IMPROVEMENTS IN ORDNANCE AND IN PROJECTILES USED THEREWITH, AS ALSO IN THE PROCESSES EMPLOYED IN THEIR MANUFACTURE
Year: 1867

page_text: LETTERS PATENT to William Palliser, Major Unattached, of the Army
and Navy Club, Pall Mall, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN ORDNANCE AND IN PROJECTILES USED THEREWITH, AS
ALSO IN THE PROCESSES EMPLOYED IN THEIR MANUFACTURE."
Sealed the 26th May 1868, and dated the 10th December 1867.
PROVISIONAL SPECIFICATION left by the said William Palliser at the
Office of the Commissioners of Patents, with his Petition, on the 10th
December 1867.
I, WILLIAM PALLISER, Major Unattached, of the Army and Navy Club,
Pall Mall, in the County of Middlesex, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN ORDNANCE AND IN PROJECTILES USED
THEREWITH, AS ALSO IN THE PROCESSES EMPLOYED IN THEIR MANUFACTURE," to be
as follows:
My Invention relates,―
Firstly. To improved modes of strengthening or "converting " existing
cast-iron guns.
Secondly. To an improved mode of constructing compound guns com-
posed of a combination of steel, wrought iron, and cast iron, as also to
improvements in the process employed in their manufacture.
Thirdly. To an improved system of rifling guns.
And, lastly. To improvements in the form and manufacture of projectiles
therefor.

page_text: One of my improvements relating to the conversion of existing cast-iron
guns in which a wrought iron or steel lining or barrel is introduced through
the muzzle, as described in the 'Specification to certain Letters Patent granted
to me, and bearing date the 11th November 1862, No. 3038, consists in
forming the breech portion of the lining or barrel with two tubes, of which
the inner or "A" tube is comparatively thin, and is constructed either of steel
of such a quality as will stretch or of coiled wrought iron, which tube I fit
into a seat formed in the outer or "B" tube, which extends the entire length
of the barrel and which may also be either of steel or of coiled wrought iron.
Or, in another arrangement, I make the "A" tube of the entire length of
the barrel, and I reduce the thickness of the breech end thereof externally,
and I fit the "B" tube over such reduced end of the "A" tube. In large
guns where it is not practicable to make the muzzle end of the "A" tube of
such a thickness as to be equal in diameter to the combined thicknesses of
the A and B tube at the breech I increase it up to the required size by
fitting upon it pipes or tubes of cast or wrought iron. The object of making
the A tube thin at the breech. end is, that should the barrel split by the action
of long continued firing, which it is liable to do, such split would not extend
beyond the A tube, and would in consequence only be shallow, and thus the
mechanical advantage gained by the internal pressure of the gas by means of
such shallow split would not be sufficient to burst the thick B tube supported
by the cast-iron casing. It is essential when the barrel is composed of two
tubes throughout, as last described, that the screw collar or "screw washer
at the muzzle, described in the Specification to my before-mentioned Letters
Patent, should secure the inner tube as well as the outer one.
"
Another improvement consists in cutting a helical channel of a quick pitch
either round the external surface of the A tube or in the internal surface of
the B tube, which channel communicates with an indicator hole that passes
out through the breech end of the gun. The object of this arrangement is,
that should the A tube split the gas escaping through such split will at once
find its way through the helical channel to the indicator hole, and thus give
warning to the detachment serving the gun.
Another improvement consists in forming the cup closing the end of the
barrel of a ring of steel or wrought iron, which is converted into a cup by
means of a plug of steel or wrought iron screwed into its centre from the
inside with a countersunk head. The object of this improvement is to obviate
the defect inherent in solid forged cups or solid-ended barrels, in which the
centre portion of the metal is apt to be porous, which enables the powder to
eat a hole into it after a certain number of rounds.

page_text: Another improvement bas reference to the vents of guns generally, and
consists in running the screw thread down the entire length of the bush into
the bore of the gun instead of coning the lower end as heretofore, and
combining with such bush an interior tubular lining of platinum or alloy of
platinum screwed into the lower end of the said bush, which lining may or
may not have a countersunk head upon it.
In constructing new compound guns I either first cast a new cast-iron
casing into which I place a wrought iron or steel barrel, in the manner
berein-before described, or I introduce the barrel into the mould and cast the
casing round the same, in which case I proceed in the following manner :-
The mould for the gun is arranged in a vertical position with the muzzle end
upwards. The wrought-iron or steel barrel is composed of two tubes of either
coiled wrought iron or steel, of which the outer or B tube need only extend
to a certain distance towards the muzzle. This barrel is fixed in the mould
by being secured thereto at the upper end by clamps or other suitable known
means, while the lower end rests on the upper open end of a pipe encased
in loam. The lower end of this pipe passes through the mould and commu-
nicates with a tuyere or blast pipe, through which a current of air is forced by
a fan or other means up through the barrel in the centre of the mould, to
prevent the barrel from being overheated by the fluid cast iron. This is
poured down vertical channels from the top, which channels enter the mould
in the first instance at the bottom, and subsequently at different heights as
the mould fills up; these channels enter the mould in a tangential or slanting
direction in order to prevent the fluid metal from impinging on the barrel, as
described in the Specification to my before-mentioned Letters Patent. Upon
the outer surface of the breech end of the barrel I form a shallow screw
thread or series of rings into which the cast iron enters in order that the
extension of the B tube due to the heating of the same shall take place
towards the muzzle, and thus enable the cast iron to lie close up against the
breech end of the barrel. The B tube is connected to the A tube by pinuing
or otherwise in order to prevent the B tube when expanded off the A tube
by the heat from sinking down in the fluid cast iron owing to its greater
specific gravity. A screw thread or series of rings is cut upon the outer surface
of the A tube immediately in front of the end of the B tube in order that.
the cast iron may run into the grooves and thus retain the tube in its place
in the same manner as is effected by the before-mentioned screw collar in the
converted guns.
I subsequently screw a breech plug or cascable, by pre-
ference of wrought iron, through the cast iron and into a relieved female
screw thread cut in the breech end of the B tube, such breech plug or,

page_text: cascable being made to bear up against the end of the A tube, which is closed
with either a separate plug or with a cup, as herein-before described. The
cascable is thus of smaller diameter than the bore of the B tube although
larger than that of the A tube. A helical indicator channel may be formed
in the barrel, as before described.
Another improvement consists in forming at the termination of those
female screw threads that are not formed in relief in the tubes, as also the
'female screw threads cut in the breech-end of the cast-iron casing, a circular
channel by preference of a curved transverse section, which serves to prevent
the rupturing of the tube or gun at the last thread of the screw.
Another part of my Invention has reference to the rifling of guns generally.
I cause the rifle grooves to terminate at a distance from the breech ond of the
bore equal to about one and a half times the space occupied by the heaviest
battering charge of powder which the gun is intended to fire in order to
enable the pressure of the gases to be considerably diminished before reaching
that part of the barrel which is weakened by the rifle grooves. These grooves
commence with a very slow uniform (i.e., unaccelerated) twist, such twist
being so slow that the pressure of a single stud on the projectile in cach
groove will not cause any injury to the driving edge thereof. At a certain
distance, which in most guns will amount to about two feet from the breech
end of the grooves, the twist becomes accelerated by preference in such a
manner that if the bore of the gun were laid out flat the accelerated portion
would form an arc of a circle, to which the unaccelerated portion would be a
tangent. The projectiles for this form of rifling are fitted with only one stud,
by preference of gun metal, for each groove, which in place of being arranged
round the centre of gravity of the projectile, as described in the Specification
to my before-mentioned Patent, are placed at the front extremity of the
cylindrical part of the same in order to enable the projectile to pass as far as
possible down into the smooth portion of the barrel. I prefer to round off
the rear edges of the projectiles to a radius of about three-quarters of an inch
in order to facilitate the loading. It is essential where the rifling is stopped
short, as before described, and the projectiles are provided with studs towards
their front ends, that the rifling should at- first be unaccelerated, since with
heavy charges of powder and long projectiles, as, for instance, double shells,
the front studs would otherwise damage the rifling owing to their initial
contact with the driving edges of the grooves at a place where the twist
has already become considerably accelerated.
Another part of my Invention has reference to the manufacture of "chilled,”
or, as they are termed, "Palliser" projectiles. My improvement consists in

page_text: casting the projectile with a portion of the cylindrical body of less diameter
than the ends thereof. This is effected by enlarging the chills at the two ends..
of the cylindrical portion to only such a depth that the contraction of the.
projectile will allow it to deliver from the chill when cast. The object of this
improvement is, that as it is found essential to good shooting that the body of
the projectile should be perfectly cylindrical, it is necessary to grind the same.
or turn it in a lathe at a very slow speed, whereby the expense and difficulties.
of manufacture are greatly increased; whereas by the above improvement a
comparatively small portion only of the projectile has to be so treated..
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Palliser in the Great Seal Patent Office on the
10th June 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
PALLISER, Major Unattached, of the Army and Navy Club, Pall Mall, in the
County of Middlesex, send greeting.
WHEREAS IIer most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of December, 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 William Palliser, Her special licence, that I, the said William Palliser,
my executors, administrators, and assigns, or such others as I, the said William
Palliser, 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 IN PROJECTILES USED THEREWITH, AS ALSO THE PROCESSES EMPLOYED IN THEIR
MANUFACTURE," upon the condition (amongst others) that I, the said William.
Palliser, my executors or administrators, by an instrument in, writing under:
my, or their, or one of their bands 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 sail Letters Patent.
NOW KNOW YE, that I, the said William Palliser, do hereby declare.the
nature of the said Invention, and in what manner the same is to be per..

page_text: formed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the accompanying Drawings, and to
the figures and letters marked thereon, that is to say :-
My Invention relates,―
Firstly. To improved modes of strengthening or "converting " existing
cast-iron guns.
Secondly. To an improved mode of constructing compound guns composed
of a combination of steel, wrought iron, and cast iron, as also to improvements.
in the processes employed in their manufacture.
Thirdly. To an improved system of rifling guns.
And, lastly. To improvements in the form and manufacture of projectiles
therefor.
One of my improvements relating to the conversion of existing cast-iron
guns in which a wrought iron or steel lining or barrel is introduced through
the muzzle, as described in the Specification to certain Letters Patent
granted to me, and bearing dato the 11th November 1862, No. 3038,
consists in forming the breech portion of the lining or barrel with two tubes,
of which the inner or "A" tube is comparatively thin, and is constructed
either of steel of such a quality as will stretch or of coiled wrought iron,
which tube I fit into a seat formed in the outer or "B" tube, which extends
the entire length of the barrel, and which may also be either of steel or of
coiled wrought iron.
.
Or, in another arrangement, I make the A tube of the entire length of
the barrel, and I reduce the thickness of the breech end thereof externally,
and I fit the "B" tube over such reduced end of the "A" tube. In large
guns, where it not practicable to make the muzzle end of the A tube of
such a thickness as to be equal in diameter to the combined thickness of the
"A" and "B" tube at the breech, I increase it up to the required size by fit:ing
upon it pipes or tubes of cast or wrought iron, which in the case of short
guns or howitzers may project together with the inner barrel a sufficient
distance beyond the muzzle of the gun to make the converted gun of the
required length. The object of making the "A" tube thin at the breech end
is, that should the barrel split by the action of long continued firing, which it
is liable to do, such split would not extend beyond the A tube, and would in
consequence only be shallow, and thus the mechanical advantage gained by
the internal pressure of the gas by means of such shallow split would not be
sufficient to burst the thick B tube supported by the cast-iron casing. It is
essential when the barrel is composed of two tubes throughout, as last
described, that the screw collar or screw washer at the muzzle, described

page_text: in the Specification to my before-mentioned Letters ratent,, should secure
the inner tube as well the outer one.
Another improvement consists in cutting a liclical channel' of a quick pitch
either round. the external surface of the A tube or in the internal surface of
the B tube, which channel communicates with an indicator hole that passes
out through through the breech end of the gun. The object of this arrangement
is, that should the A tube split the gas escaping through such split will at onco
find its way through the helical channel to the indicator hole,, and thus give.
warning to the detachment serving the gun..
Another improvement consists in forming the cup closing the end of the:
barrel of a ring of steel or wrought iron, which is converted into a cup by
means of a plug of steel or wrought iron screwed into its centre from the
inside with a countersunk head..
Another improvement has reference to the vents' of guns generally, and:
consists in running the screw thread down the entire length of the bush into
the bore of the gun instead of coning the lower end as heretofore, and com-
bining with such bush an interior tubular lining of platinum or alloy of
platinum screwed into the lower end of the said bush, which lining, as also
the end of the bush into which it is screwed, may or may not have a counter-.
sunk head formed upon it..
In constructing new compound guns I cast a casing either solid or hollow
in the former case I bore it out and line it with a compound coiled wrought
iron or steel barrel, in a similar manner to that described with reference to.
my couverted guns; in the latter case the core may extend right through the
casing, in which case, after inserting the barrel, I close the breech end of the
gun by means. of a wrought iron or steel cascable or breech plug, such.
cascable being made to screw through the cast iron and into the B tube, the
tbreads of which are in relief. By this means the front threads of the plug,
which transfer the greatest pressure to the female screw threads, transfer such
pressure to screw threads of wrought iron or steel instead of cast iron.
Since filing my Provisional Specification I have found that the system
there described of casting a cast-iron casing upon a wrought iron or steel
barrel is not practicable, and I therefore do not claim such system as part of.
my Invention.
Another improvement consists in forming at the termination of those
female screw threads that are not formed in relief in the tubes, as also the
female screw threads cut in the breech end of the cast-iron casing, a circular
channel by preference of a curved transverse section, which serves to prevent
the rupturing of the tube or gun at the last thread of the screw by throwing..

page_text: the screw thread well into relief, thereby making a portion of the casing or
tube of less strength than the screwed part in order that any extension
thereof due to the longitudinal strain on firing may not occur at such screwed
part.
Another part of my Invention has reference to the rifling of guns generally.
I cause the rifle grooves to terminate at a distance from the breech end of
the bore equal to about one and a half times the length of the cartridge con-
taining the heaviest battering charge of powder which the gun is intended to
fire in order to enable the pressure of the gases to be considerably diminished
before reaching that part of the barrel which is weakened by the rifle grooves.
These grooves commence with a very slow uniform (i.e., unaccelerated) twist,
such twist being so slow that the pressure of a single stud on the projectile
in each groove will not cause any injury to the driving edge of the grooves.
At a certain distance, which in most guns will amount to about two feet from
the breech end of the grooves, the twist becomes accelerated by preference in
such a manner that if the bore of the gun were laid out flat the accelerated
portion would form an are of a circle, to which the unaccelerated portion
would be a tangent. I term this system of rifling "partially accelerated,"
inasmuch as it is a combination of the uniform and accelerated systems of
rifling. The projectiles for this form of rifling are fitted with only one stud,
by preference of gun metal, for each groove, which in place of being arranged
round the centre of gravity of the projectile, as described in the Specification
to my before-mentioned Patent, are placed at the front extremity of the
cylindrical part of the same in order to enable the projectile to pass as far as
possible down into the smooth portion of the barrel. I prefer to round off
the rear edges of the projectiles to a radius of about three-quarters of an inch
in order to facilitate the loading. It is essential where the rifling is stopped
short, as described, and the projectiles are provided with studs towards their
front ends, that the rifling should at first be unaccelerated, since with heavy
charges of powder and long projectiles, as, for instance, double shells, the
front studs would otherwise damage the rifling owing to their coming into
contact at first starting-with the driving edges of the grooves at a place
where the twist Las already become considerable accelerated, in which, since
the motion of translation of the projectile is at first highly accelerated, the
result would be injurious to the groove.
"
Another part of my Invention has reference to the manufacture of
chilled," or, as they are termed, "Palliser" projectiles. My improvement
consists in casting the projectile with a portion of the cylindrical body of
Joss diameter than the ends thereof. This is effected by enlarging the chills

page_text: at the two ends at the cylindrical portion to only such a depth that the
contraction of the projectile will allow it to deliver from the chill wben cast.
The object of this improvement is, that as it is found essential to good
shooting that the body of the projectile should be perfectly cylindrical, it is
necessary to grind the same or to turn it in a lathe at a very slow speed,
whereby the expense and difficulties of manufacture are greatly increased;
whereas by the above improvement a comparatively small portion only of the
projectile has to be so treated.
On the accompanying Drawings are shown various arrangements for
carrying my before-described improvements in ordnance and projectiles into
effect.
. Figure 1 on Sheet I. shows a longitudinal section of a converted cast-iron
gun C, into which after it has been bored out to the required extent is
inserted the lining or barrel composed of the tube A of steel or coiled wrought
iron extending the whole length of the bore, the breech end of which is.
reduced in thickness so as to form a comparatively thin tube at that part, as
shown, and upon the exterior of which reduced part is fitted the tube B.
Figures 2 and 3 show a modification of this arrangement for large guns,
where the muzzle end of the A tube not being made equal in thickness to the
combined A and B tube at the breech end the muzzle end of the barrel is
built up to the required diameter by means of one or more pipes D, D', of
either wrought iron, as at Figure 2, or of cast iron, as at Figure 3, fitted on
to the exterior of the A tube, and such cast-iron pipes or tubes may be made
to project with the A tube beyond the muzzle of the gun, as shown at
Figure 4, which arrangement I should adopt for converting cast-iron howitzers,
which are very short but thick; in this case the cast-iron D tube described
with reference to Figures 2 and 3 projects with the barrel a considerable
distance beyond the muzzle of the casing, and thus gives the required length
for the bore. This pattern is also well suited for the manufacture of new
guns of large calibre.
In all these arrangements after the barrel is inserted it is secured in its
place by means of the screw collar E, which screws into a female screw cut
in the muzzle of the cast-iron gun C, and in the arrangement at Figure 1
abutts against a shoulder a formed on the A tube, while in the arrangements
Figures 2 and 3 it abutts against a shoulder a formed on the tube D¹, which in
Figures 2 and 3 holds the A tube by abutting with its inner end against a
shoulder a' formed on the latter, while in Figure 4 the A tube is held by a
second screw collar E' screwed into D' and abutting against a shoulder a' on
the A tube. Between the outer surface of the A tube and the inner surface

page_text: of the B tube, in Figures 1, 2, and 3, is formed the helical channel b, which is
either cut in the outer surface of the A tube, as shown at Figures 1 and 3, or
in the inner surface of the B tube, as at Figure 2. This channel communi-
cates at the breech end with the indicator hole c passing through the breech
of the gun, so that if the A tube should split at any point the escaping gas
will find its way through the channel 6 to the indicator hole c,, and thus give
warning to the men serving the gun. In Figure 4 a short inner tube or
"chamber liner "A being fitted into the recessed rear end of A the channel b
is cut in the outer surface of A'. The rear end of the A tube, Figures 1, 2,
and 3, and of the tube A', Figure 4, is closed by means of a cup F composed
of a ring of steel or wrought iron, into the centre of which a plug f, also of
steel or wrought iron, is screwed from the inside with a countersunk head.
The female screw of the A tube into which the cup is screwed is formed in
r.lief upon the tube as and for the purposes described in the Specification to
my before-mentioned Letters Patent. The inner bottom surface of the cup F
is formed flat, the sharp edges of the sides being rounded off; the walls of the
cup are by preference cylindrical, since if the cup were couical.with a rounded
bottom (which form is commonly known as the "gomer" chamber) the action
of the gas would quickly cat a hole into it. The end of the B tube has also a
relieved female screw, into which is screwed the breech plug G so as to press
against the end surfaces of the tubes A or A¹ and cup F. The bush forming
the vent H of the gun is screwed along its entire length, as shown, and has at
its inner end a tubular lining h of platinum or alloy of platinum screwed into
it with a countersunk head, the inner end of the bush being also by preference
countersunk by being rivetted up in a conical seat after insertion, as shown
more clearly in the enlarged section at Figure 5, which also more clearly
shows the cup F and the rounded form of screw thread which I prefer to
employ.
Figure 6, Sheet II., shows an arrangement in which the B tube is maile
of the entire length of the barrel instead of the A tube, as in the previous
arrangements; it is recessed internally at the breech end, and into the recessed
portion is fitted the thin A tube, the bevilled front end of which is forced
against the bevilled shoulder of the B tube by means of the breech plug G
screwed into the latter. As the screw thread cannot in this case be made in
relief upon the B tube, a circular groove g is cut at the bottom of the screw
thread, in order to prevent the rupturing of the gun from longitudinal strains,
which might otherwise take place at the last thread of the screw. A similar
groove e is also formed for the same purpose in all cases at the bottom of the
female screw thread cut in the muzzle of the cast-iron gun C, into which the

page_text: screw collar E is screwed for securing the barrel. II is the vent with platinum
lining h; F, the cup closing the A tube. In this case the old vent of the
gun is closed by a solid screw plug, as shown, and the new vent H is made
farther forward, so as not to pass through the cup F; this latter is also made
of considerably less depth than in the other arrangements.
Figure 7, Sheet II., shows the same arrangements of A and B tubes as
Figure 6, in which however the breech end of the B tube does not project
beyond the A tube, the plug G being dispensed with, and the A tube
and cup F brought against the end of the bore of the cast-iron gun.
In all the before-described arrangements I prefer to introduce the barrel
into the gun in the following manner: I boro a cylindrical holo in the
gun or casing of a slightly larger diameter than that of the barrel, so that the
latter may enter. it with a loose fit. The barrel being placed in the gun
before the former is bored to the finished size I then set it up inside the
casing so as to fit tightly into it by firing heavy proof rounds from the gun;
after which I fine bore the barrel to the required size, thus removing the
bulge formed in the powder chamber by the firing; or I boro out the cast-
iron casing slightly conically for a certain distance at the breech end, say, two
or two and a half feet, and the remainder I bore out cylindrically. The
barrel is then turned with a corresponding conical part at the breceh end so
as to fit the conical part of the casing, and with a cylindrical part at the
muzzle end rather too large for the cylindrical part of the casing, after which
the cast-iron casing is heated so as to be slightly expanded, and the barrel is
then dropped into its place.
Figures 8 and 9, Sheet II., show longitudinal sections to a smaller scale of
two arrangements of my improved compound gun, in which a cast-iron casing
C is cast in the manner before described, into which the wrought iron or steel
tubes A and B forming the barrel are then inserted from the muzzle.
In both arrangements the cast-iron casing C is cast hollow throughout.
After having been bored a barrel is fitted into it composed of the A tube,
extending the whole length of the bore, and the short B tube on the breech
end of the A tube, other cylinders D of wrought or cast iron of equal
diameter with the B tube being fitted on the muzzle end of the A tube in a
similar manner to the arrangements of converted guns described at Figures 2
and 3; the barrel is also secured in the casing by a screw collar E screwed
into the muzzle in precisely the same manner as described with reference to
those arrangements. In the arrangement at Figure 8 a chamber liner A' is
furthermore fitted into the breech end of A, and an indicator channel 6 is, as
before, formed between the tubes A, A', in this case, and between the tubes A

page_text: and B in Figure 9. The breech end of the A tube in Figure 9 and of the
chamber liner A' in Figure 8 is closed by a screw cap F, constructed as
before described, and screwed into relieved screw threads formed in the tubes,
while the breech end of both the cast-iron casing C and of the B tube is
closed by a breech plug or cascable G of wrought iron or steel of larger
diameter than the bore of the gun, which is screwed through the casing C
and into the B tube, so as to bear against the end of the A tube. By this
mcans, as before stated, the greatest strain received by the cascable on firing
is transferred to the wrought iron or steel female threads of the B tube. H
is the screwed vent provided, as in the other arrangements, with a platinum
lining s rewed into the lower end.
My improved system of rifling is shown at Figure 7 and in the Diagram
at Figure 10. The rifle grooves L start from a point just beyond the termi-
nation of the A tube; they commence with a uniform twist by preference
equal to about one turn in a length of one hundred calibres, proceeding thus
to the point a distance of about four calibres, from which point the twist is
accelerated in the form of an are of a circle 1, 1, Figure 10, so as at the
muzzle of the gun to have attained a pitch equal to one turn in forty calibres.
This is seen more clearly in Figure 10 where the lines W, X, Y, Z, represent
the bore of the gun with one of the rifle grooves L developed on a plane
surface.
Figures 11, 12, and 13 show my before-described improve construction of
projectiles.
Figure 11 shows a projectile I, having a ring of studs i, i, placed at the
front extremity of the cylindrical part, there being only one such stud to each
rifle groove of the gun in order to enable the projectile to pass as far as
possible into the smooth portion of the barrel in my before-described improved
system of rifl'ng, as indicated at Figure 4. The rear edge of the projectile is
by preference rounded off to the extent more clearly shown in the full-sized
detail at Figure 12 in order to facilitate loading.
Figure 13 shows the improved form of "Palliser" projectile in which the
middle portion of the cylindrical art is cast of a somewhat less diameter
than the two end portions 4, 7, the difference of diameter being however
ouly such, that the parts k, l, of the projectile on contracting after being
cast will deliver from the smaller diameter of the chill for the part k. By
this arrangement it is only necessary to grind the bands h, k, in order to
obtain a perfect fit of the projectile. i, i, are, as before, gun-metal studs fixed
on the front end of the cylindrical part.
Having thus described the nature of my Invention, and in what manner

page_text: the same is to be perforined, I wish it to be understood that I do not limit
myself to the precise combinations of my several improvements as hercin-
before described with reference to the accompanying Drawings, as several of
such improvements may be employed separate and apart from tho others; but
what I claim under the berein-before in part recited Letters Patent is,-
First. Constructing the barrels introduced at the muzzles of converted
cast-iron guns of two tubes, at the breech end of which the inner or A tube
is made comparatively thin, substantially as and for the purposes herein-before
set forth.
Second. Constructing the barrels of converted cast-iron guns with an outer
or B tube at the breech end of a larger external diameter than the muzzle
end of the inner or A tube, and placing upon such muzzle end of the A tube
cylinders of equal diameters with or larger than the B tube, substantially as
and for the purposes herein-before set forth with reference to Figures 2, 3,
and 4 on the accompanying Drawings.
Third. Forming a helical channel between the inner and outer tubes at the
breech end of the barrel of converted and compound guns in communication
with an indicator hole passing through the breech of the gun, substantially as
and for the purposes described.
Fourth. Constructing the cup closing the end of the barrel of converted
and compound guns, substantially as herein-before set forth.
Fifth. Forming the bushes of the vents of guns with a screw thread along
their entire length, and combining therewith a tubular lining of platinum or
alloy of platinum screwed into the lower end of the vent, substantially as
described.
Sixth. Constructing new compound guns of a casing of cast iron, into which
a coiled wrought iron or steel barrel is inserted from the muzzle end, in the
manner herein-before set forth.
Seventh. Closing the breech end of compound guns with a wrought iron
or steel breech plug or cascable of larger diameter than the bore of the gun,
screwed through the cast-iron casing and into the breech end of the B tube,
substantially as and for the purposes herein-before set forth.
Eighth. Forming an annular groove at the end of those screw threads
that are not formed in relief in the tubes or casing, substantially as and for
the purposes herein-before set forth.
Ninth. The improved system of rifling guns with partially accelerated
grooves which do not extend into the powder chamber, substantially as
herein-before described.

page_text: Tenth. Providing projectiles with studs at the front extremity of the cylin-
drical part only in combination with a rounded base, substantially as and for
the purposes herein-before set forth.
Eleventh. Forming chilled or "Palliser" projectiles with the middle portion
of the cylindrical part of a less diameter than the two ends, substantially as
and for the purposes herein-before set forth.
In witness whereof, I, the said William Palliser, have hereunto set
my hand and seal, this Ninth day of June, in the year of our Lord
One thousand eight hundred and sixty-eight.
Witness,
CHAS. D. ABEL.
W. PALLISER. (L.S.)