis of the projectile
concentric with the axis of the bore during the passage of the former out of
the gun. This I effect on the principle of gravitation. When in firing a
projectile from a gun the gunpowder charge is exploded the pressure on the
surface of the rear end of the shot being equal all over, the specific gravity of
the shot gives it a tendency to press and travel upon those parts of the bore
which are below the plane of the horizontal central line of the gun. If the
gun be rifled with grooves the lower ribs or projections on the shot in the case
of straight rifling, and in the case of spiral rifling the lower halves horizontally
of the corresponding ribs or projections on the shot as it passes out of the gun,
will, if of sufficient depth, rest upon the bottom or edges of the grooves which
are below the horizontal central plane of the gun; I therefore provide that
the distance from the axial line of the shot to the apex or outer edge of each
of the ribs or projections on the shot shall be precisely the same as the distance
from the line of axis of the bore of the gun to the bottom of the grooves or
parts of the grooves in the bore which are below the horizontal plane of such
last-named line of axis. I mean this principle to be carried out whether the
rifling be straight or spiral, and whatever may be the number of grooves, but
for spiral rifling I in preference limit the number of grooves to one, two, three,
or four. Any greater number would tend to jam the shot in passing out of
the gun. In order to preserve to a rifled gun as much as possible the
'character of a smooth bored gun, and limit the escape of explosive gas through
the grooves, in some cases I prefer only two grooves, or even one groove. If I
'use two grooves for straight rifling I form one at the top and one at the bottom
of the bore on the vertical plane of its axis, and for spiral-rifling I form the
grooves so that they commence at points in the breech at the top and bottom
of the bore vertical to its axis and end at similar points at the extremity of the
muzzle. If I form only one groove it runs for straight rifling from the breech
to the muzzle at the bottom of the bore on the vertical plane of its axis, and
for spiral rifling from a point at the top of the breech to a point at the bottom
of the extremity of the muzzle vertical to the axis of the bore.

page_text: The following Diagram and references show the mode of applying the
gravitating guide system to a four-grooved spiral rifled gun.. The pitch of the
spiral grooves is a half turn in their length.
The parallel lines (a, a,) represent the bore of the gun; (b, b,) the axis of
the bore and of the projectile; (c, d, e,) a groove from the top of the breech
to the bottom end of the muzzle; (f, d, g,) a groove from the bottom of the
breech to the top end of the muzzle; (h, i, k,) a top side groove; (h, 1, k,) a
bottom side groove. I form the grooves or parts of grooves d, e, f, d, and
h, l, k, which are below the horizontal plane of the axis th to of an inch, more
or less in depth, and each the same depth precisely; and I form the grooves
or parts of grooves c, d, d, g, and h, i, k, which are above the horizontal plane
of the axis, th of an inch or thereabouts more in depth than the first-named
grooves, so that the ribs or projections on the shot at their outer edge.or
apex being all the same distance from the axis of the shot as the bottom of
the lower grooves is from the axis of the bore, shall rest on the lower grooves,
and not touch the top of the upper grooves (which are somewhat deeper), but
be retained in them without pressure by their sides. I make the cylindrical
part of the projectile th to of an inch or thereabouts less in diameter than
the bore of the gun. By these arrangements when the shot is propelled from
the
gun there is no contact between the cylinder of the projectile and the
bore, and no continuous contact between the ribs and grooves except at those
parts where the edges of the lower ribs press upon the lower grooves, con-
sequently there is no continuous friction except at those parts. The shot will
travel fairly on the bottom grooves without any jamming of the projectile.at
the rifling, whether straight or spiral, and the axis of the projectile will be
concentric with: the axis of the bore from the time the former is set in motion
till it makes its exit from the gun. This gravitating guide system is peculiarly
adapted for straight shooting, without imparting, a rotary motion, and con-
sequently without spiral rifling, but it is also applicable to spiral rifled guns.
For the purpose of converting an ordinary smooth bore gun into a gun on this
system I form in the manner herein-before described one, two, three, or four

page_text: straight grooves, of which I prefer that always one should run along the
bottom of the bore on the vertical plane of its axis.
2. My improvement in the construction of projectiles of which the object
is the prevention of windage in firing guns without obstruction in loading or
discharging shot, I effect in the following manner :-I employ an elongated
cylindrical projectile, of which I reduce the circumference of a part or parts,
and thus form a recess or recesses in the circumference of the shot between
its extremities, I insert and retain therein metallic india-rubber or other elastic
rings or hoops forming circular springs which, acting in the same manner as
packing to a steam piston, will press equally on the surface of the bore
of the gun and prevent the escape of gas. At the back of the springs or
packing I leave a space for sufficient play of the spring to prevent rigid
resistance at any point as the shot passes out of the gun. The lateral
résistance of the spring or packing should be slight, so as to yield readily to side
pressure as the shot enters or passes out of the gun.
This improvement may be applied to shot for smooth bored guns, but it is
especially applicable to rifled projectiles, and may be used with any kind of
groved gun, straight or spiral. The rifled ribs or projections of the
projectile are formed on the ends of the shot before and behind the springs or
packing. To prevent obstruction from the air in the gun in loading, I make
a provision to allow the air to escape as the shot is rammed into the gun
through channels at the back of the springs or packing or through a hole or holes
in the projectile itself, and I use a valve or valves which admit the passage of the
expelled air and close when the shot is rammed home. The escape of gas when
the powder is fired being prevented, the whole of the explosive force will be
made available to propel the shot.
The annexed Diagrams, Sheets 1 and 2, illustrate the details of this improve-
ment. Fig. 1 is à sectional plan of a spiral rifled projectile; Fig. 2 is a sectional
plan and view of the bore of a gun loaded with a spiral rifled projectile; Fig. 3
is a transverse section at A, B, of a gun loaded with a spiral rifled projectile;
Fig. 4 is a transverse section at C, D, of a projectile with the anti-windage spring
packing open; Fig. 5 is a transverse section of the same at E, F, with the anti-
wndage spring packing closed; Fig. 6 is a transverse section at G, H, of a pro-
jectile and a hōoy which retains the spring on the plan shown in the Diagrains
Figs. 1 and 2; Fig. 7 is a transverse section of a projectile with a ring spring
or packing let into a circular channel round the circumference of the shot. In
these Diagrams the same letters denote the same parts.
.
a, a, the gun; b, b, the bore of the gun; 'c, c, the projectile; d, d, the screw
end of the projectile when made hollow; e, e, the hollow of the projectile to

page_text: reduce its weight; ff, air channel plate; 9, 9, rifled ribs on projectile; h, h,
anti-windage spring or packing; i, i, collar screwed to projectile in sections and
retaining the spring; k, k, spring valve regulating the passage of the air. It
remains open and allows the escape of air whilst the gun is being loaded with
the projectile. It closes when the shot is rammed home and remains closed by
the action of a spring catch so as to prevent the escape of gas through the air
passages when the charge explodes; !, !, air channels allowing the escape
of air behind the anti-windage springs h, h. The projectile is represented as
hollow in the Diagrams, but it may be solid. I also allow the air to. escape
by a hole perforated through the shot as shewn by red lines Figs. 1, 2, 3,
and 6, and lettered (m). The spring packing may be placed in recesses
round the projectile at any part of its length, but I prefer placing it midway
between the extremities or at the end next to the breech of the gun.
3. The following is another of my improvements in the construction of
projectiles of which the object is to allow windage when the gun is loaded and
prevent the escape of explosive gas when it is fired. At the rear end of a
cylindrical shot I fix a compressible ring or disc forming a pad or cushion
between the body of the projectile and a compressing plate, which is held in
position by a screw, with a dovetailed head. The ring or disc is made of
soft metal or some other compressible material, which being compressed will
expand laterally and exude at the edges when the explosive force acts on the
compressing plate. Sufficient windage space being allowed to load the gun
with the projectile, this space at the moment of the explosion of the charge
will be filled and made gas-tight by the protruding edges of the expanding
ring or disc. More than one ring or disc may be used if expedient.
In Figs. 11 and 12 of the annexed Diagrams the arrangement is shown.
a is the body of the shot; b, a false head on the plan herein-after described;
c, the compressing plate, which in Fig. 12 is bevilled, so as to have a tendency to
thrust the compressible material outwards; d, the conical headed screw; s, the
expanding ring or disc; soft metal, or any other tough and compressible
material may be used for the ring or disc, but I recommend for the purpose
metallic cloth with an admixture of or in combination with india-rubber, wool,
cotton, felt, or other fibrous matter. This improvement is applicable to
smooth bored or rifled guns.
:
Another mode of applying the aforesaid combination of a compressing plate
and compressible ring or disc for the prevention of windage, is to allow the
yielding material confined by the compressing plate to extend a little outside
the periphery of the projectile, so as to form packing between the projectile
and the bore, and provide for the escape of air in loading the gun by

page_text: channels through it or at its sides. Under this arrangement the difference
beween the diameter of the shot and the bore of the gun may be somewhat
increased.
4. Another of my improvements in the construction of projectiles has for its
principal object straight shooting with an elongated shot from a smooth bored
gun. This I propose to effect by balancing the projectile on the edges or
points of slightly convex ribs or projections formed on its surface; I consider
six such ribs or series of points a suitable number, but any larger or smaller
number may be employed. These ribs or points are made to fit closely to the
bore of the gun, and will keep the shot concentric or nearly so to the bore;
spaces for windage between the cylinder of the shot and the bore will be left
between the ribs or points. However narrow these spaces may be there will
be no friction of the shot against the bore, except that of the projecting ribs
or points, and this. amount of friction may be reduced in the case of ribs being
formed by cutting them away round the centre of the circumference of the
cylinder, and leaving at both ends short ribs, on which or on points distant
from each other the shot will be balanced and travel out of the gun true to its
concentricity with the axis of the bore. The mode of construction I propose
to adopt is to turn the metallic cylinder of which the projectile is to be formed
to a close fit to the bore, and then to form the ribs or points above referred to
by planing off so much of the surface between them, say th or th of an inch
from the diameter, more or less, as may be necessary to allow the windage
required for loading. For projectiles of cast metal the ribs may be formed in
casting them. Fig. 13 is a transverse section of a rib or point balanced
projectile. This improvement may be applied to solid or hollow projectiles,
and used by itself or in combination with the expanding ring or disc herein-
before described and shown in Figs. 11 and 12.
.
5. The fifth improvement is the construction of a hollow globe perforated
with a number of holes like a Chinese ivory ball. Inside the globe is a
chamber of a fragile construction containing priming and an explosive
substance. Rods or bars of iron or other metal are thrust through the holes
of the globe, and are placed with one set of their ends abutting against the
chamber, and the other ends protruding from the holes in the globe, which
being charged with gunpowder is enclosed in two cups or hemispheres of thin
metal securely fastened together by screwing of otherwise. This projectile
being propelled, on its striking against a body the concussion of impact will.
cause one or other of the rods or bars protruding through the perforations in
the globe to produce by percussion combustion in the priming chamber and
explosion of the projectile..
:

page_text: 6. The object of my sixth improvement in projectiles is to construct them
with a false conical or other shaped head or end on a plan which shall aid
their flight by reducing friction in cleaving the air, but shall not be detrimental
to their destructive force, and which may be made available for other purposes.
This I accomplish by forming a cap or cover of thin metal, or any other suit-
able material, and fastening the same, by screws or otherwise, to the head or
end of the projectile as may be required according to the purpose to which it
is to be applied. The head of the shot itself may be flat or spherical. If a
conical cap on this plan be fixed on the head of the shot, the result will be
that at the moment of impact, the conical cap being purposely made slight and
fragile, will be instantaneously crushed and destroyed, and the solid head of
the shot, whether flat or spherical, will produce its full effect, as the absorption
of force in destroying the cap will be trifling. I have mentioned that I some-
times provide for the escape of air from the gun in loading it through a hole
in the projectile. That arrangement will be facilitated by the use of the false
head or conical cap, as shown in the Diagrams Figs. 1, 2, 3, 6, and coloured red,
in which n is a valve, which opens for the escape of air but closes of itself with a
spring; o; o, is the conical cap; p. p, small holes in the cap for the escape of
air. The other uses for which I propose to make the false heads or ends
available are charging them with gunpowder or explosive composition to cause
them to act as shells, or as fusees or rockets, to sustain or increase projectile
force. For the purpose of giving rotary motion on its axis to the projectile in
its flight through the air, I construct the conical false head herein-before.
described with convoluted ridges or vanes, running in a spiral direction exter-
nally from the base, to or towards the apex of the cone, as shewn at q, q, in
Diagram Fig. 2.
7 and 8. My improved method of working and protecting guns is 'designed for
facilitating the use of the heaviest ordnance. It is composed of two parts, which
in practice will be conveniently employed in combination. I construct a
platform of great solidity and strength, capable of carrying the gun and its
carriage with a gun shield built on the platform at one end, and a turntable
upon it at the other end. The platform rests upon a pivot as its centre,
round which it traverses or revolves. on wheels or rollers in the manner of an
ordinary gun platform. On the front end of the platform I construct an armour-
plated gun shield of the dimensions and strength required for the gun to be
worked, and the projectiles to be resisted. The lower part of this shield is.
covered and protected by a fixed parapet up to the line of the bottom of the
embrasure of the shield, and its sides are covered and protected with the fixed
armour plated wall or structure behind which it is placed. In training the

page_text: gun horizontally, the shield being on the platform which carries the gun, the
embrasure turns with the muzzle protruding through it, and therefore it may
be of the same width as the muzzle. When the muzzle does not project out-
side the embrasure, the shield can be turned inwards, so that the embrasure
will be masked and protected by the armour-plated wall or structure which
covers the shield on either side. Two advantages may be obtained from this
arrangement. The lateral range may be greatly increased, and the gun as
well as the gunners protected when the gun is turned inwards. On the rear
end of the platform I construct a turntable, which rests upon and traverses
with the platform, and is so placed and arranged thereon that the gun when
fired may with its carriage recoil on to the turntable, or be afterwards drawn
upon it. The gun may then be turned round to a convenient position for
loading. The moment after the gun has been fired, a quarter circle turn,
more or less, of the platform will bring the embrasure inside the armour-plated
side defences of the shield. The Diagrams, Figs. 8, 9, and 10, Sheet 3, illustrate
these improvements. Fig. 8 is an elevation; Fig. 9 a plan; and Fig. 10-a
side view of the gun platform, with the shield and turntable upon it..
a, a, is the platform; b, b, the gun shield; c, c, the einbrasure; d, d, the
parapet; e, e, the side defences, being part of the main structure; f.f, the
turntable; 9, 9, the roof or deck of the main structure. The parts of these
improvements may be used separately or in combination, and they are or
either of them is applicable to forts, ships, or batteries, stationary or moveable.
The platform, instead of traversing on a pivot as shown in the Drawing, Fig. 10,
may be supported by rollers, or balls and sockets with univeral joints, resting
on an incline, on which the platform with its superstructures and the gun
may recoil when the front of the shield is struck by projectiles.
Of the improvements herein-before described forming parts of my Invention,
those which relate to the construction or rifling of guns and projectiles, are
respectively applicable to muzzle or breech-loading guns, or to solid or hollow
shot. Those for the prevention of windage, described under Numbers 2 and 3,
are applicable to sabots of wood, metal, or other material, placed between the
gunpowder charge and the projectile. All the said improvements in rifling, or
for the prevention of windage, are chiefly designed for great guns, but I intend
that any of such improvements as are applicable to shall be used for small
arms, and each of the aforesaid improvements, whether relating to guns or
projectiles, or to gun carriages, platforms, or shields, may be used separately
or in combination with all or any of the other improvements.

page_text: SPECIFICATION filed in pursuance of the conditions of the Letters Patent,
and of an Order of the Lord Chancellor, by the said George Clark in
the Great Seal Patent Office on the 26th January 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
CLARK, of No. 30, Craven Street, Strand, Westminster, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of June, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said George Clark, Her special licence that I, the said George Clark,
my executors, administrators, and assigns, or such others as I, the said
George Clark, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter 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 "IMPROVEMENTS IN
THE CONSTRUCTION OF GUNS AND PROJECTILES, AND OF CARRIAGES, PLATFORMS, AND
SHIELDS FOR WORKING AND PROTECTING GUNS," upon the condition (amongst
others) that I, the said George Clark, my executors or administrators, by an.
instrument in writing under my, or their, or one of their hands and seals,
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 Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Clark, do hereby declare
the nature of my said Invention, and in what manner the same is to be per.
formed, to be particularly described and ascertained in and by the following
statement:-
'This Invention consists in the following improvements, which are herein-
after described under their respective heads.
1. A mode of rifling and boring guns, which I term "the gravitation guide
system.
2. The prevention or reduction of windage in firing guns without obstruc-
tion in loading or discharging projectiles..
3. A mode of obviating the effects of windage by means of a compressible
and expanding ring or disc.

page_text: 4. A mode of balancing and guiding projectiles in smooth-bored guns.
5. A new kind of explosive projectile.
6. A mode of constructing projectiles with false heads and ends.
7. A mode of constructing gun carriages and platforms in combination with
turntables for working guns.
8. A system of revolving gun shields and embrasures.
1. The object of the first improvement is to keep the axis of the projectile
concentric with the axis of the bore of the gun and obtain uniform windage,
or a close fit of the projectile in the bore during the passage of the former
out of the gun. This I effect on the principle of gravitation. When in firing
a projectile from a gun the gunpowder charge is ignited, the pressure of the
explosive gas on the surface of the rear end of the shot being equal all over,
the specific gravity of the shot gives it a tendency to press and travel upon.
those parts of the bore which are below the plane of the horizontal central
line of the bore of the gun. If the gun be rifled with grooves the lower ribs
or projections on the shot in the case of straight rifling, and in the case of
spiral rifling the lower halves horizontally of the ribs or projections on the
shot, if their depth and dimensions correspond with those of the grooves, will,
as the projectile passes out of the gun, rest upon the bottom or edges of the.
grooves, which are below the horizontal central plane of the bore of the gun.
I therefore provide that the radii of the ribs on the projectile, that is to say,
the distance from the axial line of the shot to the apex or outer edge of each
of the ribs or projections on the shot shall be precisely the same as the length
of the radii of the bore, or the distance from the axis of the bore of the gun
to the bottom of the grooves or parts of the grooves in the bore which are
below the horizontal plane of such last-named line of axis. I mean this
principle to be carried out whether the rifling be straight or spiral, and what-
ever may be the number of grooves, but for spiral rifling I, in preference,
limit the number of grooves to one, two, three, or four; any greater number
might tend to jam the shot in passing out of the gun, but nevertheless might
be used as an application of the gravitating principle. In order to preserve
to a rifled gun, as much as possible, the character of a smooth-bored gun, and
limit the escape of explosive gas through the grooves, in some cases I prefer
only two grooves or even one groove. If I used two grooves, I should for
straight rifling form one at the top and one at the bottom of the bore on the
vertical plane of its axis, and for spiral rifling I should form the grooves so
that they commenced at points in the breech at the top and bottom of the
bore vertical to its axis, and ended at similar points at the extremity of the
muzzle; or in some cases both the grooves might be at the bottom of the bore.

page_text: 66
Throughout this description, whenever I use the words
"bottom of the bore," or "top of the bore," or "lower
grooves," or upper grooves," I mean the half of the
bore below or above the horizontal plane of its axis
longitudinally, or the grooves below or above that line
If I formed only onė groove it should run for straight
rifling from the breech to the muzzle at the bottom
of the bore on the vertical plane of its axis, and for
spiral rifling from a point at the breech to a point at the
extremity of the muzzle along the bottom of the bore.
The following Diagram and references show the mode
of applying the gravitation guide system to a four
grooved spiral rifled gun, supposing the pitch of the
spiral grooves to be a half-turn in their length.
The parallel lines' (a, a,) represent the bore of the
gun; (b, b,) the axis of the bore and of the projectile
(c, d, e,) a groove from the top of. the breech to the
bottom. end of the muzzle; (f, d, g,) a groove from th
bottom of the breech to the top end of the. muzzle
(h, i, k,) a top side groove; (h, 1, k,) a bottom sid
groove. I form the grooves or parts of grooves (d, e,
(f, d.) and (h,l, k,) which are below the horizontal plan
of the axis th to of an inch, more or less, in depth
and each the same depth precisely, and I form th
grooves or parts of grooves (c, d) (d, g,) and (h, i, k,
which are above the horizontal plane of the axis th c
an inch or thereabouts more in depth than the first
named grooves, as represented by the double lines i
the Diagram, so that the ribs or projections on the sho
at their outer edge or apex being all the same distanc
from the axis, of the shot as. the bottom of the lowe
grooves is from the axis of the bore, shall not touch th
top of the upper grooves, (which are somewhat deeper,
but be retained in them, without pressure, by: the
sides. I make the cylindrical part of the projectile
to of an inch or thereabouts less in diameter tha
the bore of the gun. By these arrangements when th
shot is propelled from the gun there is no conta
between the cylinder of the projectile and the bor

page_text: and no continuous contact between the ribs and grooves, except at those
parts where the edges of the lower ribs press upon the lower grooves,
consequently there is no continuous friction except at those parts. The
shot will travel fairly on the bottom grooves without any strain on opposite
sides of the gun, and without any jamming of the projectile at the rifling,.
whether straight or spiral, and the axis of the projectile will be con-
centric with the axis of the bore from the time the former is set in motion till
it makes its exit from the gun. This gravitating guide system is applicable
for straight shooting, by means of straight grooves and ribs, without imparting
a rotating motion to the projectile, as well as to spiral rifled guns. For the
purpose of converting an ordinary smooth bored gun into a rifled gun on
this system, I form in the bore of the gun any required number of straight
or spiral grooves in the manner herein-before described. If I wish to apply
the gravitating principle to a smooth bored gun without rifling, I slightly
increase the diameter of the upper half of the bore, and make the circum-
ference of the projectile a close fit to the lower half of the bore, leaving all
the windage at the upper half of the bore.
Another mode of applying the gravitating principle is to form the rifled
grooves at the lower half only of the bore, without any grooves at the upper
half of the bore, with ribs on only one side of the projectile. But in the case
of spiral rifling this mode can only be applied when the pitch of the twist does
not exceed a turn of one-fourth in the length of the grooves in the bore.
The gravitating principle of rifling may be applied to guns rifled with ribs in
the bore by forming ribs in the upper half of the bore slightly less in pro-
jection from the bore than the ribs in the lower half of the bore, so that the
grooves in the projectile being all of equal depth, and sliding on and over the
lower ribs, shall not come in contact with the outside of the upper ribs.
The gravitating principle is illustrated in the annexed Sheet of Drawings
by the Diagram Fig. 1, to which the following letters refer :-(a), the gun
rifled with four grooves; (b), the projectile with four ribs; (c), the centre of
the bore and of the projectile; (d), the ribs of the projectile, being equal
radii from its centre and fitting into the lower grooves; (e), the upper grooves
enlarged; (f), windage space, equal all round.
The gravitation principle, which is the basis of my Invention of rifling guns
and projectiles under this Patent admits of spiral rifling for the purpose of
imparting rotary motion to projectiles, being applied to guns in either of the
following ways, that is to say:-1st, spiral grooves are formed on the surface
of projectiles to be used in smooth-bored guns, the cylinder of the projectile
being a mechanical fit into the lower half of the bore and somewhat less in

page_text: diameter than the upper balf of the bore; 2nd, on the lower half of the bore
spiral ribs slightly in relief or spiral grooves of little depth are formed, and the
upper half of the bore is bored smooth and a little larger in diameter than the
lower half. The projectile fired from the bore of a gun thus rified may
be of a spherical or cylindrical form; its surface will be smooth and its
diameter will be that of the lower half of the bore if grooved, or so much less
than the diameter as the elevation of the rifling if ribs be formed on the bore,
leaving the requisite windage at the upper half. The material of the pro-
jectile may be hard or soft metal, or hard metal coated with soft metal, or any
suitable yielding material. The resistance or friction of the surfaces in close
contact at the lower half of the bore will produce rotary motion in the pro-
jectile when propelled from the gun. The principal object in making
projectiles hollow for the purpose of applying them to my gravitation guide
system of rifling is, to obtain length in the cylindrical form without the
excessive increase of weight which results from making projectiles in solid
cylinders. Another object in making projectiles having round or conical
heads in the cylindrical form for the same purpose is to give to the front of
the shot the required weight, by making that part solid and the rear part
hollow. In order to carry out those two objects more advantageously and at
the same time preserve the equilibrium of the projectile longitudinally, which
I have ascertained by experiment is an essential condition in the practical
application of the gravitation principle, I propose filling the hollow part of the
projectile, as shewn in Fig. 9, letter f, of the annexed Drawings, with some
material of suitable hardness, toughness, and weight; for that purpose wood
may be used, but I prefer a compound of vegetable pulp or fibre or any
pulverised mineral with fatty, oily, gelatinous, bituminous, or resinous sub-
stances, or Portland or Roman or any other cement or concrete, or sulphate
of lime, or "papier maché," or any other compound or material, which, being
employed in a semi-fluid, soft, or doughy state to fill the hollow space in the
projectile wholly or in part, will set and become hard and tough.
2. My improvement in the construction of projectiles of which the object is
the prevention of windage in firing guns without obstruction in loading or
discharging shot, I effect in the following manner :-I employ an elongated
cylindrical projectile, of which I reduce the circumference of a part or parts,
and thus form a recess or recesses in the circumference of the shot between
its extremities. I insert and retain therein rings or hoops of metal, india-
rubber, or any kind of elastic or yielding material, forming circular springs or
compressors, which, acting in the same manner as packing to a steam piston,
will press equally on the surface of the bore of the gun and prevent the escape

page_text: י.
of gas. At the back of the springs or packing I leave a space for sufficient
play of the spring to prevent rigid resistance at any point as the shot passes
out of the gun. The lateral resistance of the spring or packing should be
slight, so as to yield readily to side pressure as the shot enters or passes out of
the gun. This improvement may be applied to shot for smooth bored guns,
but it is especially applicable to rifled projectiles, and may be used with any
.. kind of grooved rifled gun, straight or spiral. To prevent obstruction from
the air in the gun in loading I make a provision to allow the air to escape as
the shot is rammed into the gun, through channels at the back of the springs or
packing, or through a hole or holes in the projectile itself, and I use a valve or
valves which admit the passage of the expelled air in loading the gun, and
close when the shot is rammed home. The escape of gas when the powder is
*fired being prevented, the whole of the explosive force will be made available
'to propel the shot...
The Diagrams in the annexed Sheet of Drawings illustrate the details of
this improvement.
~ Fig. 2 is a sectional plan of a spiral rifled projectile; Fig. 3 is a sectional
plan and view of the bore of a gun loaded with a spiral rifled projectile; Fig. 4
is a transverse section on a larger scale of a gun loaded with a spiral rifled
projectile; Fig. 5 is a transverse section at C, D, of a projectile with the
anti-windage spring packing open; Fig. 6 is a transverse section of the same
at E, F, with the anti-windage spring packing closed; Fig. 7 is a transverse
section at G, H, of a projectile, and a hoop or ring which retains the spring on
the plan shewn in the Diagrams Figs. 2 and 3; Fig. 8 is a transverse
.section of a projectile with a ring spring or packing spring over and let into a
circular channel round the circumference of the shot, the slit in the hoop being
shewn at (S). In these Diagrams the same letters denote the same parts.
"
(a, a,) the gun; (b, b,) the bore of the gun; (c, c,) the projectile; (d, d;)
the screw end of the projectile when made hollow; (e, e,) the hollow of the
projectile to reduce its weight; (f.f.) air channel plate; (9,9,) rifled ribs on
projectile; (h,h,) anti-windage spring or packing; (i, i,) collar screwed to
projectile in sections, and retaining the spring; (k, k,) spring valve regulating
the passage of the air. It remains open and allows the escape of air whilst
the gun is being loaded with the projectile; it closes when the shot is rammed
-home, and remains closed by the action of a spring catch so to prevent the
'escape of gas through the air passages when the charge explodes; (l, l,) air
"channels allowing the escape of air behind the anti-windage springs h, h.
The projectile is represented as hollow in the Diagrams, but it may be solid;
the air may also escape by a hole or holes (m), perforated through the shot.

page_text: The spring packing may be placed in recesses round the projectile at any part
of its length, but I prefer placing it midway between the extremities or at-the
end next to the breech of the gun. In using the ring packing holes for
windage (m) may be perforated in the projectile behind the rings.
3. The following is another of my improvements in the construction of
projectiles of which the object is to allow windage when the gun is loaded and
prevent the escape of explosive gas when it is fired. At the rear end of a
cylindrical shot I fix a compressible ring or dise, forming a pad or cushion,
between the body of the projectile and a compressing plate which is held in
position by a screw with a dovetailed head. The ring or disc is made of very
soft metal or any compressible material which, being compressed, will expand
laterally and exude at the edges of the compressing plate when the explosive
force acts upon it. Sufficient windage space being allowed to load the-gun
with the projectile, this space, at the moment of the explosion of the charge,
will be filled and made gas-tight by the protruding edges of the expanding
ring or disc. More than one ring or disc may be used if expedient.
In Figs. 9 and 10 of the annexed Diagrams the arrangement is shown.
(a) is the body of the shot; (b) a false head on the plan herein-after
described; (c) the compressing plate, which in Fig. 9 is bevilled so as to have
a tendency to thrust the compressible material outwards; (d) the conical-
headed screw; (e) the expanding ring or disc; a convex dotted line shows
how the compressed material will expand outwards. Soft metal or any com-
pressible material may be used for the ring or disc. In my Provisional
Specification I recommended for that purpose metallic cloth with an admixture
of or in combination with india-rubber, wool, cotton, felt, or other fibrous
material, and I am still of opinion that for heavy ordnance projectiles mate-
rials of that description may be used advantageously. But from experiments
I have made I give the preference to a composite substance for the aforesaid
compressible pad or cushion consisting of any fibrous or soft-material in small
particles mixed with melted tallow or grease, or a compound of tallow, wax,
or stearine and shellac, or any resinous or bituminous material, to which any
required degree of hardness and toughness may be given by varying the
proportions of the materials employed. This improvement is applicable to
smooth bored or rifled guns. Another mode of applying the aforesaid com-
bination of a compressing plate and compressible ring or disc for the preven-
tion of windage is to allow the yielding material confined by the compressing
plate to extend a little outside the periphery of the projectile, so as to.form
packing between the projectile and the bore and provide for the escape of air
-in loading the gun by channels through it, or at its sides. Under this arrange-

page_text: .ment the difference between the diameter of the shot and the bore of the
gun might be somewhat increased. This part of my Invention must not be
.confounded with the arrangements of different plans of rifling by means of
expanding materials placed at the breech end of projectiles for the purpose of
.forcing the expanded material into grooves in the bore of the gun. I am well
. acquainted with those plans of rifling of which Mr. Bashley Britten's is one
.example. My improvement of compressible plates or rings at the rear of the
.projectile is not intended or calculated to produce rotary motion by expansion,
.but simply to stop or diminish windage, for which purpose the materials used,
whatever they may be, should be so soft and yielding as to offer no obstruc-
tion to the free rotation of the projectile on my gravitation or non-resisting
.system.
4. Another of my improvements in the construction of projectiles has for
its principal object straight shooting with, an elongated shot from a smooth
bored gun. This I I propose to effect by balancing the projectile on the edges
or points of slightly convex ribs or projections formed on its surface. I con-
sider six such ribs or lines of points a suitable number, but any larger or
smaller number may be employed. These ribs or points are made to fit
closely to the lower half of the bore of the gun, and will keep the shot con-
centric, or nearly so, to the bore. Spaces for windage between the cylinder
of the shot and the bore will be left between the ribs or points. However
narrow these spaces may be, there will be no friction of the shot against the
bore except that of the projecting ribs or points, and this amount of friction
may be reduced in the case of ribs being formed by cutting them away round
the centre of the projectile longitudinally and leaving at both ends short ribs,
on which the shot will be balanced and travel out of the gun true to its con-
centricity with the axis of the bore. The mode of construction for the
formation of these ribs or projections which I propose to adopt is to turn the
metallic cylinder of which the projectile is to be formed to a close fit to
the bore, and then to form the ribs or points above referred to by planing or
turning off so much of the surface between them, say, th or oth of an inch
from. the diameter, more or less, as may be necessary to allow the windage
required for loading. For projectiles of cast metal the ribs may be formed in
casting them.
Fig. 11 is a transverse section of a rib or point-balanced projectile. This
improvement may be applied with straight or spiral ribs or lines of points, and
used by itself or in combination with the gravitating principle, by making the
upper half of the bore slightly larger in diameter than the lower half. (a)
body of the projectile; (b) ribs or points.

page_text: 5. The fifth improvement is the construction of a hollow metallic globe.
perforated with a number of holes, like a Chinese ivory ball. Inside the
globe is a chamber of a fragile construction, containing priming and an
explosive substance. Rods or bars of iron or other metal are thrust through
the holes of the globe, and are placed with one set of their ends abutting
against the priming chamber, and the other ends protruding from the holes in
the globe, which, being charged with gunpowder, is enclosed in two cups or
hemispheres of thin metal securely fastened together by screwing or other-
wise. This projectile being propelled on its striking against a body, the con-
cussion of impact will cause one or other of the rods or bars protruding through
the perforations in the globe to produce by percussion combustion in the
priming chamber and explosion of the bursting charge of the projectile. The
same result may be obtained with elongated projectiles by a similar arrangement
with a sperical or flat front covered with a false heaad or end of thin metal.
6. The object of my sixth.improvement is to construct projectiles with a
false conical or other shaped head or end on a plan which shall aid their flight,
by increasing their length without adding materially to their weight, and by
reducing friction in cleaving the air, but shall not be detrimental to their
destructive force, and which may be made available for other purposes,
especially to make the centre of gravity of a cylindrical projectile coincident
with its meta centre. This object I accomplish by forming a cap or cover of
thin metal or any other suitable material, and fastening the same by screws or
otherwise to the head or end of the projectile as may be required, according
to the purpose to which it is to be applied. The head of the shot itself may
be flat, conical, or spherical. If a conical cap on this plan be fixed on the
head of the shot, the result will be that at the moment of impact, the conical
cap being purposely made slight and fragile, will be instantaneously crushed
and destroyed, and the solid head of the shot will produce its full effect, as the
absorption of force to destroy the cap will be trifling. I have mentioned that
I sometimes provide for the escape of air from the gun in loading it, through
a hole in the projectile. That arrangement will be facilitated by the use of a
false head or conical cap, as shown in the Diagrams Fig. 2, 3, in which (n)
is a valve, which opens for the escape of air, but closes of itself with a spring;
(o, o,) is the conical cap; (p, p) small holes in the cap for the escape of air;
(9, 9, vanes or ridges: The uses for which I propose to make the false end
and hollow space in the projectile available, in addition to that of regulating
the centre of gravity of a cylindrical projectile as already mentioned, are
charging them with gunpowder or explosive composition, to cause them to act
as shells or as fusees or rockets, to sustain or increase the flight and force of

page_text: the projectile. For the purpose of giving rotary motion on its axis to the
projectile in its flight through the air, the conical false head herein-before
described may be constructed with convoluted ridges or vanes running in a
spiral direction externally from the base to or towards the apex of the cone,
as shown at (9,9,) in diagram Fig. 3, or vanes may be in like manner affixed to
the exterior of the false end, but I do not claim the use of such ridges or
vanes as a part of my Invention.
7 and 8. My improved method of working and protecting guns is designed for
facilitating the use of the heaviest ordnance. It is composed of two parts,
which in practice will be conveniently employed in combination.. I construct
a platform of great solidity and strength capable of carrying the gun and its
carriage, as well as a gun shield built on the platform at one end and a
turntable upon it at the other end. The platform rests upon a pivot as its
centre, round which it traverses or revolves on wheels or rollers in the manner
of an ordinary gun platform. On the front. end of the platform I construct
an armour plated gun shield of the dimensions and strength required for the
gun to be worked and the projectiles to bo resisted. The lower part of this
shield is covered and protected by a fixed parapet up to the line of the bottom
of the embrasure of the shield, and its sides are covered and protected with
the fixed armour plated wall or structure behind which it is placed. In
training the gun horizontally, the shield being on the platform which carries
the gun, the embrasure turns with the muzzle protruding through it, and
therefore it may be of the same width as the muzzle. When the muzzle does
not project outside the embrasure the shield can be turned inwards, so that
the embrasure will be masked and protected by the armour plated wall or
structure which covers the shield on either side.
Two advantages may be obtained from this arrangement, the lateral range
may be greatly increased, and the gun as well as the gunners protected when
the gun is turned inwards. On the rear end of the platform I construct a
turntable which rests upon and traverses with the platform, and is so placed
and arranged thereon that the gun when fired, may, with its carriage, recoil
on to the turntable; or he afterwards drawn upon it. The gun may then be
turned round to a convenient position for loading: The moment after the
gun has been fired a quarter-circle turn, more or less, of the platform will
bring the embrasure inside the armour plated side defences of the shield.
The Diagrams Figs. 12, 13, 14, illustrate these improvements. Fig. 12 is a
front elevation of the gun shield; Fig. 13 is a side view, and Fig. 14 à plan,
of the gun platform with the shield and turntable upon it. (a, a,) is the
platform; (b, b,) the gun shield; (a, c,) the embrasure; (d, d,) the parapet;
:

page_text: (e, e,) the side defences, being part of the main structure; (f.f.) the turn-
table; (9,9,) the roof or deck of the main structure. The parts of this
improvement may be used separately or in combination, and they are, or
either of them is, applicable to forts, ships, or batteries, stationary or moveable.
The platform, instead of traversing on a pivot as shewn in the Drawing Fig. 13,
may be supported by rollers, or balls and sockets with universal joints, resting
on an incline, on which the platform with its superstructure and the gun
may recoil when the front of the shield is struct by projectiles.
Of the improvements herein-before described forming parts of my Invention,
those which relate to the construction or rifling of guns and projectiles are
respectively applicable to muzzle or breech-loading guns, or to solid or hollow
shot, those for the prevention of windage, described under numbers 2 and 3,
are applicable to sabots of wood, metal, or other material placed between the
gunpowder charge and the projectile. All the said improvements in rifling or
for the prevention of windage, are chiefly designed for great guns, but I intend
that any of such improvements or parts thereof as are applicable to shall be
used for small arms, and each of the aforesaid improvements, or of the parts
thereof, whether relating to guns or projectiles, or to gun carriages, platforms,
or shields, may be used separately, or in combination with all or any of the
other improvements or parts thereof respectively.
.
In the foregoing description of the application of my system of making the
grooves in the bore of a gun deeper on one side than on the other of the bore
I described that system in combination with the gravitating principle, which I
believe to be the right mode of applying it. But the said system may be carried
out by making the grooves in the manner aforesaid deeper and wider, on any
other part of the circumference of the bore of the gun than at the upper side,
the essential object of the plan, irrespective of the graviating principle, being to
prevent strain from the rifling of the projectile on opposite sides of the gun.
And although I have described my aforesaid plan of enlarging the grooves
on one side as applied to half the circumference of the bore, it may in some
cases be carried out in practice with advantage by applying the said plan to a
less or greater portion of the circumference of the bore than a half. These
explanations as to the grooves in the bore apply to the increase in diameter
of a part of the bore of the gun itself, as herein-before described. Such
increase in the depth of the grooves may be applied to any part of the cir-
cumference of the bore, and may be less or greater than half of the circum-
ference of the bore. With reference to the form of the rifled grooves or ribs
in the bore of the gun and the projectile, they may in some cases with straight
riding, or with a slow pitch in the case of spiral rifling, be of a different

page_text: section on opposite sides of the bore, but in such cases the rifling of the pro-
jectile must correspond with that of the bore."
Having ascertained by experiments the efficiency of my system of rifling in
;preventing strain on the gun or the projectile by making the grooves on one side
of the bore larger than the grooves on the opposite side of the bore, I find that
the cylinder or lands of the projectile under certain circumstances, may with
advantage fit closely into the cylinder or lands of the bore as a piston fits into
a steam cylinder allowing, no windage between the two cylinders or sets of
lands, and the required windage for loading reduced to a minimum, may be
obtained through the grooves of the rifling enlarged on one side of the gun
as herein-before described, thereby diminishing the loss of explosive gas in
firing the gun to a very small quantity.
:
"
The application of this plan is shewn in Diagram No. 4, in which the
enlarged grooves forming windage spaces are lettered (r). When these are
used for windage the air passage (m) through the projectile is not required.
By experiments with a rifle constructed on, my gravitation system it has been
demonstrated that for small arms the required amount of windage can be
obtained through the space of the enlarged grooves.
.:
Fig. 15 of the annexed Drawings is a longitudinal and transverse section of
my system of rifling applied to a rifle of about the same gauge as the military
arm termed an Enfield rifle, and shewing the cylinder of the bullet a mechanical
fit in the bore of the gun; (a) is the solid head of the bullet; (b) the hollow
space of the bullet filled with cement; (c) the ribs on the bullet, and tlie corre-
sponding lower grooves in the gun forming the rifling; (d) the upper grooves
in the bore slightly enlarged and affording windage space; (e) lubrication cup.
Having thus described my Invention and various moles of carrying into
effect the improvements which constitute the different parts thereof, I wish to
explain with reference to my first improvement; I do not claim any parti-
cular section or form, or dimensions, or number of ribs or grooves forming
the rifling of -guns or projectiles, such first improvement being applicable to
any kind of rifling, and I wish it to be understood that what I claim as my
Invention is,
.
1st. The principle of forming the rifling grooves in. the upper half of the
bore of a gun, or in the upper half of the bore itself, longer in radius- as
measured from the centre of the bore, or larger in diameter, than the grooves.
or bore at the lower half of the bore, and making the radii of the ribs on the
projectile or the diameter of the projectile precisely the same as the radius of
the grooves or of the cylinder at the lower half of the bore, whereby the axis
of the projectile and the-axis of the bore will be concentric, whether the pro-

page_text: jectile be stationary or in motion in the bore, and the projectile will travel in the
bore by gravitation, as described. under the head of improvement No. 1.
2nd. The same principle as applied at opposite sides of the bore to the
grooves or the bore at any part of the circumference of the bore, the object
of this mode of application being to prevent strain on opposite sides of the
without reference to gravitation.
gun
3rd. The mode of constructing hollow elongated projectiles so as to regulate
their equilibrium by filling the hollow space wholly or in part with any
material which, being applied in a plastic state either in the hollow space or
previously moulded to the form of such space, will set and harden, as described
under the head of improvement No. 1.
4th. The mode of preventing or diminishing the windage of guns in firing
by means of rings springs on the principle of the packing of a steam piston,
as described under the head of improvement No. 2.
5th. The mode of obviating the effects of windage by means of a com-
pressible or expanding disc or ring, as described under the head of improve-
ment No. 3.
6th. The plan of balancing and guiding projectiles in smooth bored guns
on ribs or points, or by means of grooves on the bore or the projectile, as
described under the head of improvement No. 4.
7th. The plan of constructing a spherical or elongated explosive projectile
in the manner described under the head of improvement No. 5.
8th. The mode of attaching false heads and ends to projectiles in the manner
and for the purposes as described under the head of improvement' No. 6.
9th. The mode of constructing gun-carriages and platforms, in combination
with turntables, for working guns, as described under the head of improve-
ment No. 7.
10th. The system of revolving gun shields and embrasures, as described
under the head of improvement No. 8.
And with reference as to each of the said improvements to the Drawings
hereunto annexed, in which they are repectively illustrated.
In witness whereof, I, the said George Clark, have hereunto set my
hand and seal, this Twenty-sixth day of January, in the year of our
Lord 1961
GEO. CLARK. (L.S.)