IMPROVEMENTS IN THE CONSTRUCTION OF ORDNANCE, AND IN THE MODE OF PROPELLING PROJECTILES, AND ALSO IN THE CARTRIDGES AND ANNUNITION USED FOR THAT PURPOSE
Year: 1870

page_text: LETTERS PATENT to Henry Bessemer, of Denmark Hill, Dulwich, in
the County of Surrey, for the Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF ORDNANCE, AND IN THE MODE OF PROPELLING PROJECTILES,
AND ALSO IN THE CARTRIDGES AND ANNUNITION USED FOR THAT PURPOSE.”
Sealed the 28th February 1871, and dated the 29th November 1870.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at
the Office of the Commissioners of Patents, with his Petition, on
the 29th November 1870.
I, HENRY BESSEMER, of Denmark Hill, Dulwich, in the County of
3 Surrey, do hereby declare the nature of the said Invention for "Im.
PROVEMENTS IN THE CONSTRUCTION OF ORDNANCE, AND IN THE MODE OF PROPELLING
PROJECTILES, AND ALSO IN THE CARTRIDGES AND AMMUNITION USED FOR THAT
PURPOSE," to be as follows:-
In the largest description of rifled ordnance designed to throw
elongated projectiles against armour-plated vessels the immense power
generated by the sudden explosion of a large charge of gunpowder is
found to exert such a powerful disruptive force at the breech end of the
gun that it has been deemed necessary to employ a thickness of metal

page_text: at that part about equal to the diameter of the bore, even in those
cases where several coiled iron or steel cylinders are shrunk on onc over
the other. The heavy weight of metal required to construct guns having
these proportions tends greatly to limit the size to which such ordnance
can be constructed so as to become safe and practically useful; it will
also be observed that the reduction of pressure which takes place as the
gaseous matters expand and follow the projectile along the chase of the
gun gives a final pressure on the shot very greatly below that of the
first violent effort, I therefore consider it very desirable that a greatly
diminished and more equal pressure on the projectile should be main-1
tained throughout its whole passage along the chase of the gun, and
thus without the ultimate amount of force exerted upon it being dimi-
nished to avoid the excessive strain caused by the instantaneous explosion
of a large mass of powder.
It also appears desirable that projectiles of several tons in weight should
be employed, even if their velocity were not so high as is attained
by smaller projectiles with modern rifled ordnance, so that the vis
inertia of the massive armour plates may be overcome and the sides of the
vessel crushed in, instead of merely piercing a comparatively small hole
in the armour plates by the high velocity of a light projectile.
=
.
Now therefore the primary object sought to be obtained by my
Invention is the employment of ordnance in which there is a continued
formation of gaseous matters which exert a comparatively low and
equal pressure during the whole time that the projectile is traversing a
gun of very much greater length than those now in use. Thus, for
example, if we assume that a given charge of gunpowder would exert at
the moment of explosion a force of sixty thousand pounds on every
square inch of the interior of the chase of the gun exposed to its action,
and that by the time the shot has travelled along a chase of ten feet in.
length its pressure has been so greatly diminished as to be equal only
to a mean pressure of fifteen thousand pounds per square inch through-
out the entire length of the chase, I propose to employ in lieu of this
violent and rapidly diminishing force a continuous and nearly equal
force amounting only to about three thousand pounds pressure on the
square inch and to maintain this pressure on the shot throughout its
passage along a chase of fifty feet in length, thus obtaining an equivalent
amount of duty with a bursting strain of only one-twentieth the amount
of that produced by the sudden explosion of the whole charge before

page_text: referred to. When guns have to be subjected to pressures varying
from two to five thousand pounds per square inch only, a great variety
of modes of construction are admissable that would not be so for ordinary
heavy rifled ordnance, thus we may employ comparatively thin tubes of
gun metal, stero-metal, cast iron, steel, or mixtures of steel and cast iron;
wrought iron or forged steel, in each case, by preference, hooped with
wrought iron or steel hoops shrunk on and united in lengths of ten feet
by flanges and bolts, or these low-pressure guns may be formed by
bending a thin armour plate or a steel plate into a tube and welding or
riviting up the joint, and after it has been turned and bored shrinking
on to it a series of iron or steel hoops and end flanges for the purpose
of joining up the several lengths into one long gun. The breach may
be secured by a breach plug screwed into the end of the tube and kept
gas-tight by an expanding metal or other clastic cup or by forming a
knife edge on the plug to be forced against a ring of copper or other
soft metal let into a groove formed around the breach for that purpose.
In order that a continuous supply of gas under pressure may be generated
and act on the "projectile as it moves forward in its long tube, I make
a cártridge or powder chamber which fits loosely the inside of the gun;
may consist of a cylindrical mass of steel in which a great many
round holes have been drilled parallel to the axis of the cylinder and,
so near to each other as to form a series of separate cells, in number
from twenty to one hundred, and of two to five inches in diameter, more
or less, according to the size of the gun, the holes being so placed as
to leave a strong wall between them, each cell forming a kind of small
gun separate from the neighbouring cells, they are, to be filled with
gunpowder or other composition of a more or less explosive character.
In some cases I employ a rapidly burning rocket composition, the
charge in each cell being in that case bored up to give a greater surface
and thus increase the rapidity of its action; or I employ, by preference,
in each cell several charges of gunpowder separated from each other by a
diaphragm having a fusee for communicating between one charge and
another or having in lieu thereof a layer of meal powder or other slow
burning compound between each charge of gunpowder, the quantities
of powder increasing at every discharge, and the time of discharging.
each portion in a cell diminishing so as to keep time with the increasing
velocity of the projectile, and thus keep up the pressure in its rear
as nearly equal as may be throughout its entire movement from the
breach to the muzzle of the gun.
it

page_text: It will be understood that in each case the powder will be ignited at
the mouth of each cell and gradually burn down to the bottom of it,
or each cell may be filled with gunpowder and be fired one at a time
by time fusees, so regulated as to discharge one cell, say for every foot
in advance made by the shot, or the cells may be fired by galvanism, the
spark being communicated to cach cell by the contact of the shot against
insulated knobs passing through the sides of the gun at regular distances.
The powder or other material may be well pressed into the several tubes
of the cartridge (or into paper or other cases fitted into the metal cells)
by hydraulic force or otherwise, and the end of all tho tubes or holes
may be covered over with a soft metal capsule to render the whole
water-tight; and although I greatly prefer to employ the metallic
cellular cartridge, it will nevertheless be understood that meal powder,
compressed or otherwise, or powder mixed with extraneous substances
so as to render it extremely slow burning or non-explosive, or made into
balls or masses by admixture with resinous or other matters may be
employed in bags or canisters in carrying out my Invention, provided
that the combustion thereof be sufficiently gradual to last during the
traverse of the shot along the greater part of the chase of the gun, but
I believe the cellular mode will be found best adapted to secure regular
and safe results.
I would observe that the cellular chamber may be made by boring
a solid steel, cast-iron, or wrought-iron cylinder, or by casting it in gun
metal, steel, or malleable cast iron, or it may be formed of a cluster of
drawn tubes, cylindrical or hexagonal in section.
When it is desired to employ elongated projectiles in low-pressure
guns, I either use grooves for the purpose of giving rotation to the
projectiles, or I insert part of the charge in the rear of the projectile or
in a chamber attached thereto, and from which the gaseous matters issue
in a direction of a tangent to its circumference, and thus cause it to
rotate.
Guns constructed on this principal I propose to distinguish as the

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Bessemer in the Great Seal Patent Office
on the 29th May 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Denmark Hill, Dulwich, in the County of Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of November, in the
year of our Lord One thousand eight hundred and seventy, in the
thirty-fourth year of Her reign, did for Herself, Her heirs and suc-
'cessors, give and grant unto me, the said Henry Bessemer, Her special
license that I, the said Henry Bessemer, my executors, administrators,
and assigns, or such others as I, the said Henry Bessemer, my exe-
cutors, 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 "IMPROVE◄
HENTS IN THE CONSTRUCTION OF ORDNANCE, AND IN THE MODE OF PROPELLING
PROJECTILES, AND ALSO IN THE CARTRIDGES AND AMMUNITION USED FOR THAT
PURPOSE," upon the condition (amongst others) that I, the said Henry
Bessemer, 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.
NÓW KNOW YE, that I, the said Henry Bessemer, do hereby declaré
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 thereof, that is to say :—
I
In the largest description of rifled ordnance designed to throw elongated'
projectiles against armour-plated vessels, the immense power generated
by the sudden explosion of a large charge of gunpowder is found to
exert such a powerful disruptive force at the breech end of the gun, that
it has been deemed necessary to employ a thickness of metal at that part
about equal to the diameter of the bore, even in those cases where

page_text: several coiled iron or steel cylinders are shrunk on one over the other.
The great weight of metal required to construct guns having these
proportions tends greatly to limit the size to which such ordnance can
be constructed so as to be safe and practically useful. It will also be
observed that the reduction of pressure which take place as the gaseous
matters expand, and follow the projectile along the chase of the gun,
gives a final pressure on the shot very greatly below that of the first
violent effort; I therefore consider it very desirable that a greatly
diminished and more equal pressure on the projectile should be maintained
throughout its whole passage along the chase of the gun, and thus
without the ultimate amount of force exerted upon it being diminished
to avoid the excessive strain caused by the instantaneous explosion of a
large mass of powder.
It also appears desirable that projectiles of several tons in weight
should be employed, even if their velocity were not so high as is attained
by smaller projectiles with modern rifled ordnance, so that the vis inertia
of massive armour plates may be overcome, and the sides of vessels
crushed in, instead of merely being pierced with a comparatively small
hole through the armour plates by a light projectile moving at a high,
velocity.
Now therefore the primary object sought to be obtained by my.
Invention is the employment of ordnance in which there is a continued
or repeated formation of gaseous matters which exert a comparatively
low and equal pressuro during the whole time that the projectile is
traversing a gun of very much greater length than those now in use.
Thus, for example, if we assume that a given charge of gunpowder would
exert at the moment of explosion a force of sixty thousand lbs. on every.
square inch of the interior of the chase of the gun exposed to its action, and
that by the time the shot has travelled along a chase of ten feet in length
its pressure has been so greatly diminished as to be equal only to a mean ;
pressure of fifteen thousand lbs. per square inch throughout the entire
length of the chase. I propose to employ in lieu of this violent and
rapidly diminishing force, a continuous and nearly equal force, amount-
ing only to about three thousand lbs. pressure on the square' inch, and
to maintain this pressure on the shot thoughout its passage along a
chase of fifty feet in length, thus obtaining an equivalent amount of duty.
with a bursting strain of only one-twentieth the amount of that produced
by the sudden explosion of the whole charge before referred to.
-

page_text: It will be understood that the gaseous pressure and the length of the
chase of the gun here given are merely used as examples illustrative
of the general principles on which my Invention is based.
When guns have to be subjected to pressure, varying from two to five
thousand pounds per square inch only, a great variety of modes of
construction are admissible that would not be so for ordinary heavy
rifled ordnance; thus we may employ comparatively thin tubes of gun
metal, stero-metal, cast iron, steel, or mixtures of steel and cast iron,
wrought iron or forged steel, in each case by preference hooped with
wrought iron or steel hoops, shrunk on to the inner tube, which may be
in lengths, often feet more or less, such lengths being connected by
'bolts and flanges on the hoops at their extremities; or these low-pressure
guns may be formed by bending a thin iron armour plate or a steel
plate into a tube, and welding or rivetting up the joint, and after it has.
been turned and bored shrinking on to it a series of iron or steel hoops
and end flanges, for the purpose of joining up the several lengths into
one long gun.
In order that this mode of constructing guns may be fully understood
I have hereunto annexed a Sheet of Drawings, on which a gun so con-
>structed is shewn in clevation at Figure 1, and part of the same is
shown in, longitudinal section in Figure 2, and in cross section at
Figure 3. ...
3..
-
a is the inner tubo which may consist as before named of several
thick plates of iron, each bent into a tube and welded along the line
5-where their edges meet, the parts of the tube are bored truly on their
interior surfaces to the required diameter, and their external surfaces are
also turned truly in order to receive a séries of steel hoops b-bored to
-the required size, and put on hot so as to embrace the inner tube with
a considerable pressure by their contractile force in cooling; c; c,
O are flanged hoops screwed on to the ends of the inner tube a, for the
purpose of connecting the several lengths of the chase by means of
steel bolts & passing through the flanges. The breech of the gun may
be secured by a movable breech plug screwed into the end of the tube,
and kept gas-tight by an expanding metal or other elastic cup, or by
5 forming a knife edge on the plug to be forced against a ring of copper
or other soft metal' let into a groove formed around the breech for that
purpose. This breech picce is shewn at e, Figure 2, having a knife or
chisel-shaped edge formed around it, which comes in contact with a

page_text: ring of copper f retained in place by a dovetailed angle formed within
the bore as shown. The removal of the breech piece is effected by a
stout rod g fastened into the rear of the breech piece and supported in
a sling or bearing / suspended from a small jib crane (not shewn), a
counterbalance i is fitted on the opposite end of the rod 7 having handles
for the purpose of turning round the breech piece. The weight i is
keyed on loosely so as to have freedom of motion for about one-cighth
part of a revolution, and may be thus made to act percussively both in
tightoning and loosening the breech screw. In order that a continuous
supply of gas under pressure may be generated, and act on the pro-
jectile as it moves forward in its long tube I make a cartridge or powder
chamber which fits loosely the inside of the gun, it may consist of a
cylindrical mass of steel in which a great many round holes have been
drilled parallel to the axis of the cylinder, and so near to each other as
to form a series of separate cells in number, say from twenty to one
hundred and of two to five inches in diameter more or less according to
the size of the gun. These holes are so placed as to leave strong walls
between them, each cell forming a kind of small gun separate from the
neighboring cells. They are to be filled with gunpowder or other com-
position of a more or less explosive character. In some cases I employ
a rapidly burning rocket composition the charge in each cell being in
that case bored up to give a greater surface, and thus increase the rapidity
of its action; or I employ by preference in each cell several charges of
gunpowder, each separated from the other by a diaphragm having a fuzee
for communicating between one charge and another, or in lieu thereof
by a layer of meal powder or other slow burning compound. The
quantities of powder in these charges increase at every succeeding
discharge of the series, and the intervals of time between the discharges
diminish so as to keep time with the increasing velocity of the pro-
jcctile, and thus keep up the pressure in its rear as nearly equal as may
be throughout its entire movement from the breech to the muzzle of
the gun. The steel or other metal cartridge or powder chamber is
shewn inside the gun at m, in Figure 2, and in end elevation at Figuro 4;
n are the separate cells containing the gunpowder, which is separated
into different charges by diaphragms or wads each having a hole in the
centre. The powder in each such hole forms an extremely short fuzee
and thus the charges are fired in rapid succession. At j is a percussion
cap and small charge of powder contained in a separate piece o screwed
into the central part of the cartridge, and behind the cap; a small

page_text: steel rod k is fitted so as to be moved with a small amount of force. In
a line with this rod is a similar rod passing through the rod g, so
that on receiving a blow on its outer end l it comes in contact with
the rod k, and forces the latter against the percussion cap and explodes
the charge of powder in o, thus igniting the powder at the open ends
of the several cells of m. These cells are secured from injury and aro
kept dry by a capsule of pewter or other soft metal p, which covers the
entire surface of the cartridge, overlapping its edge where it is forced
into small threads or corrugations formed around the exterior surface
of the cartridge and is thus firmly held in place. In the rear of the
cartridge a projecting part me is formed having a screw thread in it for
the purpose of attaching to it a rod used to withdraw the cartridge
from the gun after it has been discharged.
In Figure. 2 I have shewn a nearly spherical shot for a gun of
twenty-four-inch bore, the spherical surface would be about twenty-six
inches in diameter and be reduced to twenty-four inches by forming on it
a flat band or zone r* of a size to fit the gun like a piston. A shot so
formed may have less windage than a spherical shot, and will not like
a spherical shot be set into rapid rotation during its passage along the
chase of the gun. The flight of such a shot will in consequence be more
accurate than that of spherical shot. Projectiles of other forms may
nevertheless be used if preferred.
"
:
In the arrangement already explained the powder is ignited at the
mouth of each cell and gradually burns down to the bottom of it. The
cells may, however, be filled with gunpowder and be fired one at a
time, fuzces so regulated as to discharge one cell say for every foot in
advance made by the shot. The several cells in this case may be madė
to communicate with a central fuzee, the communications from the fuzee
to the cell being so timed as to discharge the cells in succession and at
such intervals as to generate as near as may be practicable a quantity of
gas corresponding to the advance made by the projectile along the chase
of the gun. Or the cells may be fired by galvanism, the spark being
communicated to each cell by the contact of the shot against insulated
wires or knobs passing through the sides of the gun at regular distances.
The powder or other material may be well pressed into the several tubes
or cells of the cartridge (or into paper or other cases fitted into the metal
cells) by hydraulic force or otherwise, and the ends of all the tubes or

page_text: 8
cells
may be covered over with soft metal capsules to render the whole
water-tight. This mode of igniting separate charges of powder at
regulated intervals as the projectile moves forward along the chase of
the gun is illustrated at Figure 5, where the cartridge or powder
chamber a is made to serve also as the moveable breech of the gun, and
is retained in place by the screw threads t which may remain entire or
may be in part cut away both on the interior of the gun and on the
breech piece, so that the latter may be pushed in and by a portion only
of one turn may be firmly held in place in a manner well understood.
I have shewn in Figure 5 an elongated projectile u, although other
forms of shot or shell may be employed. At short intervals along the
chase of the gun small holes are drilled in pairs, into which insulated
wires or rods varo fitted. The openings externally and internally are
provided with small non-conducting screwed caps to retain the insulating
material in place, the ends of the wires or rods being of such length that
the projectilo in passing over them will touch them sufficiently to
produce metalic contact and establish electrical communication between
each pair of wires as the projectile moves along. Each of the cells of
the. cartridge is provided with one of Abel's fuzees or other similar
fuzees, as shewn at w, the wires from which pass through the end of the
cartridge at x and are to be in connection with a battery and with the
wires v, so that whenever the projectile u comes in contact with a vair
of wires a charge of powder contained in one of the cells of the
cartridge will be immediately ignited, and so on until all the cells are
discharged. Thus if a pressure of, say, 3,000 lbs. por square inch is
intended to be employed, and the pairs of wires are placed, say, 1 foot
apart along the chase of the gun, then as much powder must be placed
in cach cell as will by its conversion into vapour produce the desired
pressure in a space equal to one foot in length of the bore of the gun,
and thus a continuous and comparatively uniform pressure will be
exerted throughout the entire passage of the projectile alone the chase
of the gun, which may be from 50 to 60 feet in length, or even much
longer when used in gunboats specially designed for such guns. By
this means a high initial velocity may be given to projectiles of great
weight by the employment of pressures so low that the construction of
such guns may be much simplified without risk of the gun bursting.
The mode of mounting the gun may be on carriages as usual or by
simply fixing the gun lengthwise in a boat at a slight elevation and firing

page_text: it when the movement of the vessel brings it to the desired elevation and
direction.
I would observe that the cellular cartridge or charge chamber may bò
made by boring a solid steel, cast iron, or wrought iron cylinder, or by
casting it in gun metal, steel, or malleable cast iron, or it may be formed
of a cluster of drawn tubes cylindrical or hexagonal in section...
When it is desired to employ elongated projectiles in low-pressure
guns I either use grooves for the purpose of giving rotation to the
projectiles, or I insert part of the charge in the rear of the projectilo or
in a chamber attached thereto. The gaseous matters issue from the
projectile in a direction at a tangent to its circumference, and thus
cause it to rotate.
=
The rotation of elongated projectiles by the emission of a portion of
the gaseous matters resulting from the charge of powder used to propel
the shot has been before used by myself and others to produce rotation;
such emission has, however, taken place in front of the shot. By my
present. Invention a separate charge or charges of powder are to be
contained in the projectile itself with openings placed at a tangent to its
circumference in the rear of the shot, and so that the gaseous matter
emitted therefrom whilst the shot is still in the bore of the piece may
add to the impelling power by which the projectile is thrown. Ordinary
gunpowder may be used for this purpose, or meal powder may be firmly
rammed in and afterwards be bored up into a hollow cylinder, as in
rockets, and in order that very rapid combustion may be obtained so.
that the whole may be consumed whilst the shot is in the gun I prefer
that the hole bored up should be so large in diameter as to leave but a
comparatively thin shell of powder to burn away, so that a very violent
action be obtained for a short interval only in lieu of a more con-
tinuous action, as in rockets. The great strength of the projectile as
compared with a rocket case will allow of smaller escape orifices, and
thus a very high pressure may be maintained within the projectile so
that the emissive force may be such as to give rapid rotation to the
projectile before it leaves the gun. A projectile so arranged is shewn in
Figures 6, 7, and 8, and in the longitudinal section in Figure 5. shews
the projectile; B, the cylinder of rammed powder; and O, the orifices
for the escape of gas which communicate with the interior by cored
passages _ *. shewn by dots. D is a plug screwed in the rear of the
may

page_text: projectile after it is charged. A central holes containing some fuzee
composition communicates the flame to the interior as soon as the first.
charge is fired to propel the shot.
An end elevation is shewn at Figure 7. The lines at E indicate the
direction of the emitted gases.
Figure 6 shews an end view partly in section of the projectile, and
Figure 8 is a side elevation.
•
. It will be observed that projectiles made to rotate by the emission of
gases from the rear of the projectile arc specially adapted to guns con-
structed and worked in the manner herein described with a moderate 1
pressure behind the projectile. I propose to call my system the "con-
tinuous low-pressure system."
.
Having thus described, my Invention, and the manner in which the
same may be carried into operation; I desire. it to be understood that I
do not confine myself to the precise details herein described, provided' 1
that the general character of my Invention be retained; but what I do
claim is,―
First. The adaptation at the breech end of the gun of a steel or other
metal cartridge or charge chamber divided into cells so as to separato
the charge used to propel the projectile into portions which operate in 2
succession on the projectile as it passes along the bore of the piece.
Second. Dividing the charge into parts by diaphragms or layers of less
rapidly burning material, so that the portions of thé charge may operate
in succession upon the projectile as it passes along the bore of the
piece.
Third. The adaptation of a time fuse to ignite in succession portions
of a charge contained in several cells, so that the portions of the charge
may operate in succession on the projectile as it passes along the bore of
the piece.
Fourth. Arranging the charge employed to propel the projectile in 30
separate cells and adapting apparatus in connection therewith to ignite
these separate portions of the charge by electricity during the passage of
the projectile along the bore of the gun, so that the portions of the
charge may operate in succession upon the projectile.
Fifth. The construction of projectiles in such manner that during their 3
passage along the boro of the gun they are caused to rotate by the emission.

page_text: from their rear ends of the gaseous products from a charge which the
projection carries.
In witness whereof, I, the said Henry Bessemer, have hereunto
set my hand and seal, this Twenty-seventh day of May, in the
year of our Lord One thousand eight hundred and seventy-one.