OYDRIVNAL MUITIVATION.
Year: 1897

page_text: BOYDRIVNAL DI MUITIVATION.
An Improved Range Finder.
I, JOHN JERVIS GARRARD, of Eshowe, Zululand, South Africa, Civil Engineer, do
hereby declare the nature of this invention to be as follows:-
My invention consists essentially of an instrument which may be attached tem-
porarily or permanently to, or slipped on to, the barrel, foresight, or any other portion
of any rifle, or any other article whatsoever, in such a manner that by placing the eye
at a certain distance from it and looking through the instrument it is possible to
ascertain the distance of any object of known dimensions from the instrument. The
instrument consists of a small light frame of metal or other suitable material attached
at its base by a hinge or pivot to either a short length of tubing fitting the barrel of
a rifle or other similar article so that it stands vertically above the foresight thereof,.
or to a spring clip similarly placed, or to the base of the foresight itself or to any
other suitable part of the rifle or other article to which it is applied. The frame when
not in use may be foided down in a similar manner to the back sight of a rifle to which
it is somewhat similar in form. The frame is so constructed that a number of very
thin wires, threads, hairs or the like or a transparent diaphragm with lines marked
upon it may be inserted into and stretched across its hollow central portion either
vertically or horizontally. This may be effected by constructing the upper part of
the frame in two halves so that the wires threads hairs or the like may be adjusted in
their proper positions and fixed in the usual manner adopted in other instruments
where wires threads hairs or the like are employed, if a diaphragm is used this is
likewise inserted between the two halves of the frame which is provided with screws
to screw the two halves together again when the adjustment of the wires threads hairs or
the like or the diaphragın is complete. The principle involved in this instrument is that
of the stadia, wires threads hairs or the like or a diaphragm being used to subtend the
angle made at the observer's eye between two imaginary lines supposed to connect the
said eye with the vertical or lateral extremities of the object whose distance it is
required to ascertain. The distance at which the eye is held from the instrument,
which may be fixed by a mark on the stock (in the case of a rifle) or other convenient
position or by means of a folding eyepiece, taken in connection with the distance apart
of the wires, threads, hairs or the like, or of the marks on the diaphragm. And the
dimensions of the object observed, forms the basis upon which the distance of the
object from the instrument is calculated. One or more scales may be attached to the
instrument to indicate the various distances corresponding to each wire or other mark
for objects of known dimensions; for example one scale to be used when observing men
on foot, another when observing men on horseback, another when observing any
particular kind of beast or big game. Or more than one frame may be attached to
the same base each having wires threads hairs or diaphragm adjusted to suit any
particular requirements the one being placed upright while the other or others remain
folded down. If the instrument be permanently hinged to the base of the foresight,
when folded down it may be protected by a very slight modification in the construction
of the ordinary sight-protectors. The usual position of the instrument when in use

page_text: is vertically above the foresight, so that however the line of sighting is never obstructed
& the weapon can be fired off without removing the instrument.
In using the instrument the observer places his eye vertically above a mark, or
against an eye piece, fixed on the rifle or other article to which the instrument is
attached. In the case of a rifle this mark may consist of a white spot conveniently
placed on the upper side of the stock at or near the place where the eye would be
held in the ordinary firing position. He then points the rifle or other article in the
direction of the object whose distance it is required to ascertain and looking through
the instrument directs the rifle or other article so that the bottom wire thread hair
or the like or bottom line on diaphragm, of the instrument, cuts the lowest point of
the object observed. The highest point of the object will then (if the range is com-
patible with the adjustment of the instrument) be seen to reach to one or other of
the upper wires threads hairs or lines or thereabouts. And as each wire thread hair
or line has a definite distance assigned to it for any one fixed height of object ob-
served, the distance of that object is at once determined. In some cases it may be
advisable to have wires placed vertically instead of horizontally or both, so that the
known length or breadth of an object may be observed instead of or as well as, its
height. This may be advisable in the case of observing quadruped animals and big
game whose bodies are longer than they are high.
This instrument is intended amongst other things to enable any person whether
skilled or not (1) to judge at a glance whilst actually covering the object aimed at
and whilst in ordinary firing position, the distance or range of the object at or near
which he desires to fire (2) to sight his weapon accordingly (3) to notice whether the
object is advancing or receding (4) to estimate the rate of advance or retreat (5) to
sight his weapon to a certain range & then to cover the object aimed at until it
reaches that range. And also to enable each individual soldier or other person to
ascertain at a glance independently for himself the range for which his weapon should
be sighted.
The instrument is applicable to any form of rifle firearm machine gun cannon &
the like whilst it may also be used on any article as simple as an ordinary stick, and
it is approximately accurate for estimating distances up to if not exceeding one mile
from the observer and very accurate for ranges up to half a mile.
Dated this Twenty-third day of November 1897 at Eshowe.
1, JOHN JERVIS GARRARD, of Eshowe, Zululand, South Africa, Civil Engineer, 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:-
My invention consists essentially of an instrument which may be attached
temporarily, or permanently to, or slipped on to, the barrel, foresight, or any other
portion of any rifle, or any other suitable kind of article whatsoever, in such a
manner that by placing the eye at a certain distance from it and looking through
the instrument it is possible to ascertain the distance of any object of known
dimensions from the instrument.

page_text: I will fully describe my invention with reference to the accompanying drawings in
which Fig. is a side elevation of my improved range finder attached to the
barrel of a rifle; Figs. 2 and 3 are elevations of same, showing two arrangements for
use under different circumstances hereinafter explained; Fig. 4 is a plan of Fig. 1,
and Fig. 5 is a diagrammatic view illustrating the principle upon which my improved
range finder is based.
The instrument consists of a small light frame F of steel, brass, or other suitable
metal or material, attached at its base by a hinge or pivot f to either a short length
of tubing, such as illustrated at T, fitting the barrel B of a rifle or other similar
article so that the instrument stands vertically above the foresight S thereof, or to a
spring clip similarly placed, or to the base of the foresight itself, or to any other
suitable part of the rifle or other article to which it is applied. The frame F when
not in use may be folded down as shown by dotted lines in Fig. 1 in a similar
Inanner to the back sight of a rifle to which it is somewhat similar in form. The
frame F is so constructed that a number of very thin wires, threads, hairs or the like,
such as shown at w, w, or a transparent diaphragm with equivalent lines marked
upon it, may be inserted into and stretched across its hollow central portion either
horizontally as in Fig. 2 or vertically as in Fig. 3. This may be effected by
constructing the upper part of the frame F in two halves F1 F2 so that the wires,
threads, hairs, or the like w w may be adjusted in their proper positions and fixed in
the usual manner adopted in other instruments where wires, threads, hairs or the
like are employed. If a diaphragm is used this is likewise inserted between the two
halves of the frame which is provided with screws ss to screw the two halves together
again when the adjustment of the wires, threads, hairs or the like, or the diaphragm
is complete. The principle involved in this instrument is that the stadia, wires,
threads, hairs, or the like, or a diaphragm being used to subtend the angle made at
the observer's eye between two imaginary lines supposed to connect the said eye with
the vertical or lateral extremities of the object whose distance it is required to
ascertain. Referring to Fig. 5, the distance y at which the eye of the observer is
held from the instrument, which may be fixed by a mark on the stock (in the case
of a rifle at approximately a point on the line o-o) or other convenient position or
by means of a folding eye-piece, taken in connection with the distance apart of the
wires, threads, hairs, ww or the like, or of the marks on the diaphragm, and the
dimensions of the object observed, forms the basis upon which the distance 1 of
the object from the observer is calculated. One or more scales may be attached
to the instrument as shown in Figs. 2 and 3 to indicate the various distances
corresponding to each wire or other mark for objects of known dimensions; for
example, one scale to be used when observing men on foot, another when
observing men on horseback, another when observing any particular kind of beast
or big game. Or more than one frame may be attached to the same base each
having wire threads, hairs or diaphragm adjusted to suit any particular require-
ments, the one being placed upright while the other or others remain folded down.
If the instrument be permanently hinged to the base of the foresight, when
folded down it may be protected by a very slight modification in the construction
of the ordinary sight protectors. The usual position of the instrument when in
use is vertically above the foresight, but it is so arranged however that the line
of sighting is never obstructed and the weapon can be fired off without removing
the instrument as will be clearly understood from Figs. 2 and 3.
In using the instrument the observer places his eye vertically above a mark in the
line o-o, or against an eye-piece, fixed on the rifle or other article to which the
instrument is attached. In the case of a rifle this mark may consist of a white spot
conveniently placed on the upper side of the stock at or near the place where the
eye would be held in the ordinary firing position. He then points the rifle or other
article in the direction of the object whose distance it is required to ascertain, and
looking through the instrument directs the rifle or other article so that the bottom
wire, thread, hair or the like, or bottom line of diaphragm, of the instrument, cuts

page_text: the lowest point of the object observed. The highest point of the object will then
(if the range is compatible with the adjustment of the instrument) be seen to reach
to one or other of the upper wires, threads, hairs, or line, or thereabouts.
And as
each wire, thread, hair or line has a definite distance assigned to it for any one fixed
height of object observed, the distance of that object is at once determined. In
some cases it may be advisable to have wires placed vertically as in Fig. 3 instead of
borizontally as in Fig. 2, or both, so that the known length or breadth of an object
may be observed instead of or as well as its height. This may be advisable in the
case of observing quadruped animals and big game whose bodies are longer than they
are high.
The diagram, Fig. 5, and the following formula and table clearly show the principle
upon which the adjustment of the wires referred to and the graduation of the
instrument is based for known ranges.
1200
1600
.064
"
"
"
1600
2133
⚫0479
"
دو
وو
720
960
•1065
د,
"
وو
It will be obvious that the adjustment may readily be varied to suit any
requirements.
This instrument is intended amongst other things to enable any person whether
skilled or not (1) to judge at a glance whilst actually covering the object aimed at
and whilst in ordinary firing position, the distance or range of the object at or near
which he desires to fire (2) to sight his weapon accordingly (3) to notice whether the
object is advancing or receding (4) to estimate the rate of advance or retreat (5) to
sight, his weapon to a certain range and then to cover the object aimed at until it
reaches that range, and also to enable each individual, soldier, or other person to
ascertain at a glance independently for himself the range for which his weapon
should be sighted.
The instrument is applicable to any form of rifle, firearm, machine gun, cannon,
and the like, whilst it may also be used on any article as simple as an ordinary stick,
and it is approximately accurate for estimating distances up to if not exceeding one
mile from the observer and very accurate for ranges up to half a mile.

page_text: Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. A range finder constructed on the principle herein enunciated in which an
arrangement of spaced wires, threads, hairs or lines upon a transparent diaphragm
carefully adjusted and mounted in a graduated frame such as above specified
attached to the rifle or article, is used to subtend the angle made at the observer's
eye between two imaginary lines supposed to connect the said eye with the vertical
or lateral extremities of the object whose distance is required and by which it can
be ascertained in the manner set forth.
2. The improved range finder constructed and adapted for use substantially in the
manner herein described and illustrated in the drawings.
Dated this Tantu thin
1000
For the Applicant,
J. C. CHAPMAN,
Chartered Patent Agent, 70, Chancery Lane, London, W.C.