IMPROVEMENTS IN ORDNANCE AND MACHINERY TO BE USED IN THROWING PROJECTILES, PART PROVISIONAL SPECIFICATION OFHICHACHRY IS APPLICABLE FOR OTHER PURPOSES
Year: 1867

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, Cannon
Street, in the City of London, for the Invention of "IMPROVEMENTS IN
ORDNANCE AND MACHINERY TO BE USED IN THROWING PROJECTILES, PART
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at
the Office of the Commissioners of Patents, with his Petition, on the
14th August 1867. .
I, HENRY BESSEMER, of Queen Street Place, Cannon Street, in the City of
London, do hereby declare the nature of the. said Invention for "[MPROVE
MENTS IN ORDNANCE AND MACHINERY TO BE USED IN THROWING PROJECTILES, PART OF
WHICH MACHINERY IS APPLICABLE FOR OTHER PURPOSES," to. be as follows:―
In the larger description of rifled guns intended to be employed against
armour plates the vis inertia of the elongated projectile is not overcome until
an enormous pressure. is generated by the ignition of a large portion of the
powder and its conversion into gas. The pressure thus suddenly brought to
bear on the interior of the gun acts with destructive force on the metal of
which it is composed before the full resisting action of the exterior portions of
the metal are brought into play, and hence notwithstanding the great thick
ness of metal now employed in the construction of guns their ultimate rupture

page_text: may always be looked for after a certain number of rounds have been fired
from them. No mere thickening of the metal seems capable of preventing
very large guns from bursting, because the enormous pressure employed is
destructive of the innerportions of metal, as manifested bynumeroussmallcracks
which are soon formed on the interior surface of the gun, and which gradually
deepen and impair its strength. The small volume of gas acting on the gun
with such unwonted violence rapidly diminishes in pressure as it expands into
the space left behind the retreating shot, so that the ultimate amount of
force exerted on the projectile is very small in proportion to the strain to
which some portions of the gun are subjected. From the foregoing and other
known causes it will be understood that the construction of ordnance of much
larger calibre than those usually employed is surrounded with many practical
difficulties, and leads to the inference that the employment of,
for throwing projectiles has nearly reached its practical limit.
gunpowder
Now therefore the object of my present Invention is the construction and
working of ordnance capable of throwing projectiles of very large diameter at
moderate velocities, and also of throwing projectiles of ordinary weight at very
high velocities by the employment of a much lower degree of elastic pressure
than results from the explosion of gunpowder, but acting through a longer
distance, the elastic matter employed being in much greater volume than
it is possible to obtain from gunpowder in guns of a like calibre.
In carrying my Invention into practical operation I construct a set of force
pumps worked by steam power, their pistons or plungers acting direct, as will
be hereinafter more particularly described, and by means of which I force
atmospheric air into a receiver until the desired degree of pressure is
obtained: The capacity of the receiver I prefer to be from 1 to 3 times
the capacity of the whole bore of the gun. When gunpowder is employed if
the gases when first formed occupy one foot in length of the bore they will
be expanded into ten times that volume by the time the projectile has reached
ten feet along the bore, and will have suffered a corresponding diminution
of pressure, but in the case of compressed air even where the receiver is
only of the same capacity as the bore of the gun the pressure will only
be reduced to one-half by the time the projectile leaves the gun, and this
is equally true if the bore of the gun be made of four or more times the
length of an ordinary gun, hence it will be perceived how very greatly
the original pressure may be reduced by the employment of compressed air
without in like manner reducing the ultimate effect on the shot, for in the
one case the pressure of the gases acting on the projectile is reduced to one-
teuth, and in the other case the pressure is only reduced one-half after having

page_text: exerted its expansive force through four or more times the distance. It must
however be understood that these figures are only used by way of illustrating
the principle of my Invention, which. admits of various modifications and a
variety of proportions to suit the several objects for which ordnance is con-
structed. In order that the.full propelling force of the compressed air may be
obtained it is necessary that the area of the passage from the receiver and its
jort of admission into the gun should be at least equal to the area of the bore
of the guu, and it is also desirable that the full pressure of the air should be
instantly applied; its passage through a valve in the act of opening would
propel the shot some distance along the bore, or perhaps quite out of it, while
the valve was still only opened a small distance, the shot being thus discharged
with.a force quite inadequate to produce any useful effect. It will be readily
understood that the instantaneous opening of a valve some two or three
square feet in area where pressures of 5,000, to 10,000 lbs. per square inch
are employed present formidable engineering. difficulties; and even if slide or
equilibrium valves of such large dimensions be employed their working: if
practical would be attended with great loss of power and inconvenience, but
in the case of small ordnance they may however. be employed. From.the
causes explained I prefer that the discharge of projectiles from the larger
class of ordnance should not be effected by the admission of air under pressure
to the rear of the projectile thronghi a valve of any kind, but in lieu thereof
The shot is to.be
the projectile may be discharged in the following manner:
formed with packing rings of lead or other suitable material, and be forced
tightly into the gun so as to form an air-tight joint, or it may have a loose
sabot or packing ring of leather or other material placed behind it so as to
form an air-tight joint, a space being left between. the projectile and. the
breech into which the ports open through which the compressed air enters
the gun; the projectile is to be retained in place by a steel bar or catch, the
end of which enters an aperture in the rear end of the shot, and is provided
with a sliding wedge (constructed after the manner of an implement known
to masons as a "Lewis "), and by means of which the shot is held firmly, in
place; the gun having been thus charged.the forcing of air into the receiver
may be proceeded with, the communication between the receiver and the rear
of the shot being kept open after the desired pressure has been attained.
The discharge of the shot may at any moment be effected by means of a rod
passing through a stuffing box in the breech piece, which will liberate the
wedge of the "Lewis," and allow the shot to commence its flight, urged by
the full force of the compressed air through the open ports. behind it::.
It will be obvious that a great variety of mechanical contrivances may be

page_text: made for retaining and detaching the projectile, but in all of them the same
principle is involved, viz', that the compressed air has free access to the rear
of the shot, and from the moment the shot is liberated exerts its full force
thereon. This mode of holding the shot against the pressure of the air is
more suitable for small than for large calibres.
I however desire it to be understood that the mode which I prefer of
throwing heavy projectiles by means of compressed air is as follows:-I con-
struct a gun having a moveable breech, near to which is formed a series of
slots or ports (or an annular opening) leading from the receiver into the bore
of the gun, the aggregate area of these openings is somewhat larger than the
bore; at the part where these ports are formed the bore is very slightly con-
tracted, and into this contracted part the projectile is forced by a screw or by
suitable hydraulic or other apparatus attached to the gun. I form a shallow
groove or ring at each end of the cylindrical part of the projectile, which I fill
with lead or other metal which is allowed to project slightly beyond the general
surface, or in lieu thereof the whole of the cylindrical part may be coated with
lead or other suitable substance. When the projectile is forced into its place
the ports leading into the gun will be entirely closed by the tight fitting of the
lead rings, so that the compressed air in the receiver cannot enter the gun
nor otherwise escape; while the projectile occupies this position it will effec-
tually close up the ports which communicate with the bore of the gun, but
the pressure exerted upon it being in equilibrium there will be no tendency to
move the projectile along the bore of the gun. Beyond the rear end of the
projectile I make a very small tubular passage into the gun communicating
between the compressed air chainber and the small unoccupied space left
between the projectile and the breech of the gun; this passage is provided
with a two-way cock or with other suitable valves in such manner that by
turning a small handle or lever any air that may accumulate between the
rear of the shot and the breech may be let out, and by reversing the handle
the compressed air in the receiver will rush in through the small passage
and occupy the space, and by its elastic force push forward the projectile
a few inches and thereby admit air by the several ports, which will dis
charge the projectile with a force and velocity dependent on the elasticity
of the air and the weight of the projectile.
Although I have herein-before mentioned that great difficulty may attend
the employment of large valves when required to be opened suddenly and
under great pressure, I nevertheless desire it to be understood that a cone
valve or slide valves may be employed to prevent the compressed air from
entering the ports of the gun; if a small valve or cock be employed to admit

page_text: air to the back of the large one and restore the equilibrium of pressure before
opening it this arrangement will allow the receiver to be charged before.or
during the time of putting the projectile therein. The receiver before referred
to may consist of one or several strong tubes running parallel to the bore of
the gun and connected with it near the breech, or the receiver may be entirely
detached from the gun carriage and communicate with the gun by a gland
and stuffing box at one of the trunnions; a pipe communicates from thence
to the breech of the gun. A telescopic joint may also be made so as to
admit of the recoil of the gun without disconnecting the air pipes leading to
the receiver or to the air pumps; the pressure exerted in this jointed tube
will check the recoil, and may if desired be made to work the guu back into
position; but in most cases I prefer to make the receiver in the form of a
jacket around the gun or around the breech end of it, between the inside of
which jacket and the exterior of the gun the compressed air is contained, and
is thus in close connection with the bore of the gun, the parts before men-
tioned establishing a direct communication between them. The inner cylinder
forming the bore of the gun may consist of one or more steel tubes united by
flanges, and the jacket I prefer to make of the same material, either drawn,
rolled, or bored from a solid forging, but for the larger description of guns a
number of steel rings or hoops may be rolled (after the manner of rolling
railway wheel tyres) with flanges, and be bolted or rivetted together, or be
united by snugs and straps. Or the gun or jacket may consist of a number of
tubes placed end to end with hoops covering the joints and rivetted after the
manner of "butt joints." In some cases two or more series of cylinders may
be shrank on over each other so as to break joint, and over these and rivetted
or otherwise secured thereto I fit several longitudinal flanged bars of steel
running the whole length of the gun, or so far as the air receiver extends,
and over these ribs I fit other cylinders or hoops so as to form a series of
spaces or air chambers running parallel to the gun, and whereby a great
degree of strength is obtained and stiffness in the gun, without the employment
of a great weight of metal, the longitudinal bars serving also as a means of
supporting the end strain on the breech. The rivet holes may be coned or
otherwise countersunk, and the whole of the parts be put together somewhat
after the mode of boiler or girder making, except that the metal is much
thicker, the hoops-are-entire,-and-the-parts-turned, bored, and fitted so as to
form tight well fitting joints. Small guus with separate air cells may be
formed by founding in-iron, steel,-or-bronze-instead of being built up_as_
herein-before described.
Guns constructed for the purpose of throwing heavy projectiles in the

page_text: manner before described may be either smooth in the bore or rifled, and when
intended to throw spherical shot a "sabot" of a cylindrical form externally
must be made to hold the shot and form the necessary air-tight joint at the
ports. When rifled shot are to be thrown from long guns by compressed air
I prefer to form the grooves therein at an increasing pitch, commencing
nearly parallel with the axis of the shot and terminating with the maximum
twist required; the studs on the projectile are for this purpose let into circular
recesses formed on the shot so that they may turn sufficiently to suit the
varying angle of the grooves. It will be obvious that this mode.
may also be
used in ordnance employing gunpowder to discharge the shot.
In guns employing compressed air the closing of the breech may be effected
by any known suitable arrangement, but I prefer to employ a screw breech
piece movable in a hinged socket so as to be readily moved on one side when
required, or a wide groove may be formed around an enlarged part of the
bore of the gun near to the end of it, into which several openings or notches
are made for the admission of corresponding projections formed around a
circular plate or cover; these projections have their surfaces formed into
inclines corresponding with similar inclines formed between the before-named
openings so that the plate or cover may be inserted, and by turning it partly
round it will wedge itself firmly into its seat, a cup leather or elastic ring of
any suitable material serving to prevent the escape of any air past the plate.
When throwing heavy projectiles I prefer to rise them to the required level
of the gun, and to force them into their seats by a hydraulic cylinder and
plunger actuated by water under pressure of air in a small vessel or chamber
constructed for that purpose, or actuated direct by a hydraulic pump worked
by the steam engine, such movements of the gun as are required may also be
effected by similar means. And I would also remark that when
guns worked
by compressed are made of great length the trunnions and centre of lateral
motion may be made near the muzzle end of the gun instead of near the
centre of the gun as trunnions are usually made. The retardation of the
projectile caused by the power absorbed by the rapid expulsion of the atmo-
sphere which occupies the bore of the gun in front of the shot may be greatly
diminished by employing a light cover fitted air-tight to the muzzle of the
gun, and by means of a small pipe connected near the muzzle and leading to
the inlet port of one of the air compressing cylinders the air may be with-
drawn from the bore of the gun so as to form in front of the shot a vacuum,
or at least a less dense atmosphere, depending on the-perfection with which
the "sabot" or packing rings prevent the passage of air past the shot. I
would here remark that the absence of this inteuse heat and pressure accom™

page_text: panied by the deposit of solid matter common to guns firing powder admits
of the use of materials to form an air-tight joint and a nicety of fit in the
projectile which has not hitherto been possible with ordinary guns. When
projectiles from one to ten tons in weight are required I prefer to make thém
of a slightly elongated form, the ends being part of a true sphere of a diameter
equal to the length of the shot, but it is evident that projectiles of other forms
may be used when desired.
The form of air-pumping apparatus which I prefer to employ, and which
may also be employed for other purposes where air under great pressure is
required, consists of a pair of horizontal high-pressure steam cylinders placed
side by side in a light rivetted frame of wrought iron or steel. The piston
rods are each keyed to a cross head the end of which works between slide
bars. Two connecting rods attached to half cranks fixed on the ends of a
short shaft at right angles give motion to a fly wheel of small diameter placed
'between them.
The air pumps consist of a pair of bronze cylinders with hollow plungers of
the same material working through stuffing boxes and glands,and are attached
direct to the steam piston rods which pass out of the back ends of the steam
cylinders; there are also two smaller bronze pump cylinders with plungers of
the same material which communicate with each of the first-named air
cylinders by a passage and valves, so that each steam cylinder works a pair of
air pumps, one a large and the other a smaller one. "The plungers of the small
cylinders work in opposite directions to the large ones. When this apparatus
is set in motion air of atmospheric density or air more or less compressed from
a suitable receiver is taken in at the inlet valves of the large cylinders, and
on the return stroke is forced into the small pumps, its density having been
considerably increased on the reversing of the stroke of the engine; the small
cylinders further compress the air, delivering it into the receiver in order to
economize time; in charging the receiver a supplementary vessel or vessels
may be employed into which air is forced during any spare interval of time,
and can when required be admitted to the receiver attached to the gun, or it
may be supplied to the force pumps in lieu of air at atmospheric density, and
whereby a higher pressure may be obtained. I would also remark that I
prefer to make one pair of air pumps much larger than the other, so that at
the-commencement of the work both pairs of pumps may be employed; but
when the pressure becomes too great for the power of the engine a valve may
-be-opened-so_as_to_stop_the_action of the small pair of pumps, both steam
cylinders being employed in working the large air pumps only; and so in like
nanner when the pressure has again increased the large pair of air pumps are

page_text: to be thrown out of work and the smaller pair only employed to bring up
the pressure to its maximum. I prefer to place the air pumps in a cistern
supplied with cold water in order to absorb as much as possible the heat
given out by the compression of the air, the pumps will thus be kept cool,
the hollow plungers to which the water in the cistern has access assisting
in reducing the temperature of the apparatus. The air may be still further
cooled before entering the receiver if found necessary by passing it in a
small pipe immersed in water. The size of the engine and air pumps will
depend on the size of the guns they are intended to work and the degree
of pressure employed; but I should prefer them being made of a size
capable of charging a gun in four or five minutes.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Bessemer in the Great Seal Patent Office on
the 14th February 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, Cannon Street, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of August, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Henry Bessemer, Her special licence that I, the said Henry Bessemer,
my executors, administrators, and assigns, or such others as 1, 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 MACHINERY TO BE USED IN THROWING PROJECTILES, PART OF WHICH
MACHINERY IS APPLICABLE FOR OTHER PURPOSES," 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.

page_text: NOW KNOW YE, that I, the said Henry Bessemer, 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 thereof, that is to say:-
In the larger description of rifled guns intended to be employed against
armour plates the vis inertia of the elongated projectile is not overcome until
an enormous pressure is generated by the ignition of a large portion of the
powder and its conversion into gas. The pressure thus suddenly brought to
bear on the interior of the gun acts with destructive force on the metal of
which it is composed before the full resisting action of the exterior portions
of the metal are brought into play, and hence, notwithstanding the great
thickness of metal now employed in the construction of guns, their ultimate
rupture may always be looked for after a certain number of rounds have been
fired from them; no mere thickening of the metal seems capable of preventing
very large guns from bursting, because the enormous pressure employed is
destructive of the inner portions of metal, as manifested by numerous small
cracks which are soon formed on the interior surface of the gun, and which
gradually deepen and impair its strength. The small volume of gas acting on
the gun with such unwonted violence rapidlydiminishesin pressureasitexpands
into the space left behind the retreating shot, so that the ultimate amount of
force exerted on the projectile is very small in proportion to the strain to
which some portions of the gun are subjected. From the foregoing and other
known causes it will be understood that the construction of ordnance of much
larger calibre than those usually employed is surrounded with many practical
difficulties, and leads to the inference that the employment of gunpowder
for throwing projectiles has nearly reached its practical limit.
Now therefore the object of my present Invention is the construction and
working of ordnance capable of throwing projectiles of very large diameter
at moderate velocities, and also of throwing projectiles of ordinary weight
at very high velocities, by the employment of a much lower degree of elastic
pressure than results from the explosion of gunpowder, but acting through
a longer distance the elastic matter employed being in much greater volume
than it is possible to obtain from gunpowder (employed in the ordinary
manner) in guns of a like calibre.
In carrying my Invention into practical operation I construct a set of force
pumps worked by steam power, their pistons or plungers acting direct, as will
be herein-after more particularly described, and by means of which I force
atmospheric air into a receiver until the desired degreeof pressure is obtained;
the capacity of the receiver I prefer to be from 1 to 3 times the capacity of the

page_text: whole bore of the gun. And here I would remark that although I prefer to
employ atmospheric air under pressure for the purposes of my Invention in
lieu of the gaseous matter obtained by exploding gunpowder, that I am aware
that similar results may be obtained in my improved ordnance by generating
or forming any permanent gas under pressure from such chemical substances
as are known to be capable of generating gas of considerable pressure in close
vessels, and also by the ignition of meal powder or of any composition
analogous to it, or to " rocket composition," or by igniting anylike matters that
contain nitre or other substances capable of sustaining combustion in close
vessels, and of generating therein gases of sufficient elasticity by a continuous
"and quiet action without exploding, and by this means accumulate in any
close vessel gases which may remain under pressure in readiness to be
liberated at any desired time, and thus propel a projectile in the manner
herein described as applicable to the throwing of projectiles by the liberation
of atmospheric air from confinement in close vessels, and so in like manner it
will be obvious that steam may be employed, although its liability to conden-
sation and the high temperature necessary to obtain the desired pressure
render its employment much less suitable than compressed air, which doesnot
condense by cooling like steam. By the employment of atmospheric air there
can be no escape of noxious vapours from the breech of the gun, there will
be no smoke to prevent the gunners from seeing the position of the enemy,
and the danger attendant on the stowage of gunpowder is entirely avoided,
and at the same time a much cheaper motive power will be obtained from
coal than can result from the use of gunpowder however employed. I would
also remark that when gunpowder is employed in the ordinary way that if the
gases when first formed occupy one foot in length of the bore of the gun they
will be expanded into ten times that volume by the time the projectile has
reached ten feet along the bore, and will have suffered a corresponding dimi-
nution of pressure, but in the case of compressed air, even where the receiver
is only of the same capacity as the bore of the gun, the pressure will only be
reduced to one-half by the time the projectile leaves the gun; and this is
equally true if the bore of the gun be made from one to four or more times
the length of an ordinary gun, hence it will be perceived how very greatly the
original pressure may be reduced by the employment of compressed air
without in like manner reducing the ultimate effect on the shot, for in the
one case the pressure of the gases acting on the projectile is reduced to one-
tenth, and in the other case the pressure is only reduced one-half,after having
exerted its expansive force through four or more times the distance. It
must however be understood that these figures are only used by way of illus-

page_text: trating the principle of my Invention, and are not stated as the actual measure
of the force employed, which will be greatly modified by the reduction of
temperature and the consequent reduction of pressure caused by the expansion
of the gases into the constantly increasing space left behind the projectile as it
moves along the bore of the gun. It will also be understood that my Invention
admits of various modifications and a variety of proportions to suit the several
objects for which ordnance is constructed. In order that the full propelling
force of the compressed air may be obtained it is necessary that the area of
the passage from the receiver and its port of admission into the gun should be
at least equal to the area of the bore of the gun; and it is also desirable that
the full pressure of the air should be instantly applied; its passage through a
valvein the act of opening would propel the shot some distance along the bore, or
perhaps quite out of it, while the valve was still only opened a small distance, the
shot being thus discharged with a force quite inadequate to produceany useful
effect. It will be readily understood that the instantaneous opening of a valve
some two or three square feet in area where pressures of 5,000 to 10,000 lbs.
per square inch are employed present formidable engineering difficulties,
and even if slide or equilibrium valves of such large dimensions be employed
their working, if practicable, would be attended with great loss of power and
inconvenience, but in the case of small ordnance they may however be
employed.
From the causes explained I prefer that the discharge of projectiles should
not be effected by the admission of air under pressure to the rear of the
projectile through a valve of any kind opening slowly, but in lieu thereof the
projectile may be discharged in the following mauner:-The shot is to be
formed with packing rings of lead or other suitable material, and be forced
tightly into the gun, so as to form an air-tight joint; or it may have a loose
sabot or packing ring of leather or other material placed behind it so as to
form an air-tight joint, a space being left between the projectile and the
breech into which the ports open through which the compressed air euters
the gun; the projectile is to be retained in place by a steel bar or catch, the
end of which enters an aperture in the rear end of the shot, and is provided
with a sliding wedge (constructed after the manner of an implement known to
masons as a "Lewis"), and by means of which the shot is held firmly in
place; the gun having been thus charged the forcing of air into the receiver
may be proceeded with, the communication between the receiver and the rear
of the shot being kept open. After the desired pressure has been attained
the discharge of the shot may at any moment be effected by means of a rod
passing through a stuffing box in the breech piece, which will liberate the

page_text: wedge of the "Lewis," and allow the shot to commence its flight urged by
the full force of the compressed air through the open ports behind it.
It will be obvious that a great variety of mechanical contrivances may be
made for retaining and detaching the projectile, but in all of them the same
principle is involved, viz., that the compressed air has free access to the rear
of the shot, and from the moment the shot is liberated exerts its full force
thereon; this mode of holding the shot against the pressure of the air is more
suitable for small than for large calibres.
I however desire it to be understood that the mode which I prefer of
throwing heavy projectiles by means of compressed air is as follows:-I
construct a gun having a moveable breech, near to which is formed a series of
slots or ports (or au annular opening) leading from the receiver into the bore of
the gun; the aggregate area of these openings is somewhat larger than the
bore. At the part where these ports are formed the bore is very slightly
contracted, and into this contracted part the projectile is forced by a screw or
by suitable hydraulic or other apparatus attached to the gun. I form a
shallow groove or ring at each end of the cylindrical part of the projectile,
which I fill with lead or other metal, which is allowed to project slightly
beyond the general surface, or in lieu thereof the whole of the cylindrical part
may be coated with lead or other suitable substance. When the projectile is
forced into its place the ports leading into the gun will be entirely closed by
the tight fitting of the lead rings, so that the compressed air in the receiver
cannot enter the gun nor otherwise escape while the projectile occupies this
position; it will effectually close up the ports which communicate with the
bore of the gun, but the pressure exerted upon it being in equilibrium there
will be no tendency to move the projectile along the bore of the
Beyond the rear end of the projectile I make a very small tubular passage
into the gun communicating between the compressed air chamber and the
small unoccupied space left between the projectile and the breech of the gun;
this passage is provided with a two-way cock or with other suitable valves in
such manner that by turning a small handle or lever any air that may
accumulate between the rear of the shot and the breech may be let out, and
by reversing the handle the compressed air in the receiver will rush in through
the small passage and occupy the space, and by its elastic force push forward
the projectile a few inches, and thereby admit air by the several ports, which
will discharge the projectile with a force and velocity dependent on the
elasticity of the air and the weight of the projectile.
gun.
Although I have herein-before mentioned that great difficulty may attend
the employment of large valves when required to be opened suddenly and

page_text: under great pressure, I nevertheless desire it to be understood that a cone
valve or slide valves may be employed to prevent the compressed air from
entering the ports of the gun. If a small valve or cock be employed to
admit air to the back of the large one and restore the equilibrium of pressure
before opening it this arrangement will allow the receiver to be charged
before or during the time of putting the projectile into the gun. The
receiver before referred to may consist of one or several strong tubes running
parallel to the bore of the gun and connected with it near the brecch. Or the
receiver may be entirely detached from the gun carriage and communicate
with the gun by a gland and stuffing box at one of the trunnions; a pipe
communicates from thence to the breech of the gun. A telescopic joint inay
also be made so as to admit of the recoil of the gun without disconnecting the
air pipes leading to the receiver or to the air pumps; the pressure exerted
in this jointed tube will check the recoil, and may if desired be made to
work the gun back into position. But in most cases I prefer to make the
receiver in the form of a jacket around the gun or around the breech end of
it, between the inside of which jacket and the exterior of the gun the com-
pressed air is contained, and is thus in close connection with the bore of the
gun, the ports beforementioned establishing a direct communication between
them. The inner cylinder forming the bore of the gun may consist of one or
more steel tubes united by flanges, and the jacket I prefer to make of the
same material either drawn, rolled, or bored from a solid forging.
In order that this mode of constructing ordnance may be better under.
stood I have represented a gun so made on Sheet A of the Drawings
hereunto annexed, where Figure 1 is an end elevation, Figure 2 a long-
itudinal section in plau, Figure 3' is a cross section on the line A, B, of
Figure 2, and Figure 4 a cross section on the line C, D, of Figure 2;.
Figure 5 a side elevation of the gun and part of the carriage, the apparatus
for putting in the shot being shown in section; and Figure 6 is a portion
of the breech end of the gun shown in section on a larger scale.
a is a steel tube enlarged at a', and having the trunnions a formed ou
such enlarged part; 6 is the jacket, which is fitted on the outside of the tube a,
and a portion of this jacket is bored to a less diameter at 61, so as to get up
against a shoulder formed on the tube a, at 62 the other end of the, jacket
is thickened out so as to admit of several strong steel studs c being screwed
into it; these studs pass through the boss or enlarged part al of the tube a,
and by means of nuts & the tube and jacket are firmly held together. In
order to increase the length of the bore an additional piece of tube a4 is
fitted with a flange up to the boss a¹, and secured in place by the studs c

page_text: and nuts d; the jacket may be forced on to its seat by pressure, or may be
shrunk on hot, but in order to render it still more air-tight I prefer to fill the
air chamber e with a solution of copper, and to deposit by the use of a battery
a thick coating of that metal all over the interior of the chamber, and thus
effectually prevent any leakage of the air therefrom; fis the projectile, which
may be of any of the forms of elongated projectile now generally employed,
but I prefer it to be what I term the spherical flat zone shot, that is, a simple
sphere reduced in diameter by removing a portion so as to form a flat zone
around it, having a central part which is cylindrical, while the ends retain the
contour of the original sphere; this form is better seen on Sheet B of the
Drawing annexed, where it is shown at Figure 22 within a circular line,
showing how little its form differs from that of a true sphere, although its
weight will be nearly one-third more than a sphere equal to its smaller diameter..
On Sheet B, Figure 23, this shot is shown in section.. ff, are dovetailed
grooves formed around it, into which the lead or other metal bands g, g, are
cut or soldered; Figure 24 represents the shot in elevation, and Figure 25
the shot when forced tightly into a metal hoop or cylinder i, whereby it is
defended from any injury of the lead rings from accidental causes, the metal
hoop being of the proper size to enter freely into the screwed part of the
breech of the gun, so that it may be placed there with its contained shot which
may be forced from it into the contracted part of the breech without any injury
to the soft metal packing rings, after which the hoop will be removed, and
may again be employed for a like purpose. I prefer that the air chamber or
receiver e should be not less in capacity than the entire of the bore of the gun,
and in some cases much larger; at h there are eight ports or openings leading
from the chamber e into the interior of the tube a which forms the bore
of the gun; that part of the tube a where these openings are made is
thickened cut so as to prevent the tube from being unduly weakened at
that part. a, Figure 3, shows the quantity of metal left between the ports.
The projecting ring 61 of the jacket also serves to add strength to that part of
the tube a. The breech may be closed in several different ways, as practised
with other breech-loading guns, but I prefer to employ a screw breech piece
moveable in a hinged socket, so as to be readily moved on one side when
required,or a wide groove may be formed around an enlarged part of the bore
of the gun near to the end of it, into which several openings or notches are
made for the admission of corresponding projections formed around a circular
plate or cover; those projections have their surfaces formed into inclines
corresponding with similar inclines formed between the before-named open-
ings, so that the plate or cover may be inserted, and by turning it partly round it

page_text: will wedge itself firmly into its seat, a cup leather or elastic ring of any
suitable material serving to prevent the escape of any air past the plate. The
first of these arrangements is represented in the Drawing, there is formed on
the jacket a long hinged projection h, to which is fitted an arm having a
boss at its extremity; this boss is bored out truly, and is central with the
bore of the gun; an axis m is fitted into this boss, carrying in one end the
breech screwv n, and at its opposite end the handle p and weight q, the axis m
slides freely through the boss *, so that the breech screw n may be screwed
into the gun and withdrawn therefrom without the arm moving back.
The end of the breech screw is formed into a cone valve at 'n*, which fits
against a conical seating formed on the interior of the tube a, and thus
prevents the escape of air when the gun is discharged.
When throwing heavy projectiles I prefer to raise them to the required
level of the gun, and to force them into their seats by a hydraulic cylinder
and plunger actuated by water under pressure of air in a small vessel or
chamber constructed for that purpose, or actuated direct by a hydraulic
pump worked by the steam engine; such movements of the gun as are
required may also be effected by similar means.
In Figure 5 I have shown a mode of loading the gun by a small hydraulic
cylinder s, which I prefer to make of bronze; it is bolted to an iron plate or
frame secured to the end of the carriage. The gun may be raised or lowered
by a screw or wedges in the usual way, and when it is to be loaded the shot
is rolled on to the frame t, as shown; a ram u is fitted to the cylinder s,and
rendered water-tight in the usual way by leathers. The bottom of the ram is
slightly enlarged, and also fits the interior of the cylinder, leaving an annular
space around the ram in order to adjust the exact distance to which the shot
is forced into the gun. A screw w is fitted into the head of the ram and comes
in contact with the shot f, so that the distance which this screw projects
regulates the distance that the shot will be forced into the gun by the
complete stroke of theram. Water under pressure is admitted by a small four-
way cock (not shown in the Drawing) to the lower end of the ram u by an
opening at X, and by its pressure moves the ram forward and pushes the shot
into the gun with such force as to cause the lead packing rings to be firmly
pressed into the contracted part of the bore in which the ports are situated;
during the forcing in of the shot the water which occupies the annular space V
will escape by the opening Z and be discharged through the four-way cock
before named; on reversing which water, under pressure will enter by the
passage Z and force back the ram into its former position, the water beneath
it escaping by the passage X. When such guns are made of very large size

page_text: it will be found desirable to perform their necessary movements, and also the
lifting up of the projectiles, by hydraulic apparatus adapted specially to each
case, and which will be readily understood by hydraulic engineers. The
necessary pressure on the water may be effected either by suitable force pumps
or by allowing air under pressure to act on the surface of water contained in
a close vessel attached to the gun carriage. The compressed air from the
force pumps may be conveyed to the gun by a pipe of small diameter. In
those cases where the receiver is attached to or forms part of the gun, as in
the modification shown on Sheet A, I prefer the air supply pipe to enter the
trunnion, as shown at a³, where there is a stuffing box and gland provided, so
as to admit of the motion of the gun on its axis without disconnecting it from
the air pipe. A sliding or telescopic joint may be made in the air pipe and
secured in a horizontal position near the lower part of the gun carriage, or it
may be jointed after the manner of a gas bracket, so as to admit of any
motion of the gun carriage without disconnecting the pipe from air pumps.
When the gun has been loaded with a shot in the manner described and the
breech screwed home air may be forced through the air supply pipes into the
jacket until the desired amount of pressure is obtained, the gun will then be
in readiness to be discharged at any moment of time it may be desired to do
so. For this purpose a small cone valve A is fitted into the gun; it has a
cylindrical part formed on it at A¹, which fits accurately into the space it
occupies, and at the back of it is a thin cup B of soft ductile metal such as
copper or fine silver, fitted to the cylindrical part in which it is placed in a
similar manner to the ordinary cup leather used in hydraulic presses. The
spindle of the valve passes through a stuffing box to the exterior of the gun,
where it may be held by a clip or catch so as to keep the cone end of the
valve firmly pressed against its seat. The conical end of the valve closes an
opening C which leads into one of the ports which is in direct communi-
cation with the receiver e; beneath the valve A is a passage D which leads
into the space which is left between the shot and the breech screw. The
valve A has a small hole drilled along its axis with a laterial opening at E
leading into it, so that the air in the receiver by passing along this
passage
gets access to the back of the valve A, and pressing on the annular shoulder
around the spindle nearly balances the pressure on the cone end of the valve,
and thus allows of its movement without much force whenever the clip or
catch which retains it in position is liberated, and which may be effected in
various ways; the one point essential to observe is that a sudden jerk may
detach the clip and allow the small excess of pressure on the cone end of the
. valve to cause it suddenly to open, and thereby admit air under very great

page_text: pressure through the passages C and E into the space behind the shot, the
immediate effect of which will be to force the shot forward. As soon as the
shot moves a very short distance the ports h will commence to admit the
compressed air into the space behind the shot, and by the time the shot has
travelled a distance equal to the length of the ports the entire force of the com-
pressed air will be exerted and the shot propelled with great force and velocity.
In the construction of the larger description of guns a number of steel
rings or hoops may be rolled (after the manner of rolling railway wheel
tyres) with flauges, and be bolted or rivetted together or be united by snugs
and straps; this mode of constructing tubes for guns to be worked by com-
pressed air is shown on Sheet B of the Drawings hereunto annexed, Figure 7
being a longitudinal section of a portion of a tube or jacket so constructed,
and Figure 8 a transverse section of the same. A, A, are the rolled hoops
or rings turned and fitted together, a projecting part of one ring falling
into a corresponding hollow of the next one throughout the series, the whole
being secured firmly together by numerous rivets passing through the
flanges, or the gun or jacket may consist of a number of tubes placed end to
end, with hoops covering the joints, and rivetted after the manner of butt
joints, as represented in longitudinal section at Figure 9, where B shows the
series of tubes, and C the hoops with which they are connected by rows of
countersunk rivets, the tubes and also the hoops having been turned and
fitted before they are rivetted together. Instead of making the hoops
narrower than the tubes I sometimes make them of the same size, as shown in
Figure 10, which is a longitudinal section of a portion of tube so constructed.
In some cases two or more series of cylinders may be shrunk on over each
other so as to break joint in the manner lastly herein described; and over
these, and rivetted or otherwise secured thereto, I fix several longitudinal
flanged bars of steel running the whole length of the gun, or so far as the air
receiver extends, and over these ribs I fit other cylinders or hoops so as to
form a series of spaces or air chambers running parallel to the gun, and
whereby a great degree of strength is obtained and stiffness in the gun without
the employment of a great weight of metal, the longitudinal bars serving also
as a means of supporting the end strain on the breech. The rivet holes may
be coned or otherwise countersunk, and the whole of the parts be put together
somewhat after the mode of boiler or girder making, except that the metal is
nuch thicker; the hoops are entire; and the parts turned, bored,and fitted so
s to form tightwell fitting joints. This mode of forming'a gunwith longitudinal
cells is shown on Sheet B, where Figure 11 is a cross section, and Figure 12 a
ongitudinal section of a portion of a gun so constructed; the longitudinal

page_text: flanged bars G are rivetted to a series of tubes H and I similar to those
shown in Figure 10, and also to an outer tube J, the rivets are counter-
sunk, and the outer part J may be turned, and the series of rings K, K;
forced or shrunk thereon, and when the whole are put together the inner
tube I may be bored out, truly. Small guns with separate air cells may be
formed by founding in iron, steel, or bronze instead of being built up as
herein-before described. A section of a cast gun with cells for containing
compressed air is shown at Figure 13 in cross section; an additional strength
may be given to such cast guns by hooping them, as shown in Figure 14,
where L represents the series of hoops which are forced or shrunk on, and
M a lining of steel to give a greater degree of strength and to resist the
wear which would affect a soft cast metal if much used.
In some cases the flanged bars before described may be made to form the
cellular structure without being rivetted to an inner cylinder, as shown in
cross section at Figure 15, where N, N, are a series of flanged bars rolled to
the segmental form shown; each side of these bars are planed truly to shape,
and a double row of rivets unites them firinly, together, after which the tops
of the flanges may be turned off in a lathe, so that the flanged hoops P may
fit firmly over them. These hoops may be made and fitted together in the same
manner as represented in section at Figure 7, but I prefer that other short
segmental pieces should be fitted in between the flanged bars, as shown at Q
in Figure 16, so that each cell of the series is made complete in itself before
the outer hoops R are forced thereon. Figure 17 shows a portion of a tube
in section on a larger scale.
Guns constructed for the purpose of throwing heavy projectiles in the manner
before described may be either smooth in the bore or rifled, and when
intended to throw spherical shot a "sabot' of a cylindrical form externally
must be made to hold the shot and form the necessary air-tight joint
at the ports. When rifled shot are to be thrown from long guns by com-
pressed air I prefer to form the grooves therein at an increasing pitch
commencing nearly parallel with the axis of the shot and terminating with the
maximum twist required, the studs on the projectile are for this purpose let
into circular recesses formed on the shot, so that they may turn sufficiently to
suit the varying angle of the grooves. It will be obvious that this mode
also be used in ordnance employing gunpowder to discharge the shot.
The mode of fitting the studs to the projectile is shown in Figures 18, 19,
20, and 21, on Sheet B. Figure 18 shows the shot in elevation with the studs
S parallel to the axis; these studs are formed on a conical disc S*, as shown
on a larger scale in Figures 20 and 21. The circular recess is made in the
may

page_text: -projectile, which is dovetailed or undercut, and when the conical part S* of
the stud is placed therein the space V around it is filled with fluid lead;
by this means the stud will be retained in place, but it will be capable of
turning round so as to accommodate itself to the constantly varying angle
presented by the increasing pitch of the rifling.
I would also remark that when guns worked by compressed air are
made of great length the trunuions and centre of lateral motion may be
made near the muzzle end of the gun instead of near the centre of the
gun, as trunnions are usually made; and although I have herein-before
referred to the movement of the gun on its trunnions and otherwise I
nevertheless desire it to be understood that in some cases these large guns
may be permanently fixed in a gun boat or other vessel so that the gun
will derive no other motion than that which is imparted to it by the vessel
itself, or except in so far as it may have a certain liberty of recoil by acting
against suitable buffers; the force of recoil may, however, be much diminished
by allowing the air under pressure to escape laterally or in a direction back ward
from openings made at a short distance from the muzzle of the gun. By fixing
the the
gun.
boat. will serve the purpose of a gun carriage by absorbing
gun
the greater part of the force of recoil, while it will yield slightly to it. The
retardation of the projectile caused by the power absorbed by the rapid
expulsion of the atmosphere which occupies the bore of the gun in front of the
shot may be greatly diminished by employing a light cover fitted air-tight-to
the muzzle of the gun, and by means of a small pipe connected near the muzzle
and leading to the inlet port of one of the air compressing cylinders, the
air may be, withdrawn from.the bore of the gun so as to form in front of the
shot a vacuum or at least a less dense atmosphere depending on the perfection
with which the sabot or packing rings prevent the passage of air past
the shot.
I would here remark that the absence of this intense heat. and pressure
accompanied by the deposit of solid matter common. to guns firing powder
admits, of the use of materials to form an air-tight joint, and a nicety of fit
in the projectile which has.ust hitherto been possible with ordinary guns.
At Figure 26, on Sheet B, 1. have shown the muzzle of a gun with a thin
curved plate of steel T fitted into a recess formed at the end of it.. A ring of
greased leather is fastened to a flat flange formed on the steel plate T for
the purpose of
rendering it air-tight. At U is a small pipe leading to the air
pumps so that when the plate T is placed over the muzzle of the gun, and a,
cock.is opened in the pipe U, the air pump will speedily exhaust the bore of
gun. Before discharging the shot the communication with theairpump is to be,
closed, and when the projectile is set in motion the air which escapes.pas. it.

page_text: will accumulate in front, aud will exceed the pressure of the external
atmosphere, and cause the plate T to drop off or be blown away before the
arrival of the shot at the muzzle of the gun. When projectiles from one to ten
tons in weight are required I prefer to make them of a slightly elongated
form, the ends being part of a true sphere of a diameter equal to the length of a
shot, but it is evident that projectiles of other forms may be used when desired.
The forin of air pumping apparatus which I prefer to employ, and which
may also be employed for other purposes may also be employed for
other purposes, where air under great pressure is required, consists of a
pair of horizontal high-pressure steam cylinders placed side by side in
a light rivetted frame of wrought iron or steel. The piston rods are
each keyed to a cross head, the end of which works between slide bars,
Two connecting rods attached to half cranks fixed on the ends of a short
shaft at right angles give motion to a fly wheel of small diameter placed
between them. The air pumps consist of a pair of bronze cylinders with
hollow plungers of the same material working through stuffing boxes, and
are attached direct to the steam piston rods which pass out of the back ends
of the steam cylinders; there are also two smaller bronze pump cylinders
with plungers of the same material which communicate with each of the
first-named air cylinders by a passage and valve so that each steam cylinder
works a pair of air pumps, one a large and the other a smaller one. The small
plungers of the air cylinders work in opposite directions to the large ones.
When this apparatus is set in motion air of atmospheric density, or air more
or less compressed from a suitable receiver, is taken in at the inlet valves of
the large cylinders, and on the return stroke is forced into the small pumps,
its density having been considerably increased. On the reversing of the stroke
of the engine the small cylinder further compresses the air, delivering it into
the receiver or delivering it into another set of pumps, so as further to
compress the air before it is forced into the receiver. In order to economize
time in charging the receiver a supplementary vessel or vessels may be
employed, into which air is forced during any spare interval of time, and can
when required be admitted to the receiver attached to the gun, or it may be
supplied to the force pumps in lieu of air of atmospheric density, and whereby
a higher pressure may be obtained by a given amount of pumping. I would
also remark that I prefer to make one pair of air pumps much larger than
the other so that at the commencement of the work both pairs of pumps
may be employed, but when the pressure becomes too great for the power
of the engine a valve may be opened so as to stop the action of the small pair.
of pumps, both steam cylinders being employed in working the large air pumps

page_text: only, and so in like manner when the pressure has again increased the large
pair of air pumps are to be thrown out of work, and the smaller pair only
employed to bring up the pressure to its maximum. I prefer to place the air
pumps in a cistern supplied with cold water in order to absorb as much as
possible the heat given out by the compression of the air; the pumps will thus
be kept cool, the hollow plungers to which the water in the cistern has access
assisting in reducing the temperature of the apparatus. The air may be still
further cooled before entering the receiver if found necessary by passing it
in a small pipe immersed in cold water. The size of the engine and air
pumps will depend on the size of the guns they are intended to work, and
the degree of pressure, employed, but I should prefer them being made of
a size capable of charging a gun in four or five minutes.
I however desire it to be understood that I do not confine myself to this
particular form of apparatus or mode of pumping air for the purposes of my
Invention, although the same may be advantageously employed for the
forcing of air for throwing projectiles, and also for other purposes where air
under great pressure may be required, but it will be obvious that the forcing
of air may be accomplished in a variety of ways, as is well understood by
engineers, nor do I confiue myself to the exact mode of constructing an
working ordnance herein-before represented and described; but,-
First. I claim in the construction of ordnance the formation of cells
around the bore of the gun adapted to contain the elastic aeriform matter
to operate by its expansion on the shot.
Second. I claim in the construction of ordnance the employment of longi.
tudinal flanged bars surrounded by cylinders or hoops.
Third. I claim casting ordnance with air cells around the bore as described.
Fourth. I claim the construction of ordnance by building up flauged hoops
or rings by turning such rings or hoops and rivetting the same together.
Fifth. I claim in the construction of ordnance the employment of a tube
and jacket having a space between them for the storing of compressed air
as herein described.
Sixth. I claim forcing the projectile into the gun by means of hydraulic
apparatus, as described.
Seventh. I claim in the construction and working of ordnance causing
the projectile to form the valve closing the main air passages by which air
is admitted to the rear of it for its propulsion.
Eighth. I claim the employment of studs in rifled projectiles arranged
to alter their position to suit the differential pitch of the rifling, as herein
described

page_text: Ninth. I claim the employment of a disc or cover to the muzzle of guns
using compressed air for the propulsion of the projectile and forming a
partial vacuum in such guns, as herein described.
Tenth. I claim constructing ordnance in such manner that the projectile
may be forced into a contracted part of the bore and so retained until when
the discharge is required it is started by the admission of air to its rear by
a small valve or cock.
Lastly, I claim in ordnance constructed to throw projectiles by compressed
air the employment of a cock or valve to prevent the premature accumulation
of air at the rear of the projectile, as herein described.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Fourteenth day of February, in the year of our
Lord One thousand eight hundred and sixty-eight.
HENRY BESSEMER. (L.S:)