IMPROVEMENTS IN ORDNANCE AND PROJECTILES
Year: 1871

page_text: LETTERS PATENT to Henry Bessemer, of Denmark Hill, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN ORDNANCE
AND PROJECTILES."
Sealed the 28th July 1871, and dated the 1st June 1871.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at
the Office of the Commissioners of Patents, with his Petition, on
the 1st June 1871.
I, HENRY BESSEMER, of Denmark Hill, in the County of Surrey,
do hereby declare the nature of the said Invention for “IMPROVEMENTS
IN ORDNANCE AND PROJECTILES," to be as follows :—
My present Invention relates to improvements in the class of guns
and mortars in which the projectile is propelled by a succession of
separate discharges of gunpowder or other explosive material as it moves
along the chase of a gun or mortar of unusual length. For ordnance

page_text: of this class Letters Patent were granted to me bearing date the 29th
day of November 1870, and numbered 3130.
Now my present Invention consists in modifications and details of
construction and improvements in carrying into practical operation this
continuous low pressure system of ordnance, and which I will now 5
proceed to describe :-
In building up guns or mortars composed of two or more cylinders
placed end to end I employ flanged hoops, in the interior of which a
number of concentric grooves are turned. A similar series of grooves
are formed on those parts of the cylinders where these flanged hoops 1
are to be shrunk or forced on. I make suitable holes or channels in
these hoops, through which I pour fluid iron or other metal or alloy
into the annular cavities thus formed. The iron or other metal when
solidified forms a series of keys or feathers which effectually prevent
the removal of the hoop from the cylinder. In like manner I secure 1
the trunnion ring breech or other cylinders or hoops employed in built
up guns. A bard alloy of copper, tin, and bismuth is well suited for
use for this purpose, the latter metal lessens or prevents the shrinking
of the alloy in cooling. In some cases I mount the gun without
trunnions on a carriage or slide, and in that case I employ one or more 2
hydraulic cylinders to lessen the recoil and so arranged that the move-
ment of the gun cannot take place without discharging water under
the regulated pressure of a spring loaded valve. I also employ the
same hydraulic cylinders for moving the gun again into its position after
its recoil. I also make use of the motion of the gun for the purpose of
loading it, and for removing the breech and cartridge after it has been
discharged. I mount the breech plug or cartridge and the projectile
on a suitably constructed carriage or truck, and I bring it into such a
position on a rail or turntable at the rear of the gun so that by the
agency of the hydraulic cylinders the open end of the breech of the gun
may be made to slide over the projectile and breech piece which are
kept stationary during this movement. Several such loaded cartridges
and projectiles may be arranged on their respective carriages in position
to load the gun rapidly; the carriage after the discharge receiving the
emply cartridges and breech piece and conveying them away. A small
donkey pump driven by steam and provided with an accumulator or
air vessel will supply water under the desired pressure to operate in the
hydraulic cylinders and movo the gun.

page_text: In cases where the gun is fixed lengthwise in a boat, and has no
provision made for its recoil, an hydraulic apparatus may be also
employed to load the gun by the movement of a plunger, several
trucks supporting a projectile and breech piece being mounted on a
5 rail or turntable provided for that purpose. The pointing of the gun
in this case is managed by the movement of the vessel.
When guns of great length are employed on forts or otherwise on
land I prefer to mount them on two pairs of trunnions; these trunnions
rest on small wheels or slides, the supports of which are capable of
rising and falling so as to alter the clevation of the gun. This move-
ment may be given by inclined surfaces sliding over each other or by
hydraulic apparatus or screws driven by suitable gearing.
When the ignition of the several portions of the charge is to be
effected by electricity at intervals as the projectile advances along the
chase of the gun I bore small holes at one foot or other suitable distance
apart along the chase of the gun, such holes being in a radial direction
to the axis of the gun and in one or more rows. I fit a steel rod into
each hole and I pack the rods gas-tight with soft metal shavings or Icaf
metal. The ends of the rods are inclined or wedge-shaped and project
so far into the bore of the gun as to be moved about one-eighth of an
inch by the passage of the projectile along the chase of the gun. The
outer ends of the rods push forward wires or connecting pieces so as
to establish electrical communication between a battery and the fusces
contained in the cells of the cartridge or powder chamber, and thus
explode the charges, each rod having its appropriate wires of commu-
nication so as to ignite the numerous portions of the charge in succession
as the projectile advances along the chase of the gun.
Instead of allowing the ends of the rods to project into the bore of
the gun and be forced outwards by contact with the projectile, they may
be made so short as not to quite reach the interior of the gun, and be
actuated by the pressure of the gases acting on the end of the rods, or
in lieu of employing the rods for this purpose the emission of a portion
of the gases through very small holes may be made to force the wires
or other connecting pieces in contact, and thus establish electrical
communication. In either case I prefer to connect the wires from each
point to a ring or hoop mounted on a hinged joint, each wire being in
communication with a brass knob or connecting piece embedded in

page_text: gutta percha or otherwise insulated, a similar arrangement of wires
leading to the fusees contained in the several charges. On the exterior
of the breech piece another scries of connecting pieces arranged in a
ring are also insulated, the connecting pieces in which are so arranged
that on moving the first-named ring on its hinged joint the two scries
of wires become at once connected to one side of the battery, so that
as each rod in the side of the gun is moved outwards the circuit is made
complete and each cell of the cartridge is successively discharged.
When this system of successive discharges is applied to muzzle-
loading guns or mortars, the breech end may have several openings
formed in it in which steel or other moveable chambers are screwed,
cach one containing its own charge of powder. The emission of
gases under great pressure from each cell as they are successively
discharged into a space occupied by gases of very much less density
produces a powerful reactive force, which I propose to utilize in the
following manner:-Instead of making a massive steel or other
metallic cellular cartridge I bore up the rear end of the projectilo
and form it into several cells, or I form these cells by casting and
strengthen the projectile with hoops. Each cell will receive a charge of
gunpowder or other explosive material, and be secured by a cap or
covering sufficiently strong to prevent the gases accumulated in contact
with it from forcing their way into the cell. These caps may be of
thin steel coated with softer metal and screwed or caulked into the
mouth of each cell, and may be provided with a percussion cap for
the discharge of the cell which they close up. In guns employed to
discharge such projectiles I form two sets of rifled grooves, one of which
series is for the purpose of giving rotation to the projectile, and these
I prefer to make of a differential pitch, using revolving or self-adjusting
studs to move therein. The second set of grooves (or a single groove)
is made in the reverse direction to those before-named, or the groove
or grooves may be made parallel to the axis of the gun, so that an arm
or projecting lever having an axis coincident with and connected to the
centre of the projectile may have a stud or studs formed on it, which
take into the Inst-named groove or grooves, and thus as the projectile
moves along the chase of the gun the arm or lever jointed to it will
have a different or opposite rotation to that of the projectile communi-
cated to it, which brings the arm or lever successively over each of the

page_text: percussion caps, whether the same be attached to the covers of the cells
or at or near the sides of them. A projecting piece from this revolving
arm may thus be made to come in contact with cach percussion cap in
succession, and discharge the cell with which it communicates, or a
small spring hammer attached to the revolving arm may be lifted by a
series of inclines formed on the projectile as the arm revolves and fall
at the right moment on to each percussion cap. In either case it will
be seen that the reactive force or recoil caused by the explosion and
emission of gases from each of the cells under enormous pressure into
the bore of the gun, (where a comparatively low pressure only is kept
up) will tend to force forward the projectile and greatly assist in its
propulsion, while the force of recoil upon the gun will be diminished.
In some cases the reactive force of successive explosions from the pro-
jectile may be made the sole means of propelling shells or other
projectiles of enormous weight from comparatively thin tubes open at
both ends.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Bessemer in the Great Seal Patent Office
on the 1st December 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Denmark Hill, in the County of Surrcy, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of June, in the year of our
Lord One thousand eight hundred and seventy-one, in the thirty-fourth
year of Her reign, did, for Herself, Her heirs and successors, 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 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 ORDNANCE AND PROJECTILES," upon the condition (amongst others) that I,

page_text: the said Henry Bessemer, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and scals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the
samo 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 Henry Bessemer, do hereby declaro
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 :—
My present Invention relates to improvements in the class of guns
and mortars in which the projectile is propelled by a succession of
separate discharges of gunpowder or other explosive material as it moves
along the chase of a gun or mortar of unusual length. For ordnance of
this class Letters Patent were granted to me bearing date the 29th day
of November 1870, and numbered 3130.
Now my present Invention consists in modifications and details of
construction and improvements in carrying into practical operation
this continuous low pressure system of ordnance, and which I will
now proceed to describe.
In building up guns or mortars composed of two or more cylinders
placed end to end I employ flanged hoops, in the interior of which
a number of concentric grooves are formed. A similar series of grooves
are formed on those parts of the cylinders where these flanged hoops
are to be shrunk or forced on. I make suitable holes or channels in
these hoops, through which I pour fluid iron or other metal or alloy
into the annular cavities thus formed. The iron or other metal when
solidified forms a scrios of keys or feathers which effectually prevent
the removal of the hoop from the cylinder. In like manner I secure
the trunnion ring, breech, or other cylinders or hoops employed in
built up guns. A hard alloy of copper, tin, and bismuth is well suited
for use for this purpose; the latter metal lessens or prevents the shinking
of the alloy in cooling.
In order that this system of connecting flanged hoops and other rings,
hoops, or cylinders may be fully understood, I have hereunto annexed
a Sheet of Drawings, on which Figure 1. represents a portion of a tube
or cylinder having a number of rings or channels & formed around

page_text: .
its external surface; Figure 2 represents a flanged hoop c in section,
having on its interior surface a series of channels & at distances apart
corresponding to the channels 6 in Figure 1. The tube a is shewn
at Figure 3. with the flanged hoop c shrunk or forced on to it, the
spaces between the channels running entirely round the cylinder a.
Other hoops to strengthen the cylinder are also shrunk or forced on.
as shewn at e. Several holes are drilled at the end of the flange c,
as shewn at f and 7, Figure 4. These holes are bored as far in as to
reach the channel farthest from the end of the cylinder a, and thus
establish a connection between cach channel and afford access to them.
The small holes f serve for the escape of air, and the larger ones g are
for the purpose of pouring fluid metal into the channels, and thereby
casting a series of metal keys or feathers extending around the cylinder,
and thus preventing the flange from being drawn off by any amount
of forco short of that which would shear the metal in all the channels
simultaneously. I prefer to pour in the fluid metal at several holes
simultaneously while the shrunken flange is still very hot, a small
funnel lined with loam being placed over each of the holes g to facilitate
the casting operation. The air is driven out of the holes f. The bolt
holes in the flanged hoop. are shewn at h by means of which the
cylinder a may be joined to another one of similar construction. In
order to weaken the cylinder and the flange as little as may be I
prefer to vary the depths of the channels as shewn on a larger scale
at Figure 5, which represents a portion of a flange and cylinder, the
same letters of reference being employed as in the other Figures. It
will be observed that the channels 1 to 6 are made progressively
deeper towards the end of the cylinder a, and that the channels d
in the flanged hoop c arc deepened in the opposite order. Thus a
sufficient space is afforded to form a strong key of cast metal without
weakening the cylinder or flange to the same extent as would be
the case if the channels were all of an uniform depth. m shows the
cast keys as they would appear in section, filling the channels and
holding the flanged ring firmly in place. A similar mode is shewn in
Figure 7 applied to the uniting of a number of short cylinders; i repre-
sents the inner series of cylinders, and ; the outer scries shrunk on to
them. The sunk channels are filled with fluid metal as each successive
cylinder is added. In some cases it may be found preferable to
make the holes for filling in the metal in a radial direction to the

page_text: axis of the cylinder, one or more such openings being made into each
channel.
In Figure 8 I have shown the manner in which the breech of a gun
may be permanently secured in place by cast metal keys or rings and
also the mode of securing a trimnion hoop n to a gun by similar means.
I would further observe that cast iron alone may be used for filling up
channels in the manner described, but when these channels aro small
I prefer to employ an alloy of tin and copper in the proportion of ten to
twenty parts of tin to eighty or ninety parts of copper, in some cases
adding from five to ten parts of bismuth in lieu of an equal quantity of
tin. Many other metals or alloys may be used for this purpose, care
being taken that the area of metal to be sheared shall be such as to fully
withstand the maximum force employed.
In the construction of ordnance and projectiles according to my present
improvements I proceed as follows:-Instead of making a massive steel
or other metallic cellular cartridge as is described in the Specification of
my former Patent herein-before referred to, I bore up the rear and of
the projectile and form it into several cells, or I form these cells by
casting and strengthen the projectile with hoops. Each cell will receive
a charge of gunpowder or other explosive material and be closed and
secured by a cap or covering sufficiently strong to prevent the gases
accumulated in contact with it from forcing their way into the cell.
These caps may be of thin steel coated with softer inetal and screwed or
caulked into the mouth of each cell, and may be provided with a
percussion cap for the discharge of the cell which they close up, but I
prefer to place tho percussion cap at a short distance from the cap or
covering of the cell it is intended to discharge.
In guns employed to discharge such projectiles I form two sets of
rifled grooves, one of which series is for the purpose of giving rotation
to the projectile, and these I prefer to make of a differential pitch, using
revolving or self-adjusting studs to move therein. These revolving studs
are shown at S in Figures 11 and 12 fitted to the projectile in such a
manner that the clongated projecting part which fits the rifled groove
may alter its angle of inclination to suit the varying angle of the
increasing pitch of the rifled groove as described in a Patent granted 3
to me and dated the 14th day of August 1867, No. 2343. The second
ect of grooves (or a single groove) is made in the reverse direction to

page_text: those before named, or the groove or grooves may be made parallel to
the axis of the gun, so that an arm or projecting lever having an axis
coincident with and connected to the centre of the projectile may have
a stud or studs formed on it which take into the last named groove or
grooves, and thus as the projectile moves along the chase of the gun the
arm or lever jointed to it will be prevented from rotating, or it may have
a different or opposite rotation to that of the projectile communicated to
it, which brings the arm or lever successively over each of the percussion
caps, whether the same be attached to the covers of the cells or at or
near the sides of them. A projecting piece from this revolving arm
may thus be made to come in contact with each percussion cap in
succession and discharge the cell with which it communicates, or a small
spring hammer attached to the revolving arm may be lifted (by a series
of inclines formed on the projectile) as the arm revolves and falls at the
right moment on to each percussion cap. In either caso it will be seen
that the reactive force or recoil caused by the explosion and emission of
gases from each of the cells under enormous pressure into the bore of
the gun (where a comparatively low pressure only is kept up) will tend
to force forward the projectile and greatly assist in its propulsion, while
the force of recoil upon the gun will be diminished.
In order that the mode in which this part of my Invention may bo
carried into effect and may be most fully understood, I have shown the
same on the Sheet of Drawing hereunto annexed, where Figure 11
represents a longitudinal section of a projectile, and Figure 12 an
elevation of the same. A, A, are a sèrics of cells cast or bored in the
projectile. There are sixty of theso cells in the projectile here repre-
sented, each of which contains a charge of gunpowder or other explosive.
The mouth of cach cell is securely closed by a steel disc enclosed in a
softer metal, such as zinc.
This cap or stopper is shewn in section on a larger scale at Figure 9,
where C represents a curved steel disc having perforations therein so as
to allow the zinc or other metallic part of the stopper D to be united on
both sides of the disc. The mouth of cach cell is enlarged, and a screw
thread, as shewn at B*, is formed in the enlarged part. The stopper D
has also a screw thread formed upon it, and it is screwed home to the
shoulder or seating formed by the bottom of the enlarged part. When
screwed home the outer surface of the soft metal is caulked by a steel

page_text: tool and rendered perfectly gas-tight. The steel disc abutting against
the scating is strong enough to withstand the external pressure of the
gases occupying the chase of the gun, while the pressure from within
when the contents of the cell is exploded will only have to strip the
thread of the soft metal, which also by enclosing the steel disc prevents
injury to the interior of the chase of the gun when the metal cap is
blown out of the mouth of the cell. The ignition of the powder or other
explosive is effected by a percussion cap E fitted on to a nipple G, which
is screwed to the rear of the projectile near to the cell it is intended to
explode, and communicating with it by a passage H.
axis N is fitted, and is provided
The general arrangement of the cells is shown in Figure 10, where K
represents one of the flanges by which the several lengths of the gun aro
connected. L is the inner tube, and M one of a series of hoops by which
the tube is strengthened, the hoops and flanged rings being by pre-
ference secured to the inner tube or cylinder in the manner before ]
described and represented in Figure 3. In the centre of the base of tho
shot a hole is bored into which a steel
with a screw thread N° at its inner end, by means of which it is held in
place, but so nevertheless that it may make one complete revolution
without withdrawing it more than the distance of the pitch of one
thread. The outer end of the arm P is made to fit freely into a channel
or groove formed along the interior of the chase of the gun, as shewn
at Q, Figure 10. Rifled grooves are also formed at R for the purpose of
giving rotation to the projectile.
gun
The cells A are shown on a larger scalo in Figure 13, which represents
an end view of the projectile, one half in section and one half in
clevation. It also shews the position of the percussion caps E and the
arm P. Now if the rifled grooves Rare of an uniform pitch, and the
groove Q is a straight light running parallel to the axis of the gun, it
follows that the motion of the projectile along the chase of the
will 3
produce in it an uniform rotatory motion, while the end of the arm P
travelling along the straight groove Q will be prevented from being
turned round, and will occupy the position shown in Figure 10 during
the whole time that the projectile is travelling along the chase of the
gun; hence by the rotatory motion of the projectile the percussion 3
caps E will be brought successively in contact with the arm P, and in
this way they will explode the charge of powder in the cells with which

page_text: they communicate; and thus it happens that the discharge of the
60 cells will follow each other as the projectile moves through regular
distances with that degree of accuracy which the rifling, acting as a
dividing screw, is capable of giving. In a gun whose length is 60 fect
I should prefer to discharge one of the 60 cells for every 8 inches
traverse of the projectile, thus exploding the whole by the time the
projectile has traversed 40 feet of the chase of the gun, so that after
the combustion of the charges has taken place the expansion of the
accumulated gases completes the discharge of the projectile.
In guns in which these loaded projectiles are employed I prefer to
form one cell in the breech plug of the gun, and this charge (which I
call the starting charge) may be fired by electricity or by a fusee in the
ordinary way, thus commencing the motion of the projectile, which will
of itself keep up the supply of gases until all the cells are discharged.
In constructing ordnance on this principle we first fix the maximum
pressure to which it is intended to subject the gun, and then ascertain
how much powder will produce the required pressure in so many inches
of the chase of the gun as it is intended the projectile shall travel
between the successivo discharges of the cells. From these elements
the weight of the charge for the gun and the length of chase requisite
are found, for the predetermined low pressure is capable, when a
sufficient time is allowed for its action on the projectile, of doing as
many foot pounds of work as is obtained in ordinary guns by an excessive
but rapidly decreasing pressure. It will be possible to propel projectiles
of three to five tons in weight at velocities comparable with those
obtained by the ordnance now in use when employing pressure not ex-
cceding 4000 to 6000 pounds per square inch in steel guns not exceeding
6 or 8 inches in thickness of metal, and exposed to strains considerably
below the clastic limit of the metal of which they are constructed. It
will be observed that in discharging the separate cells as the projectile
moves along the gun that it supplies the required quantity of gas to
keep up the pressure irrespective of the velocity of its motion, and also
that the gases so formed have not to traverse the whole length of the
gun, but are gencrated at the rear of the shot where their action is
required, and further that the force generated in the cells at each suc-
cessive explosion over and above the pressure of the gases occupying
the chase of the gun will by their reactive force or recoil assist in the

page_text: propulsion of the projectile, but will not act with this high pressure on
the chase of the gun by reason of its being, in the case supposed,
120 times more in sectional area than either of the cells which discharge
themselves into it.
It will be understood that when a differential rifling having a t
continually increasing pitch is employed in ordnance used for dis-
charging a number of cells successively that the groove in which the
arm P travels must not be a straight groove, but it must be made of a
differential pitch the reverse of the rifled grooves, so that this compound
differential motion shall result in an uniform motion of the arm against 1
the percussion cap as the shot revolves.
Having thus described the nature of my Invention, and the manner in
which the same may be carried into operation, I desire it to be under-
stood that I do not confine myself to the precise details herein specified,
provided the distinctive characters of my Invention be retained; but 1
what I do claim is,-
Firstly. I claim in the construction of built up guns the employment
of grooves or channels into which fluid metal is run to form keys to
connect the parts, substantially as described.
Secondly. I claim the construction of projectiles with a number of 2
cells containing separate charges of gunpowder or other explosive matter
arranged so that they may be fired in succession to propel the projectile,
substantially as described.
Thirdly. I claim the employment of a moveable arm or lever attached
to a projectile, and guided by a groove formed in the gun for the purpose:
of discharging successive charges of gunpowder or other explosive matter
contained in the projectile, substantially as described.
Fourthly. I claim the general arrangement of cells in the projectile,
and the mode of closing the same by a compound metal stopper, sub-
stantially as described.
Fifthly. I claim the construction of projectiles in such manner that
when they have been started along the chase of the gun by the explosion
of a starting charge contained in or at the breech of the gun, a series
of charges contained within the projectile are in succession exploded,
substantially as described.
มิ

page_text: Lastly. I claim the combination with projectiles containing separate
charges of gunpowder or other explosive matter of mechanical apparatus
which effects the ignition of each such charge as it arrives at a regular
predetermined distance from the breech of the gun, substantially as
which chilects the ignition of cach such charge as it arrives at a regular
predetermined distance from the breech of the gun, substantially as
described.
In witness whereof, I, the said Henry Bessemer, have hereunto set
my hand and seal, this First day of December, in the year of our
Lord One thousand eight hundred and seventy-onc.
In witness whereof, I, the said Henry Bessemer, have hereunto set
my hand and seal, this First day of December, in the year of our
Lord One thousand eight hundred and seventy-onc.