IMPROVEMENTS IN TELESCOPIC SIGHTS FOR ORDNANCE OR FIREARMS
Year: 1881

page_text: LETTERS PATENT to Lothian Kerr Scott, Captain in Her Majesty's Royal
Engineers, of the Junior United Service Club, Charles Street, Saint James,
London, in the County of Middlesex, for an Invention of "IMPROVEMENTS IN
TELESCOPIC SIGHTS FOR ORDNANCE OR FIREARMS."
PROVISIONAL SPECIFICATION left by the said Lothian Kerr Scott at the
Office of the Commissioners of Patents on the 18th November 1881.
LOTHIAN KERR SCOTT, Captain in Her Majesty's Royal Engineers, of the Junior
United Service Club, Charles Street, Saint James, London, in the County of
Middlesex. "IMPROVEMENTS IN TELESCOPIC SIGHTS FOR ORDNANCE OR
FIREARMS."
In the telescopic sights patented by me, No. 31, A.D. 1877, "deflection" is given
by moving an arm in connection with the telescope laterally along a graduated
horizontal arc which reads to degrees and minutes. As long as the axis of the
telescope remains parallel to the arm and to the horizontal arc a horizontal angle
of "deflection" can be given between the plan of the axis of the telescope and the
plan of the axis of the gun equivalent to the measurement registered by the
movement of the arm of the graduated horizontal arc. Thus if the movement
indicated 5° 10' the angle between the plan of the axis of the telescope and between
the axis of the gun would be actually 5° 10', but when the telescope is depressed
through a vertical angle to give the required angle of "elevation" the axis of the
telescope is no longer parallel to the arin and plane of horizontal are but at an
angle to it; hence the angle in this case between the plan of the axis of the
telescope and the plan of the axis of the gun would not be truly measured by the
number of degrees and minutes registered by the movement of the vernier along
the horizontal arc, but it would be less and would vary with every increased or
diminished depression of the telescope till it became again parallel to the arm.
This then is a great inconvenience for a scientific instrument, and to dispense with
this defect I have modified the arrangement for giving "deflection" shewn in my
Patent No. 31, A.D. 1877, which I will call No. 1 improvement.

page_text: No. 1 improvement consists in making both the horizontal are and arm to
revolve in a vertical plane in conjunction with the telescope when it is depressed
for giving angles of "elevation" instead of their remaining stationary as heretofore
under these circumstances. This arrangement will allow of the true angle of
"deflection" being read off by the indicated measurements on the horizontal arc.
A cross level must be rigidly and immoveably fixed to the telescopic sight at right
angles to the axis of the gun.
No. 2 improvement consists in giving "deflection" to the axis of the telescope
by converting the present fixed diaphragm which contains the "cross wires" into
a sliding diaphragm, and by registering its lateral movement by means of a
graduated scale fixed in the same vertical plane with the "cross wires" or by a
micrometer headed screw which moves the sliding diaphragm. A cross level
must be rigidly fixed to the telescopic sight at right angles to the axis of the gun.
No. 3 improvement consists in the arrangement of the already patented telescopic
sight, No. 31, A.D. 1877, necessary for carrying into practice an improved method
for "laying" a gun when behind a parapet for what is technically called "indirect
fire" (i.c.) when the object to be fired at cannot be seen when looking through the
sights of the gun.
The method consists in "laying" the gun at two marks in rear of the parapet
with the same telescopic sight, one mark placed in line with the axis of the gun to
the rear, the other mark in line or thereabouts with the horizontal axis of the
trunnions of the gun, which, in direction, is at right angles to the axis of the gun.
The mechanical arrangement required to effect.this" laying" is as follows:-
A second telescope is fitted at right angles to the telescope of the sight, the object
glass of the former being made to focus the mark in line with the axis of the
trunnions on to a prism or reflector placed inside the telescope immediately under
the "cross wires" of the telescopic sight. This mark, together with the mark placed
in the direction of the axis of the gun, will then be seen by the same eyepiece.
When both marks coincide on the vertical.wire of the telescopic sight the gun will
be correctly "laid." This method of "laying" could also be done by fixing a prism
on the axis of revolution of the telescopic sight.
A level will have to be attached to the telescope of the telescopic sight parallel
to its axis if it be intended to give the angle of elevation of the gun with the
horizon.
No. 4 improvement. To dispense with the graduated vertical are in the
telescopic sight, Patent No. 31, A.D. 1877. This improvement requires the
following mechanical arrangement :-
"
If the telescope is to be, attached to the backsight the graduated vertical arc
which registers the angle of "elevation can be dispensed with by obtaining the
required angle of elevation by depressing the telescope so that its "
directed on to the tip of the foresight.
cross wires
"
are
This foresight slides up and down, and is graduated similarly to the tangent
sight for "range" and "deflection."
Supposing that the maximum angle of elevation at which the gun is to be fired
be 12° the foresight should be graduated to 12°, and its tip will rest when down
in its socket on a level with the axis of revolution of the telescopic sight.
To give an angle of elevation of 3° the foresight would be raised 9° out of tho
socket and tho telescope depressed on to it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lothian Kerr Scott in the Great Seal Patent Office on the
18th May 1882.
LOTHIAN KERR SCOTT, Captain in Her Majesty's Royal Engineers, of the
Junior United Service Club, Charles Street, Saint James, London, in the County
of Middlesex. IMPROVEMENTS IN TELESCOPIC SIGHTS FOR ORDNANCE OR
FIREARMS."
66
n
My Invention, which I designate as "Improvements in Telescopic Sights for
Ordnance and Firearms," relates to:-1. Improvements in the inechanical con-
struction of the telescopic sights already patented by me, No. 31, A.D. 1877, so as
to render these sights more solid, less likely to get out of adjustment, and more
accurate. 2. Improvements in the mechanical method for giving "deflection
(described in Patent No. 31, A.D. 1877), and also in the method for giving angles
of "elevation." 3. Improvements in the bracket for holding the sight and in the
original method of levelling in Patent No. 31, A.D. 1877. 4. Improvements due
to the combination of a telescopic sight with the revolving sight already patented
by me, No. 1218, A.D. 1880. 5. Improvements in substituting lines cut on the
glass of the eye piece of the telescope for a diaphragm with "cross wires."
6. Improvements in the method of aiming to the rear when firing from behind a
parapet, which prevents the "line of sight" being taken direct on the object.
Telescopic sights with the said improvements may be applied to any ordnance.
The manner in which I carry the said Invention into practice is illustrated in
the accompanying Drawings in two Sheets. Fig. 1 (Sheet I) is the side elevation
of a telescopic sight shewing the vertical arc (a, a,) permanently fixed to the body
of the sight, (g,g,) so that (a, a,) has no horizontal movement, as was the case in
Patent (No. 31, A.D. 1877); the level (d) is permanently fixed at right angles to
the axis of revolution of the sight, which is parallel to the axis of the piece; the
vernier (v) is attached to a collar (c, c) fixed to the telescope (t), and (e), shewn
shaded, is the sliding diaphragm for giving " deflection;" Fig. 3 shews an enlarged
sketch of the sliding diaphragm (e), the scale (8, s,) for registering the amount of
"deflection," the nut (n) for moving the sliding diaphragm, and (h, k,) the fixed
diaphragm inside the telescope.
It is seen, therefore, that by this sliding diaphragm (e) a horizontal angle can be
given to the "cross wires" of the telescope; in the same manner, therefore, by
making the diaphragm to move vertically instead of horizontally a vertical angle
can be given to the "cross wires" of the diaphragm. Hence if considered advisable
the angle of "elevation" now given by the vertical depression of the telescope can
also be given by a sliding diaphragm inside the telescope and the actual movement
of the telescope dispensed with. Another method of giving horizontal and vertical
angles without moving the whole of the telescope is by making the eye piece or
the object glass to move horizontally and vertically, but by having the "cross wires"
on the eye piece or in a fixed diaphragm; Fig. 2, side elevation of a 60° telescopic
sight, similar to that described in Fig. 1, with the exception that the "deflection
is not given by means of a sliding diaphragm but by a lateral movement of the
telescope (t). In Patent No. 31, A.D. 1877, "deflection" is given by a lateral
movement of the telescope, but owing to the graduated horizontal are (K), along
which the vernier (v) travels, being stationary and not conforming to the vertical
movement of the telescope, it is impossible without calculation to give by means
of the vernier (v) and graduated arc (k) the degrees and minutes corresponding to
any given angle of "deflection." For instance, if the telescope had been given an
angle of "elevation" of 10°, and it were required to give 1° 30′ "deflection," a

page_text: norizontal novement to the amount of 130 on the horizontal arc (K) would not
give the telescope an angle of 1° 30′.
Hence to obviate this defect, in Fig. 2 (Sheet I.) of Patent No. 5053, A.D.
18th Nov., 1881, (h, k) (representing the horizontal arc in Patent No. 31,
A.D. 1877) is made to revolve in a vertical direction, together with the telescope,
between two cheeks. The telescope pivotting between the two trunnions receives a
lateral movement by turning the micrometer headed screw (m), Fig. 4, and the
degrees are read off the limb (k, k,) by tho vernier (v); which is attached to the
telescope by a collar. Fig. 4 is the front elevation of Fig. 2, and shows the
vernier (v), the graduated arc (h, k) and the screw (m) for giving "deflection."
When the telescope is depressed (k, k,) moves up with it. I have omitted in
the Drawings those parts which remain the same as shewn in Patent No. 31,
A.D. '77.
In order to dispense with "cross wires," which are likely to be broken, I
substitute lines cut on the eye piece, or use a metal point placed horizontally or
vertically in a diaphragm. Fig. 5 shows how the levelling arrangement of the
sight and bracket, shown in Patent No. 31, A.D. 1877, may be simplified. The
body (g, g) of the instrument is made so that all the parts of the sight will be on
one side of the axis of revolution. The sight in this form when placed into the
grooves of the bracket would overbalance, were it not kept from so doing by its
projection, which comes against the levelling screw (p) working in, and forining
part of the bracket attached to the gun. The weight of the sight then acts in the
same manner as and takes the place of the spring of the original bracket shewn in
No. 31, A.D. 1877. It will be noticed that in this arrangement the lovelling screw is
transferred from the sight to the bracket. Fig. 6 shews how by turning the sight
upside down the same bracket may be used for aiming to the rear. Fig. 7 shows
method for preventing the screws from being unscrewed by rough transport. This
is very important. The screw is screwed home upon the washer, which has a thin
edge of metal left for "burnishing" or folding over the head of the screw.
Fig. 8 shews a telescopo with, reflectors in it for aiming to the rear. It consists
of one piece, two object glasses, and mirrors so adjusted in the interior of the tube
common to both object glasses that an observer can see an object to the right and
left of himself at the same time with the one eye piece. Such a telescope could be
employed advantageously for indirect fire behind parapets, if it were substituted
for the telescope in the telescopic sight. To use this reflecting telescope place one
scale with white numbered divisions on the parapet in front of the gun, and a second
scale similarly graduated with red divisions to the rear. The reflecting telescope
being on the gun is interposed between the two scales. Suppose a shot to have
been fired when the white third division and the red third division wero seon
covering each other in the eye piece, and it be required to repeat the aim, it is only
necessary to shift the gun till any two like divisions on the two scales cover in the
eye piece.
The several Drawings in Sheet II. shew the combination of a telescopic sight
with the revolving sight already patented by me, No. 1218, A.D. 1880, and are so
explicit that it needs very little explanation, excepting to state the special
peculiarities of the telescopic sight. The telescope revolves vertically about hollow
trunnions at (d). The nut for giving "deflection" by means of the sliding
diaphragm and scale (already explained in this Specification works in the hollow
trunnions, and is well protected. The telescope is clamped at any angle required
by clamping the square collar (f. f) (which holds the object glass end of the
telescope) by the two nuts (b, b). The vernier is attached to the telescope, and
travels in a graduated slot in the vertical arc. The peculiarity of this instrument
consists in having the free end of the telescope loosely encased in a collar (f.f.) from
which project the screw pins on which the clamping screws (b, b,) work. The
square collar by its movement moves the telescope with it. The telescope is kept
hard up against the top of (f, f.) by means of a spiral spring coiled round the screw
attached to (f) around which the micrometer nut (m) turns. The object of the

page_text: independent movement of the telescope in the square collar (f.f.) is to enable
minutes of are to be given to the telescope by a micrometer head shewing large
divisions, whether they be in yards of range or minutes of arc.
Having thus fully described my said Invention, and the manner of performing
the same, I wish it to be clearly understood that I claim,-
1. The method of giving and of measuring "deflection" by means of a sliding
diaphragm, and fixed scale attached to a fixed diaphragm.
2. The method of giving "deflection" by a lateral movement of the telescope
along a graduated arc, which moves in conjunction with the telescope along the
vertical are when the telescope is depressed for giving angles of "elevation."
3. The method generally of giving horizontal and vertical angles (ie., " deflection"
and angles of "elevation" in artillery terms) in telescopic sights by means of,-
(a) A sliding diaphragm with cross wires sliding horizontally and vertically
in n fixed diaphragm in the telescope, the value of the angles being registered by a
scale attached to the fixed diaphragın; or,-
(b) By giving the eye piece or the object glass of the telescope a similar
horizontal and vertical movement.
"
4. The method of dispensing with the diaphragin and "
cross wires of the
telescope, by substituting in their place lines cut on the glass of the eye piece of
the telescope.
5. The method employed for preventing the screws from becoming uninten-
tionally unscrewed.
6. The method of levelling the telescopic sight by means of a screw in the
bracket, and by utilizing the eccentricity or absence of balance of the sight as &
spring to give the sight the required movement when when the levelling screw of
the bracket is turned.
7. The method of aiming to the rear by reversing and turning the sight upsido
down in the grooves of the bracket.
8. The method of aiming to the front and rear, by means of a reflecting telescope
being substituted for the telescope of the sight and by employing scales.
9. The method of dispensing with horizontal and vertical arcs for the telescopic
sight by borrowing the "clevation" and "deflection" from the service sights, as
explained in the Provisional Specification.
In witness whereof, I, the said Lothian Kerr Scott, have hereunto set my
hand and seal, this Eighteenth day of May, in the year of our Lord
Eighteen eight hundred and eighty two.
L. K. SCOTT CART RF 101