CRIPTION OF THE INVENTION.
Year: 1892

page_text: Date of Application, 29th July, 1892
Complete Specification Left, 28th Apr., 1893-Accepted, 1st July, 1893
Lieut.-Colonel HENRY ELSDALE Royal Engineers Royal Engineer Office
Exeter does hereby declare the nature of this invention to be as follows:-
DESCRIPTION OF THE INVENTION.
1. The gun when not required for action, consists of a light barrel only. The
breech is detachable and can be stowed away separately. The projectile is inside
t and goes with it. When required for action the breech or removable part is
fixed to the gun by an interrupted screw a see Fig. 1, and thereby is locked in
position for firing.
2. The charge or propelling power consists primarily of compressed air confined
in an enlarged chamber forming when thus attached by the interrupted screw, the
breech of the gun. The initial impetus given by the compressed air is then main-
tained or increased in the flight of the projectile by a powerful rocket, which forms
the base or hinder portion of the projectile.
3. In order to prevent distortion or bending of the light barrel of the gun two
or four ribs or raised flanges (b, see Figs. 1 and 4) may be formed on the chase
of the gun.
4. There are no trunnions on the gun. It slides easily backwards and forwards
on a horizontal path consisting of ball bearings or friction rollers on each side,
running on a portion of the raised flanges, as shewn at c, e Figs. 2 and 4.
Thereby the gun is free to move longitudinally through a suitable portion of its
length within a trunnion ring, shewn in section in Fig. 4, the free revolution of
which on a turntable below provides for the traversing of the gun.
With large guns friction rollers or ball bearings may also be provided at the
sides of the trunnion ring for the projecting flanges to slide upon, so as to obviate
lateral friction.
5. In the front or normal position of the trunnion ring, the unloaded gun or
barrel is balanced at or near its centre of gravity, and there securely locked, as by
simple self-acting pawls or stops. When required for action these locking bolts
are released, and the gun run forward on the ball bearings till it reaches a similar
set of locking bolts or stops at the rear end of the roller path. These then lock it
for firing.
6. When the chamber or breech has been fixed on by the interrupted screw the
gun is again balanced on the trunnion ring, with only such small preponderance as
may be desired. A. breech elevating gear of any approved pattern will be provided
for the elevation. This will be fixed to the rear end of the gun and prevent its
revolving forward when the weight of the chamber is removed. The bearing or
support of the breech elevating gear will "slide" forward and be drawn out or in
together with the gun.
7. A section of the hinder portion of the rocket projectile is given in Fig. 3.
The rocket case which is very strong in tough steel, may preferably be cast
together with, and form part and parcel of, the shell, or front portion of the
projectile. Or it may if desired be screwed permanently into it. The rocket
portion, or rear end of the projectile is accurately fitted in front to the collar or
aperture of the steel chamber." Below the collar it should be an easy fit, and be
well lubricated, so as to slide easily through the collar.
8. There are no external valves or fittings of any kind to the air chamber, but

page_text: there is a small internal air valve, whereby it can be loaded with the compressed
air. The air-tight joints provided for this purpose are shewn in detail in Figs. 5
and 6. The air-tight joint in each case is formed of a circular collar of pure soft
lead, or other approved soft metal. This is compressed on all sides against the
steel of the projectile or chamber, and thereby retained firmly in position, while
raised circular projecting ribs or flanges turned on the steel surface of the projectile
itself (shewn in section in the figures) are forced into the lead under any required
pressure, so as to consolidate it into an impermeable substance, in which the
projecting ribs of steel are firmly bedded.
9. The chamber is provided with an inside cylinder (d Figs. 1 and 3). This
may be slightly coned or tapered for a suitable distance at its rear end, to fit a
similar slightly coned surface on the rear end of the exterior of the rocket. The
lower or coned portion of the exterior of the rocket may also be lead-coated
in order that it may take a better and more even bearing on the cylindrical
collar, and to prevent the possibility of the projectile jamming or sticking fast in
its seat.
10. Fig. 3. shews the arrangement by which the rocket projectile is secured in
its seat. This consists of a strong solid bolt e, which passes through the centre of
the base of the chamber, and terminates inside in a cylindrical ring of steel, which
is provided with an interrupted screw. This engages in a female screw in the base
of the outer case or cylinder of the rocket, which is prolonged beyond the base
plug for the purpose. When this safety bolt is disengaged the projectile is cleared
for firing.
11. The rocket composition (g Fig. 3) is fired by the spark from an ordinary
firing tube or detonator fixed in a small cylindrical hole in the centre of the safety
locking bolt. The strong spark from the firing tube pierces a small silk bag of
fine grain powder & fixed directly in front of it in a central hole in the base plug of
the rocket. When the projectile has moved a suitable small distance the base
of the exterior cylinder of the rocket will clear the lower edge of two equal longi-
tudinal slots cut in the cylindrical support, or inner cylinder of the air chamber
(see Fig. 7 which shows the arrangement in side elevation) and the compressed air
will pour in behind the rocket from two sides at once. As the rocket projectile
travels forward it gradually gains the full benefit of the driving pressure of the
compressed air directly behind.
12. The construction of the air chamber is shewn in Fig. 1. The longitudinal
strain upon it, due to the air pressure, is largely reduced, as compared with the
radial or bursting strain by the space taken up by the rocket, and by the steel
collar or inner cylinder which surrounds the rocket. Also the latter acts as a
strong central support to the air chamber, and takes part of the longitudinal
strain. The available section of this inner cylinder, after deducting the portion
cut away by the two longitudinal slots or air channels shewn in Fig. 9, is so
proportioned as compared with the thickness of the exterior cylinder of the air
chamber, that a suitable proportion say one half, of the steel of the latter on
the inside is sufficient for the required longitudinal strength. Then the remainder,
or outer half, may be devoted to a wire-wound jacket of ribbon steel, which
gives the strongest construction for resisting the bursting pressure of the
compressed air.
13. An incombustible non-conducting lining to the rocket case, preferably of
compressed asbestos, is shewn at i Fig. 3. This is introduced between the rocket
and its steel case, and between the base of the shell and the head of the rocket. It
tends to prevent or retard the heating up of the metal case of the rocket by the
burning of the composition.
14. A. side elevation of the breech of the gun is given in Fig. 8, shewing the
combined bolt withdrawing and firing lever k, of which details are given in Figs. 9
and 10. Referring to these figures it will be seen that the firing lever has a
heavy ball at the handle, and can be rotated by hand freely and rapidly, until the
fixed stops, come in contact with the corresponding stops m, m, which are flanges

page_text: on the outer end of the safety locking bolt. Then the momentum of the weighted
handle of the lever is available to overcome the initial resistance to rotation of the
threads of the interrupted screw on its inner surface engaged in the rocket case,
and a further turn of th or th of the circle will disengage it.
thereupon a strong circular coiled spring of ribbon steel (seen in section
Immediately
at n, n Fig. 3) comes into play. It will press the whole bolt and its attachments
back with a sudden start. This will be a signal to the gunner that the rocket is
actually disengaged, and he can thereupon cock the percussion lock for firing. This
lock slides into grooves on the firing lever, or is otherwise readily attached to or
removable from it. During practice it can remain a fixture on the lever and
revolve with it.
15. A special construction of the interrupted screw of the safety locking bolt is
shewn in Fig. 11. The interrupted threads do not run right round the bolt with
the usual intervals. A small solid portion of steel remains on the left side of each
segment, supposing the screw to move from left to right in locking. When the
bolt is disengaged this continuous surface of steel on the left face of each moving
segment will then come in contact with the right hand side of each fixed segment.
Hence the overriding of the segments or burring up of their edges under a powerful
stroke of the turning lever will be avoided.
screw to be thus left solid may be slotted away, if desired, together with the
In construction the portion of the
adjoining interval, and a longitudinal piece of steel fixed in its place in an undercut
groove as shewn in the section.
16. The firing lever is suspended as shewn on Fig. 8, from a small rotating
traveller, or hoist o, above the breech of the gun. Before the chamber is put in
position, the traveller can be turned round sideways through 180°, or any lesser
angle, to a forward position out of the way. After the chamber is locked on it can
be swung round to its front position as shewn on the drawing. When not required
for action it can be easily and quickly dismantled and stowed away. This traveller
suspends the weight of the firing lever, and retains it in its right place exactly
opposite the centre of the gun. The centre or supporting pivot of the traveller is
a little to the right or left of the centre of the gun, that it may not prevent an
uninterrupted view along the centre line.
17. The rear end of the exterior of the gun itself is prolonged below to form a
projecting bracket or shelf (see Fig. 8), on which the chamber rests, as far back as
a point behind its centre of gravity. Hence the weight of the chamber is taken
by the bracket, and the jamming of the threads of the interrupted screw, by the
weight of the chamber hanging upon them, is prevented.
FEATURES OF NOVELTY CLAIMED IN THIS INVENTION.
The following points are claimed as new in this invention :—
(a) The method or arrangement whereby the breech o breech chamber of the
gun, containing the projectile and its propulsive power, is detachable from the gun,
nd can be fixed or removed as required, substantially as shewn in the drawings.
(b) The combination of a charge of compressed air, to give initial propulsion to
he projectile, with a powerful rocket to maintain that initial impetus during its
ight.
(c) The method or arrangement or combination whereby the usual provision of
eparate air pumps or compressors, or air storage reservoirs or cylinders permanently
ttached to, or forming part of each individual gun, for the purpose of liberating an
ssigned portion of compressed air for the pneumatic propulsion, is avoided.
In
is system all the air chambers for the same description of gun are separate,
milar and interchangeable. Hence any required number of them can be assigned
any one gun, or forthwith removed to any other gun, just as is done with the
artridges and shells of ordinary powder guns. And each projectile has attached
it, independantly of the gun. its own proper charge of compressed air, and
more.

page_text: (d) The method of dispensing with fixed trunnions on the gun by causing it to
slide easily through a given portion of its length on a roller path, running within a
separate trunnion ring, substantially as shewn on the drawings, and explained under
par. 4 above.
(e) The combination whereby raised flanges which serve to strengthen the gun
laterally, serve also for the bearings of the sliding roller path.
() The method or arrangement whereby the gun is balanced at or near its
centre of gravity, with only such small preponderance as may be desired both with
and without its breech chamber, by aid of the sliding roller path and separate
trunnion ring, as explained under par. 5 and 6 above.
(7) The method or arrangement whereby the traversing of the gun is provided
for by the revolution on a turntable of a separate trunnion ring through which the
gun slides as described.
(4) The method or combination whereby the bearing or support of the breech
elevating gear slides backwards and forwards, while the gun itself slides corre-
spondingly backwards and forwards within its trunnion ring, as explained in par. 6
above.
(i) The combination whereby the projectile itself fills up the aperture or inouth,
and the entire central portion of the air chamber, and forms its own joints to retain
the compressed air, whereby all ordinary valves or moveable fittings to retain it
are avoided and this without any permanent forward driving pressure on the
projectile, substantially as shewn on the drawings.
(j) The method or arrangement whereby the air chamber for the compressed air
forms the breech of the gun itself, substantially as shewn.
(A) The special construction of the air chamber, or combination consisting of an
outer and an inner cylinder to retain the compressed air, with slots in the inner
cylinder for its exit, while the inner cylinder forms a strong central bolt to support
the chamber against the longitudinal strain due to the compressed air, substantially
as shewn on the drawings and explained above.
(m) The special construction of the air-tight joints between the air chamber and
projectile to retain the compressed air, substantially as shewn on the drawings and
explained above in par. 8.
(a) The method or combination whereby the rear end of the projectile is slightly
coned and lead coated, substantially as explained in par. 9 above.
(0) The method or combination whereby the projectile is secured in its seat by a
safety locking bolt passing through the centre of the base of the air chamber,
which bolt can be actuated from the outside to set the projectile free, substantially
as explained in par. 10 above.
(p) The method or combination whereby the rocket composition is fired by the
spark from an ordinary firing tube or detonator fixed in a suitable cylindrical
hole in the centre of the safety locking bolt, substantially as explained in par. 11
above.
(g) The method or combination whereby the projectile, after moving a given
distance from its seat, gradually gains the driving pressure of the compressed air
pouring in behind it through the longitudinal slots in the inner cylinder of the air
chamber, substantially as explained in par. 11 above.
(r) The method or arrangement of inserting an incombustible non-conducting
lining inside the rocket case, to retard its heating up by the burning away of the
composition as explained in par. 13 above.
(s) The special construction of the firing lever, whereby the acquired momentum
of a heavy ball or weighted handle is made available to overcome the initial
resistance to turning of the interrupted screw of the safety locking bolt, substan-
tially as explained in par. 14 above.
(t) The combination whereby the lever which actuates the safety locking bolt
for its release is also the firing lever which carries the lock or firing apparatus,
substantially as explained in par. 14 above.
(u) The method or combination whereby the release of the safety locking bolt

page_text: is indicated to the eye of the gunner who works the gun, by the release of a
circular coiled spring, substantially as explained in par. 14 above.
(") The special construction of the interrupted screw of the safety locking bolt,
whereby a small solid portion of steel is fixed on the inside of each moving segment,
substantially as explained in par. 16 above.
(w) The combination whereby the firing lever is suspended from a rotating
traveller or hoist above, which carries its weight, and holds it in position for its
work, substantially as explained in par. 16 above.
(a) The method of prolonging the rear end of the gun on the under side to form
a projecting bracket or shelf on which the chamber rests to a point behind its
centre of gravity, so as to prevent the jamming of the threads of the interrupted
screw by the weight and backward leverage of the chamber, as explained in par. 17
above.
Signed, at Exeter, this 27th day of July 1892.
H. ELSDALE,
Lt.-Colonel, R.E.
New or improved Pneumatic Rocket Gun.
I Lieutenant-Colonel HENRY ELSDALE Royal Engineers at present of
Trelawney, Pietermaritzburg, Natal permanent address c/o Messrs. Cox and Co.
Charing Cross London do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
Reference is to be made to the drawings filed with my Provisional Specification.
1. The gun when not required for action, consists of a light barrel only. The
breech is detachable, and can be stowed away separately. The projectile is inside
it and goes with it. When required for action the breech or removable part is
fixed to the gun by an interrupted screw a, see Fig. 1, and thereby is,locked
in position for firing.
2. The charge or propelling power consists primarily of compressed air confined in
an enlarged chamber forming, when thus attached by the interrupted screw,
breech of the gun.
the
The initial impetus given by the compressed air is then
maintained or increased in the flight of the projectile by a powerful rocket, which
forms the base or hinder portion of the projectile.
3. In order to prevent distortion or bending of the light barrel of the gun, two
or four ribs or raised flanges (b, see Figs. 1 and 4) may be formed on the chase
of the gun.
4. There are no trunnions on the gun. It slides easily backwards and forwards
on a horizontal path consisting of ball bearings or friction rollers on each side,
running on a portion of the raised flanges as shewn at c, c Figs. 2 & 4. Thereby
the gun is free to move longitudinally through a suitable portion of its length
within a trunnion ring, shewn in section in Fig. 4, the free revolution of which on
a turntable below provides for the traversing of the gun.
rollers or ball bearings may also be provided at the sides of the trunnion ring for
With large guns, friction
the projecting flanges to slide upon, so as to obviate lateral friction.
5. In the front or normal position of the trunnion ring the unloaded gun or barrel
is balanced at or near its centre of gravity, and there securely locked, as by simple
self acting pawls or stops. When required for action these locking bolts are
released, and the gun run forward on the ball bearings till it reaches a similar set
of locking bolts or stops at the rear end of the roller path. These then lock it for
firing.
6. When the chamber or breech has been fixed on by the interrupted screw the
gun is again balanced on the trunnion ring, with only such small preponderance as

page_text: may be desired. A breech elevating gear of any approved pattern will be provided
for the elevation. This will be fixed to the rear end of the gun and prevent it revolving
forward when the weight of the chamber is removed. The bearing or support of
the breech elevating gear will slide forward and be drawn out or in together with
the gun.
7. A section of the hinder portion of the rocket projectile is given in Fig. 3. The
rocket case, which is very strong in tough steel, may preferably be cast together
with, and form part and parcel of, the shell, or front portion of the projectile. Or
if desired, be screwed permanently into it. The rocket portion, or rear end
of the projectile, is accurately fitted in front to the collar or aperture of the steel
air chamber. Below the collar it should be an easy fit and be well lubricated, so as
to slide easily through the collar.
it may,
8. There are no external valves or fittings of any kind to the air chamber, but
there is a small internal air valve whereby it can be loaded with the compressed air.
The projectile forms its own valve to retain the compressed air. The air-tight
joints provided for this purpose are shewn in detail in Figs. 5 and 6. The air-tight
joint in each case is formed by a circular collar of pure soft lead, or other approved
soft metal. This is compressed on all sides against the steel of the projectile or
chamber, and thereby retained firmly in position, while raised circular projecting
ribs or flanges turned on the steel surface of the projectile itself (shewn in section
in the figures) are forced into the lead under any required pressure, so as to
consolidate it into an impermeable substance, in which the projecting ribs of steel
are firmly bedded.
9. The chamber is provided with an inside cylinder (d Figs. 1 and 3). This may
be slightly coned or tapered for a suitable distance at its rear end, to fit a similar
slightly coned surface on the rear end of the exterior of the rocket. The lower or coned
portion of the exterior of the rocket may also be lead coated in order that it may
take a better and more even bearing on the cylindrical collar, and to prevent the
possibility of the projectile jamming, or sticking fast in its seat.
10. Fig. 3. shews the arrangement by which the rocket projectile is secured in its
seat. This consists of a strong solid bolt e, which passes through the centre of the
base of the chamber and terminates inside in a cylindrical ring of steel, which is
provided with an interrupted screw. This engages in a female screw in the base of
the outer case or cylinder of the rocket, which is prolonged below the base plug for
the purpose.
When this safety bolt is disengaged, the projectile is cleared for
firing.
11. The rocket composition (y. Fig. 3) is fired by the spark from an ordinary
firing tube or detonator fixed in a small cylindrical hole in the centre of the safety
locking bolt. The strong spark from the firing tube pierces a small silk bag of fine
grain powder fixed directly in front of it, in a central hole in the base plug of the
rocket. When the projectile has moved a suitable small distance the base of the
exterior cylinder of the rocket will clear the lower edge of two equal longitudinal
slots cut in the cylindrical support, or inner cylinder of the air chamber (see Fig. 7.
which shews the arrangement in side elevation) and the compressed air will pour in
behind the rocket from two sides at once. As the rocket projectile travels forward
it gradually gains the full benefit of the driving pressure of the compressed air
directly behind.
12. The construction of the air chamber is shewn in Fig. 1. The longitudinal
strain upon it, due to the air pressure, is largely reduced, as compared with the
radial or bursting strain by the space taken up by the rocket, and by the steel
collar or inner cylinder which surrounds the rocket. Also the latter acts as a
strong central support to the air chamber, and takes part of the longitudinal strain.
The available section of this inner cylinder, after deducting the portion cut away
by the two longitudinal slots or air channels shewn in Fig. 7, is so proportioned as
compared with the thickness of the exterior cylinder of the air chamber, that a
suitable proportion, say one half, of the steel of the latter on the inside is sufficient
for the required longitudinal strength. Then the remainder, or outer half, may be

page_text: devoted to a wire-wound jacket of ribbon steel, which gives the strongest construc-
tion for resisting the bursting pressure of the compressed air.
13. An incombustible non-conducting lining to the rocket case, preferably of
compressed asbestos, is shewn at i Fig. 3. This is introduced between the rocket
and its steel case, and between the base of the shell and the head of the rocket.
It tends to prevent or retard the heating up of the metal case of the rocket by the
burning of the composition.
し
14. A side elevation of the breech of the gun is given in Fig. 8, shewing the
combined bolt withdrawing and firing lever k, of which details are given in Figs. 9
and 10. Referring to these figures it will be seen that the firing lever & has a
heavy ball at the handle and can be rotated by hand freely and rapidly, until the
fixed stops 1, come in contact with the corresponding stops m, m, which are flanges.
on the outer end of the safety locking bolt. Then the momentum of the weighted
handle of the lever is available to overcome the initial resistance to rotation of the
threads of the interrupted screw on its inner surface engaged with the rocket case,
and a further turn of th or 4th of the circle will disengage it.
thereupon a strong circular coiled spring of ribbon steel (seen in section at n, n
Immediately
Fig. 3) comes into play. It will press the whole bolt and its attachments back
with a sudden start. This will be a signal to the gunner that the rocket is actually
disengaged, and he can thereupon cock the percussion lock for firing. This lock
slides into grooves on the firing lever, or is otherwise readily attached to or
removable from it. During practice it can remain a fixture on the lever and
revolve with it.
15. A special construction of the interrupted screw of the safety locking bolt is
shewn in Fig. 11. The interrupted threads do not run right round the bolt with
the usual intervals. A small solid portion of steel remains on the left side of each
segment, supposing the screw to move from left to right in locking. When the
bolt is disengaged this continuous surface of steel on the left face of each moving
segment will then come in contact with the right hand side of each fixed segment.
Hence the overriding of the segments or burring up of their edges under a powerful
stroke of the turning lever will be avoided. In construction the portion of the
screw to be thus left solid may be slotted away, if desired, together with the
adjoining interval, and a longitudinal piece of steel fixed in its place in an undercut
groove as shewn on the section.
16. The firing lever k is suspended as shewn on Fig. 8. from a small rotating
traveller or hoist o, above the breech of the gun. Before the chamber is put in
position, the traveller can be turned round sideways through 180°, or any lesser
angle, to a forward position out of the way.
After the chamber is locked on it
can be swung round to its front position as shewn on the drawing. When not
required for action it can be easily and quickly dismantled and stowel away.
This traveller suspends the weight of the firing lever, and retains it in its right
place exactly opposite the centre of the gun.
the traveller is a little to the right or left of the centre of the gun, that it may not
The centre or supporting pivot of
prevent an uninterrupted view along the centre line.
17. The rear end of the exterior of the gun itself is prolonged below to form a
projecting bracket or shelf (see Fig. 8.) on which the chamber rests, as far back as
point behind its centre of gravity. Hence the weight of the chamber is taken by
he bracket, and the jamming of the threads of the interrupted screw by the
reight of the chamber hanging upon them is prevented.
Having now particularly described and ascertained the nature of my said inven-
ion and in what manner the same is to be performed, I declare that what I
laim is:-
1. The method or arrangement whereby the breech or breech chamber of the
un containing the projectile and its propulsive power is detachable from the gun,
nd can be fixed or removed as required substantially as shewn on the drawings.
2. The combination of a charge of compressed air to give initial propulsion to

page_text: the projectile with a powerful rocket to maintain that initial impetus during its
flight.
3. The method or arrangement or combination whereby the usual provision of
separate air pumps or compressors, or air storage reservoirs or cylinders
permanently attached to, or forming part of each individual gun, for the purpose of
liberating an assigned portion of compressed air for the pneumatic propulsion is
avoided. In this system all the air chambers for the same description of gun are
separate, similar, and interchangeable. Hence any required number of them, with
their projectiles, can be assigned to any one gun, or forthwith removed to any other
gun, just as is done with the cartridges and shells of ordinary powder guns.
cach projectile has attached to it, independently of the gun, its own proper charge
of compressed air and no more.
And
4. The method of dispensing with fixed trunnions on the gun by causing it to
slide easily through a given portion of its length on a roller path, running within a
separate trunnion ring, substantially as shewn on the drawings and explained under
par. 4 above.
5. The combination whereby raised flanges, which serve to strengthen the gun
laterally, serve also for the bearings of the sliding roller path.
6. The method or arrangement whereby the gun is balanced at or near its centre
of gravity, with only such small preponderance as may be desired both with and
without its breech-chamber by aid of the sliding roller path and separate trunnion
ring, as explained under par. 5 and 6 above.
7. The method or arrangement whereby the traversing of the gun is provided
for by the revolution on a turntable of a separate trunnion ring through which the
gun slides as described.
8. The method or combination whereby the bearing or support of the breech
elevating gear slides backwards and forwards, while the gun itself slides corre-
spondingly backwards and forwards within its trunnion ring, as explained in
par. 6 above.
9. The combination whereby the projectile itself fills up the aperture or mouth,
and the entire central portion of the air chamber, and forms its own joints to retain
the compressed air, whereby all ordinary valves or moveable fittings to retain it are
avoided and this without any permanent forward driving pressure on the
projectile, substantially as shewn on the drawings.
10. The method or arrangement whereby the air-chamber for the compressed air
forms the breech of the gun itself, substantially as shewn.
11. The special construction of the air chamber, or combination consisting of an
outer and an inner cylinder, to retain the compressed air, with slots in the inner
cylinder for its exit, while the inner cylinder forms a strong central bolt to support
the chamber against the longitudinal strain due to the compressed air, substantially
as shewn on the drawings and explained above in par. 8.
12. The special construction of the air tight joints between the air chamber and
projectile to retain the compressed air, substantially as shewn on the drawings and
explained in par. 8 above.
13. The method or combination whereby the rear end of the projectile is slightly
coned and lead coated, substantially as explained in par. 9 above.
14. The method or combination whereby the projectile is secured in its seat by
a safety locking bolt passing through the centre of the base of the air chamber,
which bolt can be actuated from the outside to set the projectile free, substantially
as explained in par. 10. above.
15. The method or combination whereby the rocket composition is fired by the
spark from an ordinary firing tube or detonator fixed in a suitable cylindrical hole
in the centre of the safety locking bolt, substantially as explained in par. 11 above.
16. The method or combination whereby the projectile, after moving a given
distance from its seat, gradually gains the driving pressure of the compressed air
pouring in behind it through the longitudinal slots in the inner cylinder of the air
chamber, substantially as explained in par. 11 above.

page_text: 17. The method or arrangement of inserting an imcombustible non-conducting
lining inside the rocket case to retard its heating up by the burning away of the
composition as explained in par. 13 above.
18. The special construction of the firing lever, whereby the acquired momentum
of a heavy ball or weighted handle is made available to overcome the initial
resistance to turning of the interrupted screw of the safety locking bolt, sub-
stantially as explained in par. 14 above.
19. The combination whereby the lever which actuates the safety locking bolt
for its release is also the firing lever which carries the lock or firing apparatus,
substantially as explained in par. 14 above.
20. The method or combination whereby the release of the safety locking bolt is
indicated to the eye of the gunner who works the gun, by the release of a circular
coiled spring, substantially as explained in par. 14 above.
21. The special construction of the interrupted screw of the safety locking bolt,
whereby a small solid portion of steel is fixed on the inside of each moving segment,
substantially as described in par. 16 above.
22. The combination whereby the firing lever is suspended from a rotating
traveller or boist above, which carries its weight, and holds it in position for its
work, substantially as explained in par. 16 above.
23. The method of prolonging the rear end of the gun on the under side to form
a projecting bracket or shelf on which the chamber rests to a point behind its
centre of gravity, so as to prevent the jamming of the threads of the interrupted
screw by the weight and backward leverage of the chamber as explained in
par. 17. above.
Dated this 26th day of April 1893.
HENRY ELSDALE,
Lieut.-Colonel, R.E.