IMPROVEMENTS IN PROJECTILES
Year: 1856

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, and of 166, Buchanan Street, in the City of
Glasgow, North Britain, Gentleman, for the Invention of "IMPROVEMENTS
IN PROJECTILES."-A communication from Gaun M. Hutton, Citizen of
the United States, now acting as Vice-Consul for the United States at
St. Petersburg, in the Empire of Russia.
Sealed the 18th February 1857, and dated the 11th November 1856.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 11th November 1856.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North Britain,
Gentleman, do hereby declare the nature of the said Invention for "IMPROVE -
MENTS IN PROJECTILES," a communication from Gaun M. Hutton, Citizen of the
United States, now acting as Vice-Consul for the United States at St.
Petersburgh, in the Empire of Russia, to be as follows:-
pro-
This Invention relates to certain improved forms and constructions of
jectiles for fire-arms, and consists in constructing and arranging a spherical
shot, shell, hollow shot, shrapnels, or other spherical projectile, in such a
manner that when it is placed in the piece, ready for firing, its centre of

page_text: gravity will be directly in front of its centre of figure, and so that its axis of
gyration or rotation will coincide, or nearly coincide, with a line passing
through the centres of figure and gravity, such line also corresponding to the
axis of the piece. A motion of gyration or axial rotation is imparted to
the projectile by moderately inclined grooves in the piece through the
intervention of a " gromet" or ring of some sufficiently light, strong, and
yielding or compressible material, such as felt, pressed in behind the projectile
and the sides of the bore by the action of the discharge explosion.
In carrying out the Invention in the case of solid shot, a short cast in the
usual complete spherical form is floated in mercury. The lightest part of the
shot turns uppermost, and the shot being marked upon the bighest point as
it floats, a hole is bored into it at that point to near its centre, the hole being
of about one-fifth of the shot's diameter. This hole may be either cylindrical
or slightly conical, with the widest part at the surface. The hole is plugged
up firmly with wood, the sides being treated with white or red lead paint to
insure adhesion.*
Shot may be cast with the holes in them, but it is better to cast them solid,
as the process of floating them in mercury will ensure a more accurate balance.
The shot is placed in the piece with the plug behind, which position it
retains during the flight, the heaviest ends of the shot going foremost, whilst
the shot rotates about an axis coincident, or nearly so, with the axis of
the plug.
It is preferred to make the gromet of felt, and of such form as to easily fill
the space between the projectile and the side of the piece's bore, from a point
about square with the centre of the shot to a point about square with the
hinder part thereof, it not being necessary, however, to more than partially fill
the space between the back of the shot and the side of the piece. The gromet
may be greased, to diminish the friction upon the side of the bore, the grease
being applied directly to the surface of the gromet, or to a covering of linen,
cotton, or other suitable material pasted or glued upon it. Such covering may
be extended further forward than the centre of the shot, to more effectually
prevent contact of the shot with the sides of the bore. To secure the whole
together and to preserve the relativo positions, a light sabot of wood or other
suitable material is attached behind the projectile and gromet by means of
straps of thin metal or other suitable material.
Existing shells having an interior culot opposite to the fuse hole, may be
adapted to the improved system, if the edges of the fuse bale are sufficiently
strong to admit of a metal fuse plug being screwed into it, so as to prevent
the charge in the shell from being ignited when the shell is fired from the piece.

page_text: In making new shells, the internal space may be of a cylindrical or slightly
conical form, the narrower end being forward in the latter case. A sufficient
mass of metal is left in front of the internal space to throw the centre of
gravity in front of the centre of figure, and the axis of the internal space
coinciding with a line passing through these two centres the shell will rotate
on this axis, the heaviest part of the shell going foremost. The sabots for the
shell are made with a central hole of about one-fourth the calibre in diameter
in the direction of the axis, and when the sabots are of weod, it is preferred
to make them of the central parts of trees or branches, and to place them
with the grain of the wood running in the direction of the axis.
According to another modification, a spherical shot may be bored as if to
receive a plug, in the manner herein-before described, the hole, however, being.
made a little deeper and wider. The hole thus made is to be filled with fuse,
or similar composition, strongly compressed, leaving only space for a cap of
brass, steel, or iron, to be firmly screwed down upon it. In the cap a central
hole is made, of about one-fourth or one-fifth its diameter.
The com-
position will be ignited by the discharge, and the issuing gas will have a
propulsive and incendiary effect, and show the path of the shot at night.
For shells and hollow shot a percussive contrivance may be used, consisting
of a hollow piston or plug sliding with more or less friction in a tube, and
having on, its front end a nipple carrying a percussion cap, which will be
exploded by the shell striking the object, the piston forcing the cap violently
against the bottom of the tube. The passage of the flame through the piston
may be retarded by interposing mealed powder.
The herein-before described contrivances may be modified in various ways.
Thus, for example, the sabot and gromet may be united in one piece, and may
be all of wood, felt, or other suitable material, or the gromet may be so
far completed or made up behind as to dispense with an additional sabot.
The fuse hole of the shells or hollow shot may be made either in front or
behind, and the shot and shell may be used in either smooth bored or rifled
cannon. The solid shot may also be used without boring and plugging them,
their light side being ascertained by floating them in mercury, or otherwise,
and being marked so that the shot may be placed in the piece with the light
sido behind.

page_text: .
SPECIFICATION in pursuanco of the conditions of tho Letters Patent, filed
by the said John Henry Johnson in the Great. Seal Patent Office on
the 11th May 1857.
}
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex, an
of 166, Buchanan Street, in the City of Glasgow, North Britain, Gentleman,
send greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of November, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her
reign, did, for Herself, Iler heirs and successors, give and grant unto me,
the said John Henry Johnson, Her special license that I, the said John
Henry Johnson, my executors, administrators, and assigns, or such others as
I, the said John Henry Johnson, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, sliould 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 PROJECTILES," a communication from Gaun M. Hutton,
Citizen of the United States, now acting as Vice-Consul for the United States
at St. Petersburgh, in the Empire of Russia, upon the condition (amongst
others) that I, the said John Henry Johnson, by an instrument in writing
under my hand and seal, 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 John Henry Johnson, 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 accompanying Drawings, and to the
letters and figures marked thereon, that is to say -
The said Invention relates to certain improved forms and constructions of
projectiles for fire-arms, and consists in constructing and arranging a spherical
shot, shell, hollow shot, shrapnel, or other spherical projectile, in such a manner
that when it is placed in the piece ready for firing its centre of gravity will be
directly in front of its centre of figure, and so that its axis of gyration or
rotation will coincide or nearly coincide with a line passing through the

page_text: centres of figure and gravity, such line also corresponding to the axis of the
piece. A motion of gyration or axial rotation is imparted to the projectile by
moderately inclined grooves in the picce through the intervention of a
"gromet
or ring of some sufficiently light, strong, and yielding or com-
pressible material, such as felt, pressed in behind between the projectile and
the sides of the bore by the action of the discharge explosion.
In carrying out the Invention in the case of solid shot, a shot cast in the
usual complete spherical form is floated in mercury. The lightest part of the
shot turns uppermost, and the shot being marked upon the highest point as it
floats, a hole is bored into it at that point to near its centre, the hole being
about one-fifth of the shot's diameter. This hole may be either cylindrical or
slightly conical, with the widest part at the surface. The hole is plugged up
firmly with wood, the sides being treated with white or red lead paint, to
ensure adhesion.
Shot may be cast with the holes in them, but it is better to cast them solid,
as the process of floating them in mercury will insure a more accurate balance.
The shot is placed in the piece with the plug behind, which position it retains
during the flight, the heaviest end of the shot going foremost, whilst the shot
rotates about an axis coincident or nearly so with the axis of the plug.
It is preferred to make the gromet of felt, and of such form as to easily fill
the space between the projectile and the side of the piece's bore, from a point
about square with the centre of the shot to a point about square with the
hinder part thereof, it not being necessary, however, to more than partially
fill the space between the back of the shot and the side of the piece. The
gromet may be greased, to diminish the friction upon the side of the
bore, the grease being applied directly to the surface of the gromet, or to a
covering of linen, cotton, or other suitable material, pasted or glued úpon it.
Such covering may be extended further forward than the centre of the shot,
to more effectually prevent contact of the shot with the sides of the bore.
To secure the whole together, and to preserve the relative positions, a light
sabot of wood or other suitable material is attached behind the projectile
and gromet by means of straps of thin metal, or other suitable material.
Existing shells, have an interior culot opposite to the fuse hole, may be
adapted to the improved system if the edges of the fuse hole are sufliciently
strong to admit of a metal fuse plug being screwed into it, so as to prevent
the charge in the shell from being ignited when the shell is fired from the
piece.
In making new shells, the internal space may be of a cylindrical or
slightly conical form, the narrower end being forward in the latter case.

page_text: A sufficient mass of metal is left in front of the internal space, to throw
the centre of gravity in front of the centre of figure, and the axis of the in-
ternal space, coinciding with a line passing through these two centres, the
shell will rotate on this axis, the heaviest part of the shell going foremost.
The sabots for the shell are made with a central hole of about one-fourth
the calibre in diameter in the direction of the axis, and when the sabots are of
wood, it is preferred to make them of the central parts of trees or branches,
and to place them with the grain of the wood running in the direction of the
axis.
According to another modification a spherical shot may be bored as if to
receive a plug, in the manner herein before described, the hole, however, being
made a little deeper and wider. The hole thus made is to be filled with fuse
or similar composition, strongly compressed, leaving only space for a cap of
brass, steel, or iron, to be firmly screwed down upon it. In the cap a hole is
made, so that the composition being ignited by the discharge of the piece, the
issuing gas from the projectile will have a propulsive and incendiary effect, aud
will show the path of the shot at night.
For spherical shells and hollow shot of the construction herein-before
described, a percussive contrivance may be used, consisting of a hollow piston
or plug, sliding with more or less friction in a tube, and having on its front
end a nipple, carrying a percussion cap, which will be exploded by the shell
striking the object, the piston forcing the cap violently against the bottom of
the tube. The passage of the flame through the piston may be retarded by
interposing mealed powder.
The herein-before described contrivances may be modified in various ways.
Thus, for example, the sabot and gromet may be united in one piece, and may
be all of wood, felt, or other suitable material; or the gromet may be so far
completed or made up behind as to dispense with an additional sabot. The fuse
hole of the spherical shells or hollow shot may be made either in front or bebind,
and the shot and shell may be used in either smooth bored or rifled cannon.
The solid shot may also be used without boring and plugging them, their
light side being ascertained by floating them in mercury, or otherwise, and
being marked so that the shot may be placed in the piece with the light side
bebind.
And in order that the said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheet of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts throughout all the
corresponding Figures.

page_text: Figure 1 of my Drawings represents a section of a spherical solid shot,
constructed according to this Iuvention. A is the body of the shot, which is
bored on its lightest side to about its centre, this hole or bore being filled up
with the wooden plug B. It will be found advantageous to make the hole and
plug conical, that is, a little wider at the surface of the shot, and tapering
moderately inwards towards the centre. By coating the sides of the holes with
white or red lead paint, the wooden plugs will adhere sufficiently when driven
tightly home. By this mode of balancing the shot the position of the axis of
gyration will be preserved during the flight by the centrifugal force tending
to keep the centres or mean circle of the momentum of gyration at the greatest
possible distance from the axis; the resistance of the air at the same time
maintaining the axis parallel to the path described by keeping the lighter
side of the projectile behind.
New shot may have the holo or cavity cast in them, but it is found more
advantageous to cast them solid, and then proceed to find the lighter side by
ficating them in mercury, as herein-before described.
A spherical projectile, so balanced and placed in the piece, requires to
receive only a moderate velocity of gyration, which will not endanger the com-
maud or control of the gromet over it by the simple hold or grip of friction.
That risk I still further diminish by using what is termed a moderately gaining
twist, tho pitch of the twist or screw gradually increasing towards the muzzle.
A final pitch at the muzzle of one turn in about two hundred and fifty calibres
for light charges gives a good result, and one in three hundred calibres for
strong charges.
I prefer to make the gromet shewn at C (Figure 1, and in detail section
and plan detached at Figures 2 and 3) of felt, and of such a form as to fill
easily the space between the projectile and the bore of the piece, at a point
about square with the centre of the projectile, and extending back along the
bore of the piece to about square with the hinder part of the shot, as shewn
by the dotted lines c, c, in Figure 1, the hinder portion of the gromet being
tapered or bevilled inwards, as shewn clearly at d, d, in Figure 2.
I grease the outer or cylindrical part of the gromet, to reduce friction,
which may be still further reduced by making the gromet rather smaller than
the bore, and attaching by any suitable cement a covering of linen or other
fabric, which should be then well greased. Such covering may extend further
forward than square with the centre of the shot, in order the more effectually
to prevent contact of the projectile with the bore.
To secure the whole together and preserve the proper positions, I attach a
light sabot D (Figure 1), of wood or other suitable material, behind the pro-

page_text: .jectile, the front end of the sabot being tapered to enter the conical recess d, d, in
the back of the gromet, as shewn at Figure 1, the sabot being secured
thereto by the straps E, E, of thin tin; copper, or other suitable material.
I mako a central hole in the sabot employed with my projectiles, as shewn
in Figure 1, such hole being in the direction of the axis of the sabot, and of
about one-fourth the calibre in diameter, and when these sabots are of wood I
prefer to make them of the central parts of trees or branches, and to place
the grain of the wood in the direction of the axis of the sabot.
Another good arrangement for shot is, to make the hole which is bored
therein a little deeper and wider than before stated, and to fill this hole with
fuse composition, strongly compressed, leaving only space for a cap of brass,
steel, or iron, to be firmly screwed down upon it. A hole or holes is or are
made through this cap, so that the composition being ignited by the discharge
of the piece, the issuing flame or gas from the projectile will have a propulsive
and incendiary effect, and will show the path of the shot at night. A shot of 1
this description is shewn in section at Figure 4, and the metal cap is repre-
sented detached in plan and elevation at Figures 5 and 6 respectively.
A is the body of the shot; B, the hole bored therein on the lightest side;
C, the metal cap, which is screwed into the hole B, and is perforated at c, c.
Existing shells, having an interior culot opposite to the fuse hole, may be s
adapted to my system, if the fuse hole be sufficiently strong to admit of a metal
fuse plug being screwed therein, so as to prevent the charge in the shell from
being ignited when the shell is fired from the piece.
For new shells, I not only diminish the otherwise spherical hollow space by
the addition of the culot, but I also contract that side of the cavity or hollow s
space, so as to cause it to assume the form of a hollow cylinder or portion of a
cone: A shell of this description, fitted with an internal culot, is represented in
vertical section at Figure 7.
A is the body of the shell; B, B, the contraction of the internal cavity, for
the purpose of increasing the weight of the front part of the projectile. The
centre of gravity will thus be thrown in front of the centre of figure, and the
axis of greatest momentum of gyration will be made to pass with sufficient
exactness through both those centres, in which position the centrifugal force
will tend to retain it during the flight.
For spherical shells and hollow shot of my peculiar construction a percussion
arrangement may be easily combined, consisting of a hollow or perforated
piston or plug C (Figure 7), sliding with more or less friction in a tube D, and
having on its front end a nipple c, carrying a percussion cap, which cap will
be exploded by the shell striking the object, since the piston will then force

page_text: the cap violently against the bottom of the tube, or whatever obstacle may bo
in its front. As the piston is made to work air-tight in its tube, the air in
the front of the tube acts as a spring or cushion, and with the friction prevents
the cap from touching the bottom, except when the shell meets with great
resistance. The heat of the suddenly compressed air might also be used
to ignite an inclosed priming of powder, independantly of the cap. The
passage of the flame through the piston from the cap may be retarded by
interposing or placing mealed powder inside the perforation or passage;
through the piston shewn by dotted lines in Figure 7.
Reverting to the gromet, herein-before described in relation to Figures 1, 2,
and 3, I may observe that its proper density and hardness will be proportioned
to the windage and the charge, in order to secure the required action of the
grooves, and to prevent it being blown through. Tho gromet and sabot may
be inserted in one piece, and made of the same or different materials. The
gromet may be so far completed behind, or so formed at that part as to
dispense with anything in the nature of a sabot. The shot may be used, but
with less benefit, without having a hole or cavity made in the lighter side, and
the improved projectiles generally, herein-before described, may be used in
smooth-bored pieces with much benefit.
I may bere observe, that I prefer to use for my projectiles a stronger and
less brittle material than ordinary cast iron, such as Stirling's toughened cast
iron, and the compounds intermediate between steel and iron.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of the said Invention; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,-
First, the general constructions and arrangements of spherical projectiles, as
herein-before described.
Second, the system or mode of finding the lighter side of solid or hollow
spherical projectiles by floating them in mercury and marking the upper
surface.
Third, the constructing and arranging solid or hollow spherical projectiles
in such a manner that their centre of gravity when placed in the piece ready
for firing will be directly in front of their centre of figure, for the purpose
herein-before described.

page_text: Fourth, the boring out or chambering of the lighter side of solid spherical
projectiles, and the insertion or not of a wooden or other plug therein for the
purpose herein-before described.
Fifth, the filling of a chamber formed in the lighter side of a solid spherical
projectile with fuso composition, and the application thereto of a perforated
screwed metal cap, for the purpose herein-before described.
Sixth, the peculiar construction and arrangement of ring or "gromet," and
sabot, and their combination with a spherical projectile, in the manner and for
the purpose herein-before described.
Seventh, the contraction of one side of the inner cavity of spherical shells
or hollow shot, in such a manner that their centre of gravity when placed in
the pieco ready for firing shall be directly in front of their centre of figure, for
the purpose herein-before described.
Eighth, the application and use to and in shells of my peculiar construction
of the percussion apparatus described in referenco to Figure 7 of the
Drawings.
In witness whereof, I, the said John Henry Johnson, have hereunto set
my
hand and seal, the Eighth day of May, One thousand eight hundred
and fifty-seven.
J. HENRY JOHNSON. (L.S.)