IMPROVED APPARATUS FOR POINTING ORDNANCE, AND RESTORING THE AIM OF THE PIECE, EITHER BY DAY OR NIGHT, WHEN IT IS ONCE OBTAINED
Year: 1855

page_text: LETTERS PATENT to David Davidson, of Meiklewood by Stirling, North
Britain, Captain in the Honorable East India Company's Service, for the
Invention of "IMPROVED APPARATUS FOR POINTING ORDNANCE, AND RESTORING
THE AIM OF THE PIECE, EITHER BY DAY OR NIGHT, WHEN IT IS ONCE OBTAINED."
Sealed the 6th July 1855, and dated the 17th January 1855.
PROVISIONAL SPECIFICATION left by the said David Davidson at the
Office of the Commissioners of Patents, with his Petition, on the 17th
January 1855.
I, DAVID DAVIDSON, of Meiklewood by Stirling, North Britain, Captain in
the Honorable East India Company's Service, do hereby declare the nature
of the said Invention for "IMPROVED APPARATUS FOR POINTING ORDNANCE, AND
RESTORING THE AIM OF THE PIECE, EITHER BY DAY OR NIGHT, WHEN IT IS ONCE
OBTAINED," to be as follows:-
Considerable inconvenience and difficulty arise in pointing ordnance with
any accuracy or certainty, except when the object aimed at or to be struck is
distinctly visible from the gun or other piece of ordnance; and as from the
recoil of the piece after every discharge the position thereof is changed, and
consequently requires replacing in its original position before being fired again,
it is of the greatest importance, in order to ensure accuracy in firing, that
the piece should be restored as near as possible to its original position. It is

page_text: scarcely necessary to point out the difficulty of so doing at night, or when the
piece is surrounded with dense smoke, which will effectually obscure the object
to be hit. The object of the present Invention is to facilitate the bringing the
piece to its original position, so that when once the range and correct aim of
the gun has been ascertained with certainty, the correct aim may always be
restored after every discharge, no matter how the position of the piece may
have been disturbed or altered by the recoil.
.
This object is effected by means of a simple apparatus, to be used in con-
junction with a telescope applied to the piece by means of s, or other
equivalent contrivances, whereby the axis of the telescope may always be made
to maintain a constant relative position to the axis of the piece. For
convenience I do not propose to attach the telescope to the piece, but merely
adapt thereto Y, supports, or studs, in or against which the telescope may
be laid or made to rest while an observation is being taken. Detached from
the piece, and placed in any convenient position in relation thereto, I place a
collimeter, constructed on the same principle as those used for astronomical
purposes. This collimeter must be so placed that the observer, when the
télescope is placed in its or supports on the gun, may, by a simple
adjustment of the apparatus, look through the telescope and down the tube
of the collimeter..
"
The apparatus is used in the following manner :-The collimeter having
been placed in a convenient position, the gun must be laid on the object to be
struck, and when the aim has been correctly ascertained, by firing a few
experimental shots at the object, the telescope must be placed in its y' or
supports on the piece, and the axis of the tube of the collimeter, brought
accurately into coincidence with the axis of the telescope; the collimeter
must then be clamped in this position, and when the position of the gun has
been shifted by firing, and the aim consequently lost, it may be restored by
bringing the axis of the telescope into coincidence with the axis of the tube
of the collimeter.
The collimeter, and also the telescope, are provided with cross wires, and
the rear end of the collimeter is illuminated by means of a lamp and reflector,
so that the cross wires of the collimeter may be seen through the object lens
of the instrument, and be highly.magnified thereby.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said David Davidson in the Great Seal Patent Office on the
17th July 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
DAVIDSON, of Meiklewood by Stirling, North Britain, Major in the Honorable
East India Company's Service, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of January, in the year of our
Lord One thousand eight hundred and fifty-five, in the eighteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said David Davidson, Her special license that I, the said David
Davidson, my executors, administrators, and assigns, or such others as I,
the said David Davidson, 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 "IMPROVED
APPARATUS FOR POINTING ORDNANCE, AND RESTORING THE AIM OF THE PIECE, EITHER
BY DAY OR NIGHT, WHEN IT IS ONCE OBTAINED," upon the condition (amongst
others) that I, the said David Davidson, by an instrument in. writing under
my hand and seal, 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.
NOW KNOW YE, that I, the said David Davidson, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, and to the
letters and figures marked thereon (that is to say):-
:-
Considerable inconvenience and difficulty arises in pointing ordnance with
any accuracy or certainty, except when the object aimed at or to be struck is
distinctly visible from the gun or other piece of ordnance; and as from the
recoil of the piece after every discharge the position thereof is changed, and
consequently requires replacing in its original position before being fired again,
it is of the greatest importance, in order to ensure accuracy in firing, that the
picce should be restored as near as possible to its original position. It is
scarcely necessary to point out the difficulty of so doing, or of obtaining any-
thing near a correct aim at night, or when the piece is surrounded with

page_text: dense smoke, which will effectually obscure the object to be hit. The object
of the present Invention is to facilitate the bringing the piece to its original
position, or as nearly so as may be necessary for all practical purposes, so that
when once the range and correct aim of the gun has been ascertained with
certainty, the gun may always be properly pointed after every discharge, no
matter how the position of the piece may have been disturbed or altered by
the recoil occasioned by the previous discharge.
This object is effected by means of a simple apparatus, to be used in con-
junction with a telescope applied to the piece by means of Y", or other
equivalent contrivances, whereby the axis of the telescope may always be made
to maintain a constant relative position to the axis of the piece. For conve-
nience I do not propose to attach the telescope to the piece, but merely adapt
thereto Y, supports, or studs, on or against which the telescope may be laid or
made to rest while an observation is being taken. Detached from the piece,
and placed in any convenient position in relation thereto, I place an instrument
or apparatus, which I denominate the collimator, as it is constructed on the
same principle as collimators used for astronomical purposes. This collimator
must be so placed that the observer (when the telescope is placed in its Y* or
supports on the gun) may, by a simple adjustment of the apparatus look through
the telescope, and down the tube of the collimator.
In order, however, that my Invention may be clearly understood, I have
shewn in the accompanying Drawings various views of my improved apparatus,
as adapted to a battering gun.
Fig. 1 is a side view of a gun in position in a battery, and with my improve-
ments adapted thereto. A is the gun or piece of ordnance; B, the telescope
adapted thereto; and C, the collimator placed on a stand behind the gun.
Fig. 2 is a side view of the telescope I intend to employ for the purposes. of my
Invention. It is furnished at each end with a collar a of gun metal, and has in
its focus a cross, either drawn on glass or made of wires, as is usual in levelling
telescopes. On the piece of ordnance are fixed four brass knobs or screws,
having round heads. Fig. 3 represents a plan of part of a piece of ordnance,
in which four of these knobs b, b, are screwed. Fig. 4 is an end view of the
gun, shewing the knobs with the telescope in position thercon, as when an
observation is being made. These knobs are screwed into the gun, a little on
one side of the ordinary sight, and in front of the touch-hole. It will be seen
in Figures 1 and 4, that the knobs b, b, form supports for the telescope to rest
on, and they may be fixed either parallel to the axis of the gun or at an angle,
so as best to suit the most firm and convenient position in which to place the
collimator, either behind or in front of the gun within the battery. In place

page_text: of employing a collimator, such as that herein-after described, the cross in the
telescope might be brought to bear on two crosses or points, placed one behind
the other at any convenient spot, which, when brought into allignment with the
cross in the telescope, will shew that the piece of ordnance has been brought
into its normal position. I, however, prefer to use the collimator, as the other
arrangement would require the gun to be brought back into the identical
position it originally occupied, which is difficult if not impossible in practice;
whereas, when the collimator is used, it will only be necessary to catch sight
from the telescope of one of the parallel rays proceeding from the collimator
tube; and when this is done, it will demonstrate that the piece has been
brought in a line parallel to and within an inch or so of its original position.
Fig. 5 is a longitudinal section of the collimator; and Fig. 6 is a cross section
thereof, which consists of a square. or other shaped wooden or metal tube c,
having a lens fixed therein, and is mounted in an external case in order to
admit of adjustment, as will be hereafter explained. The collimator tube c is
provided internally with a cross similar to that in the telescope B on the gun.
This cross is placed in the focus of the lens of the collimator, and is illuminated
by a lantern or lamp fat the other end. The collimator tube, as before
mentioned, is fixed within a box d, d, as shewn in Figures 5 and 6, and by means
of two clevating screws e, e, it is capable of motion in the vertical plane, either
parallel or in angular elevation. This collimator, if the telescope is laid
obliquely on the gun, may be placed on the ground; but it is thought better,
for reasons hereafter mentioned, to place the telescope parallel or nearly so to
the axis of the gun, in which case the collimator is raised upon a stand, which
may be formed by four posts driven into the ground clear of the recoil of the
gun, as shewn in Figures 1, 5, and 6. On the top of the posts is fixed a square
frame of wood g, having two slot holes h in two of its opposite sides, as shewn
in Fig. 5; through these slot holes pass two screws i, i, which enter the bottom
of the collimator box, and admit of the box being clamped to the frame, and
thereby secured in any position. As these slot holes are wider than the screws,
the collimator can be moved not only to either side on the horizontal plane,
but also angularly in that plane. Thus the collimator has motion in every
required direction.
The apparatus is used in the following manner :-The gun is first laid by
its usual sights on the object to be struck, and the correctness of the aim having
been ascertained by firing a few experimental shots, the telescope is held
against the knobs 6 by the hand while the gunner looks through it at the
collimator, which is then moved until the cross in its focus intersects with that
in the telescope. The telescope is then removed, and the collimator having

page_text: been clamped in the position so found, remains a fixture while the firing con-
tinues. The gun may then be fired, reloaded, and run up into the embrasure,
and is afterwards pointed or laid on the object, not by looking along the
ordinary sights, but by applying the telescope to the knobs on the gun as
before, and by moving the gun with the usual appliances until the cross of the
telescope B intersects that of the collimator C; and when this is done, the gun
must have been brought into the position in which it stood before the first shot
was fired, or else in one exactly parallel to it in every respect; and I need
hardly say,
that if the axis of the gun be placed parallel to and within an inch
or two of its original position, the effect as regards accuracy of aim is for all
practical purposes the same as if it were in the identical position in which it
was first laid; for the amount of error in the striking of the shot due to this
cause will be merely the distance by which the gun has been moved out of
its first position, and can never exceed an inch or two.
The object glass of the collimator being from four to five inches in diameter,
a column of parallel rays of this diameter will issue from it, and be met by a
similar column, though of less diameter, issuing from the telescope; and as
each of these rays gives the image of the cross in the instrument from which
it issues, the requisite intersection can be made by the coincidence of any of
the rays of the telescope and collimator, so that it is unnecessary to bring the
axis of the two instruments into exact coincidence. This allows of considerable
latitude as to the position of the gun, and renders unnecessary any more
delicate adjustment than is now requisite in laying guns by the ordinary sights;
and this constitutes one of the chief advantages arising from the use of the
collimator.
Moreover, the two crosses being greatly magnified and in the same plane of
vision, their intersection can be effected more readily and with much more
accuracy than the allignment of the ordinary sights of the gun with the object
aimed at, the three points to be brought into coincidence being in the latter
case at different distances from the eye, so that only one of the three can be
seen at the same moment with distinctness. A further advantage to be derived
from the use of the telescope is, that it remedies defective sight in the gunner,
and enables a short-sighted man to lay a gun with as much accuracy, as another
whose vision is perfect.
As already stated, the telescope may be laid obliquely on the gun and the
collimator placed upon the ground, but this would be suitable only for short
ranges; .as at short ranges it is not usual to make any correction on account
of the gun losing its horizontal position, from the platform, giving way under
a heavy fire; but to render this apparatus available for long ranges it is
こ 13

page_text: necessary so to adjust the knobs that the axis of the telescope would be
parallel or nearly so to the axis of the piece; the collimator must therefore
for this purpose necessarily be raised on a stand immediately behind the
platform, as shewn in Fig. 1.
In order to make use of the telescope for pointing the cannon for day
practice, in place of the ordinary sights, it has only to be reversed upon the Y"
b, b, so that the intersection of the cross may be made to bear upon the
object to be struck; and in this case the telescope should be provided with
marks h, k, Fig. 7, below the intersection of the cross, or with other similar
arrangement giving the degrees of elevation, any one of which, according to
the distance, would be brought to bear upon the object to be hit.
Having now described ny Invention of "Improved Apparatus for Pointing
Ordnance, and Restoring the Aim of the Piece, either by Day or Night, when
it is once Obtained," and the means of carrying my Invention into effect, I
would observe in conclusion, that although I have stated that I
propose
a telescope in conjunction with the collimator, yet considerable advantage may
be derived, even if only plain sights are employed. I, however, greatly prefer
to use the telescope, as greater accuracy can be obtained thereby; but I do
not intend to confine myself to the use of a telescope in conjunction with the
collimator; but I claim as new in the above described Invention the appli-
cation to guns or pieces of ordnance, for the purpose herein set forth, of either
a telescope or plain sight, provided with cross wires, so that by means thereof,
in conjunction with a collimator or other analogous contrivance, the piece of
ordnance may be brought into its proper position after every discharge, without
the necessity of observing the object to be struck. I also claim the use of the
collimator for facilitating this operation.
In witness whereof, I, the said David Davidson, have hereunto set my
hand and seal, the Eleventh day of July, in the year of our Lord
One thousand eight hundred and fifty-five.
FR. MIDDLEMAS, Witness,
J. P. for Haddingtonshire.
D. DAVIDSON. (L.S.)