AN IMPROVED CONSTRUCTION OR ARRANGEMENT OF RANGE FINDER FOR MILITARY USES
Year: 1879

page_text: "
LETTERS PATENT to James Gustavus Hamilton Holmes, of Newton Abbot,
in the County of Devon, Lieutenant Colonel, Half Pay, 12th Royal Lancers;
for the Invention of "AN IMPROVED CONSTRUCTION OR ARRANGEMENT OF
RANGE FINDER FOR MILITARY USES." A communication from abroad by
Arthur L'Estrange Hamilton Holmes, Brigade Major, and Major Bengal Staff
Corps, Meerut, Bengal, India.
Sealed the 20th January 1880, and dated the 28th August 1879.
PROVISIONAL SPECIFICATION left by the said James Gustavus Hamilton
Holmes at the Office of the Commissioners of. Patents on the 28th August
1879.
"
JAMES GUSTAVUS HAMILTON HOLMES, of Newton Abbot, in the County of
Devon, Lieutenant Colonel; Half Pay, 12th Royal Lancers. AN IMPROVED CON-
STRUCTION OR ARRANGEMENT OF RANGE FINDER FOR MILITARY USES." A com-
munication from abroad by Arthur L'Estrange Hamilton Holmes, Brigade Major,
and Major Bengal Staff Corps, Meerut, Bengal, India.
The object of this Invention is the construction of an apparatus for rapidly
finding and indicațing distances or ranges, especially very long ranges, for military
purposes.
For this Invention a hollow metal cylinder'f, z, h, j, shown in Figures 1 and 2
of the annexed Drawings, bent twice at right angles at and k is employed: Across
the corner z is a mirror at 45° to the axis of the cylinder, and at k is a half silvered
mirror, also at 45° to the axis,. and the silvered part of the mirror & being below;
the plane of section, the unsilvered being above.
At the H end the cylinder unscrews for adjustment, and at h is a third mirror
which when the tube is screwed together at the central part S is exactly in the
plane of the two former, and also at an angle of 45° with the axis. At A, outside.
this mirror, is a metal ring to prevent hoop H (hereafter described) slipping off.
At g is an opening through which object at B is reflected to mirror at p.
The hoop referred to fits closely to the cylinder which turns in it, also is pushed,
forwards and backwards in it from end with a ring soldered on the outside to the
bend of the tube. It can either be pushed by hand or with a gcrew motion. It
__

page_text: has two projections y, y, fitting on corresponding openings to receive them in stand.
The cylinder is of sufficient length to allow of its being pushed forward to C, say
3 feet,' more or less, and for portability will be divided about the middle with a
screw, which screw can be inserted into the hoop and withdrawn when not in use.
To use the apparatus :-Suppose from any given point it is required to dislodge a
battery of artillery, batch of general, or field officers, or other objectionable
gathering, the distance of which is necessary for accurate long range shooting,―
1. At A, Figure 3, set up range finder on its stand and use it as an optical square,
send assistant with staff in the line A, B, at right angles to A, X. The observer
taking a sight at X with instrument, and (when B is placed approximately by
pacing "b" yards) reflecting staff at B on line A, X.
2. With a wire, tape, or other very accurate measure place B (already ouly
paced) at "b" yards, say 31. 1'. 10.38" yards, or 20. 30. 40 or - yards.
-----
3. The stand is then moved to B, and the observer (having first reversed instru-
ment, turning it right round) takes a sight at X, pushing on tube through hoop
until A is reflected into his eye (as on line B X at C) where place a staff. The
line A, C, will then be at Rt angles to B, X, and as A C X, and A. C B, are similar
triangles, ac ::c: x ax = c² = b² a² & x =
-
82
a
a.
The application of the range finder is based upon the following mathematical
principle.
As the length of b varies from 20 to 50 yds., as x varies from 400 to 4,000 yards
and the length of the range required will hardly exceed 2,500 yards, it is presumed
in practice the distance a may be under 3 feet, and consequently that it may be
found practicable to have the tube something less than three feet. It- also
appears practicable (owing to the distance A, X, for which the present military rifle
is applicable, being under 3,000 yards) that the base b, on which the length of a,,
and consequently of the tube, much depends, may be taken at under 40 yards, a
very carefully prepared steel tape, or other measure is accurately used to mark
off 6 at one measurement to 31.1. 10.38" (or the square root of 1,000) yards or
31 607 yards, which assimilates with a spiral scale hereafter described; and allows
the distance at once to be calculated.
E, Figure 1, is the eye piece; K, a half silvered mirror at 45°.
Z, silvered mirror at 45°; S, screw joint; H, hoop through which cylinder Z, H,
is pushed, and turns round at S; y, y, are projections resting in corresponding
chambers fitted to stand.
A, a ring soldered round tube outside close to mirror, which prevents cylinder
being pulled out backwards through hoop; p, central point of mirror where
reflection hits it; at g is an opening for reflection. When observations are being
made from A or B, p should be immediately over either.
.
Iu Figure 2 the mirror inclined to axis at an angle greater than 45° <q ƒ z =
45°. Now when tube is pushed forward at A until B is reflected at this
angle, the observer looking at X sees B; suppose distance found to be A f d
then tan. A FB and bd tan. A FB of course tan. A ƒ B is a constant
and can be measured to 100th of an inch.
b
The instrument to rest on a carefully made stand on which it pivots, and which
allows it to rest horizontal without vibration, and also to be pushed forward and.
drawn back either by hand or screw. motion.
If one reflector only be used the tube would be made as in Figure 4.
In this case the eye hole E which should be very small; Å, the mirror at 45°
to axis, which should be made like the horizon glass of a sextant; B, unsilvered,
C, silvered; x, y, vertical line on which the distant object and the image of the second
point are to be brought. The line E X being thus defined the mirror.can be adjusted
from time to time.
"
=
The graduated spiral scale z, g, to record at once for a base, b ✓1,000yds.
Explanation of Figure 5, representing portion of cylinder enlarged after having

page_text: Second, a longer base admitting the more rough and ready method of adjusting
the cylinder by the hand, so as to reflect the head of the staff A into observer's eye
at B. With a carefully prepared tape 30. yds., 1'.-10-38" can be measured as.
accurately as 20 yds. or 30 yds., that is to say, with as little error.
The spiral scale is graduated to give actual values of x for different lengths of a
as near each other as possible (on the assumption that b² = 1,000) to the shortest
distance admitted of by the working length of cylinder; but if the base actually used,
e., b. be other than 1,000 and the distance read off on the scale be (x), then
=x, the true distance.
,
(1,000)
&
-
N.B. This method of graduating the spiral scale is not in any way intended to
restrict the base to 1,000 but only to perform mechanically the operations
required for working out the equation x = - 6s being assumed = 1,000, so that
for any other base the only remaining operation required is really nothing but
multiplying the recorded distance by the square of the new base, and assigning the
proper decimal point which at once gives the true distance of the observed object.
a
The tape prepared for ✓1,000 could be marked off also for distances of 10 = 20,
and 30 yards, from which by a second measurement distances of 40 and 50 yards
could be measured, giving squares of 100-400-900-1,600, & 2,500 yards, all
easy numbers for the slide rule to multiply with.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Gustavus Hamilton Holmes in the Great Seal Patent Office
i
on the 28th February, 1880.
A com-
JAMES GUSTAVUS HAMILTON HOLMES, of Newton Abbot, in the County of
Devon, Lieutenant Colonel, Half Pay, 12th Royal Lancers. "AN IMPROVED CON-
STRUCTION OR ARRANGEMENT OF RANGE FINDER FOR MILITARY USES."
munication from abroad by Arthur L'Estrange Hamilton Holmes, Brigade Major,
and Major Bengal Staff Corps, Meerut, Bengal, India.
:
The object of this Invention is the construction of an apparatus for rapidly
finding and indicating distances or ranges, especially very long ranges, for military
purposes. For this Invention a hollow metal cylinder f, z, k, j, shown in Figure 1
of the annexed Drawings, bent twice at right angles at z and kis employed. Across
the corner z is a mirror at 45° to the axis of the cylinder, and at k is a half silvered
mirror, also at 45° to the axis, the silvered part of the mirror k being below the
plane of section, the unsilvered being above. At the end the cylinder unscrews
for adjustment, and at h is a third mirror, which, when the tube is screwed together
at the central part S is exactly in the plane of the two former, and also.at an
angle of 45° with the axis. At A, outside this mirror, is a metal ring to prevent
hoop H (bereafter described) slipping off. At g is an opening through which object
at B is reflected to mirror at p.
5.
The hoop referred to fits closely to the cylinder, which turns in it, also is pushed
forwards and backwards in it from end with a ring soldered on the outside to the
bend of the tube.
It can either be pushed by hand or with a screw motion. It has two projections y, Y,
fitting on corresponding openings to receive them in stand. The cylinder is of sufficient
length to allow of its being pushed forward to C, say 3 feet, more or less, and for port-
ability will be divided about the middle with a screw, which screw can be inserted
into the hoop, and withdrawn when not in use. To use the apparatus:-Suppose
from any given point it is required to dislodge a battery of artillery, batch of
general or field officers, or other objectionable gathering, the distance of which is
necessary for accurate long range shooting,-
At A, Figure 3, set up range finder, on its stand and use it as an optical square,
send assistant with staff in the line A, B, at right angles to A, X, the observer
taking a sight at X with instrument and (when B is placed approximately by
pacing "b" yards) reflecting staff at B, on line A, X.
With a wire tape, or other very accurate measure, place B (already only paced,
at b yards, say 31·1'. 10·38" yards or 20, 30, 40 or ----- yards.
The
The stand is then moved to B, and the observer having first reversed the
instrument turning it right round, takes a sight at X, pushing on tube through hoop
until A is reflected into his eye (as on line B, X, on C) where place a staff.
line A, C, will then be at right angles to B, X, and as at A, C, X, and A, C, B, are
triangles acc: xa x = c² = b² - a² and x.=
a
a.
The application of the
range finder is based upon the following mathematical principle:-As the length
of b varies from 20 to 50 yards as x varies from 400 to 4,000 yards, and the length
of range required will hardly exceed 2,500 yards it is presumed in practice the
distance "a may be under 3 feet, and consequently that it may be found prac-
ticable to have the tube something less than 3 feet. It also appears practicable
owing to the distance A, X, for which the present military rifle is applicable, being
under 3,000 yards that the base "b," on which the length of "a," and consequently
"

page_text: of the tube much depends may be taken at under 40 yards, a very carefully pre-
pared steel tape or other measure is accurately used to mark off b at one measure-
ment to 31-1. 10.38" (or the square root of 1,000) yards or 31.607 yards, which
assimilates with a spiral scale hereafter described, and allows the distance at once
to be calculated.
E, Figure 1, is the eye piece; K is a half silvered mirror at 45°; Z, silvered mirror
at 45°; S, screw joint; H, hoop through which cylinder Z, H, is pushed, and turns
round at S; y, y, are projections resting in corresponding chambers fitted to stand;
A, a ring soldered round tube outside, close to mirror, which prevents cylinder
being pulled out backwards through hoop; p, central point of mirror where reflection
hits it; at g is an opening for reflection. When observations are being made
from A or B, p should be immediately over either.
-
In Figure 2 the mirror inclined to axis at an angle greater than 45° < q, f, z,
45° d. Now when tube is pushed forward at A until B is reflected at this
angle, the observer looking at X sees B; suppose distance found to be A, f=d,
then = tan. [A, F, B, and b = d tan. A, F, B, of course tan. A, f, B, is a constant,
and can be measured to 100th of an inch
•
b
2.
The instrument to rest on a carefully made stand on which it pivots, and which
allows it to rest horizontal without vibration, and also to be pushed forward and
drawn back either by the hand or screw motion. If one reflector only be used
the tube would be made as in Figure 4.
In this case the eye hole E may be very small; for trial model the length of
base selected is 30 yards. A, the mirror at 45° to axes, which should be made like
the horizon glass of a sextant; B, unsilvered, C, silvered; x, y, vertical line on
which the distant object and the image of the second point are to be brought; the
line E, X, being thus defined the mirror can be adjusted froin time to time.
→
The graduated spiral scale *, g, to record x at once for a base, b✓1,000 yards.
Figure 5 represents portion of cylinder enlarged after having been pushed through
collar H a certain extent to show the plan proposed for utilizing a spiral scale
engraved on the cylinder z, g, and graduated to give a in yards for every length of a or
B, C, in Figure 3, as calculated for a base b✓1000 = or 31 yards 1' 10-38".
The mirror piece at the end of the cylinder may be made to pull out or to
screw in and out so as to be removable for repairs and adjustment when necessary.
Within the outer tube or collar H is an inner collar with a circular movement
only, to which it is restricted by a band of semi-circular section fitting into a cor:
responding groove cut in the inner surface of the outer collar. Then the cylinder z, g,
sliding through the inner collar is pushed on till the point p (the central of the end
mirror) reaches C, of Figure 3, reflecting A into observer's eye at B. N.B. The
cylinder being of course turned round to admit of A's image reaching the mirror
at p through the circular opening in end piece, being thence reflected into the
observer's eye at B, looking through the eye piece E, Figure 1. As soon as this
reflection is seen the inner collar is clamped to the cylinder by the clamp c, l, to
prevent any further forward or backward movement of the cylinder, which latter
is there turned round together with the inner collar till a division on the spiral
comes immediately opposite an arrow head engraved on the outer collar H, which
will represent the direct forward movement made by the cylinder from the initial
or starting point infinity or a of scale.
The object of the spiral instead of a straight scale is simply to enable sub-divisions
of the scale to be made as by. regulating the slope of the spiral, the length of the
scale can be indefinitely increased.
The inner collar projects beyond the outer at the clamp end to enable the clamp
to be attached, and stops short of the outer collar at the other end so as not to
block the view of the spiral scale through the V shaped opening cut in the outer
collar until the cylinder is clamped. It has a perfectly free forward or backward
movement through the inner collar.
:

page_text: Practical application of spiral scale rule for graduating it. N.B. Given
base b=1,000. .Now x = or The scale is to be engraved not to show
a
1000
a
for every advance of the cylinder, but the corresponding value of x from infinity
to 1,000 yards (supposing the working length of the cylinder to be 36in. or 1 yard).-
Thus if x = a yards
a = zero.
The numbers engraved on the scale will be the yards in the 2nd column of the
table with the gaps fitted in as close as the scale will admit of.
Should any other base than 1,000 be selected, say b, the true value of x for this
new base would be found by multiplying the value given by the spiral scale by b₁
for, of course, x and x vary directly as the squares of the bases or as 6º, 6º.
1000
The simplest form of slide rule will at once perform this multiplication, obviously
if the base is very short, small differences in x will be measured by very small
movements of a or very small advances of the cylinder, at least, so small that it
would be necessary to push it forward by a micrometer screw as the hand will be
too rough an instrument for the purpose. The alternative is thus:-First, a short
base with delicate micrometer movement to push forward the cylinder; second, a
longer base admitting the more rough and ready method of adjusting the cylinder
by the hand so as to reflect the head of the staff A into observer's eye at B. With
a carefully prepared tape 31 yards 1'10.38" can be measured as accurately as
20 yards or 30 yards, that is to say, with as little error.
=
The spiral scale is graduated to give actual values of x for different length
of a as near each other as possible (on the assumption that ba 1,000) to the
shortest distance admitted of by the working length of cylinder, but if the base
actually used i.e., b, be other than ✓1,000, and the distance read off on the scale
be (x), then x (1,000) =x, the true distance. N.B. This method of graduating the
spiral scale is not in any way intended to restrict the base to 1,000, but only to
x =
a
-
perform mechanically the operations required for working out the equation
6 being assumed = 1,000, so that for any other base the only remaining
operation required is really nothing but multiplying the recorded distance by the
square of the new base, and assigning the proper decimal point which at ouce gives
the true distance of observed object.
The tape prepared for 1,000 could be marked off also for distances of 10, 20,
and 30 yards from which by a second measurement distances of 40 and 50 yards
could be measured, giving squares of 100-400-900-1,600, and 2,500 yards, all
casy numbers of the slide rule to multiply with.
Figures 6 and 7 represents a stand with one central upright and three struts for
supporting the range finder before explained, or the modified construction of the
range finder shown at Figures 8 and 9. To remove this stand from position pull
up in succession the point of each strut out of ground, disengage it at C and pull
up the M end of the strut till it is stopped by the catch C², which is round
cornered.. Then fold in the leg N; finally, strap all together round the central
upright.
The mirror in the modified construction is a double one, as in Figure 10, reflecting

page_text: right and left, fastened at right angle also into grooves in a metal triangle
attached to screw; the mirror Y is half the height Z. The mirror is at centre of
gravity inimediately over B and pointing to 3,000. In this position it acts as an
optical square when set down at A', B¹.
Modified construction of range finder; Figures 8 and 9 consists of a metal tube
over 3 feet long and the of an inch diameter. Through this tube from end to
end is a steel rod 2/rds of which carry a threaded screw (i.e., from m to n) to
which is attached the shank of the double mirror, reflecting right and left at an
angle of 45° to the axis. The mirror moves from m to n and carries at each
side of tube a pointer indicating in yards at the spot pointed to the value of the
equation +α =
h
=
This equation, shown by the diagram in Figure 11, representing the distance B X
is thus obtained; X, A, B, is a right angle by construction, and B, A,
30 yards,
by Prop. XXXI., 3rd book Euclid, BX diameter of circle passing through
points B, A, and X, and A, C, , right line in circle; Prop. III.; and by
Prop. XXXV., X C x C B, or x x a = C². Then acc: and a, x = 0º
ba, and x = or x =
8' a'
a
a
-
=
a, add to each side + a and x + a =
As will be shown A C is perpendicular to BX.
b
or B X.
The instrument is graduated the entire length of 3 feet m¹ or p (zero point) to n
virtually and actually, 30 divisions to an ineh-1,080 divisions, of these 756 are
engraved on the limb of the instrument (i.e., from m to n) commencing at No. 324,
where value of equation representing + α = 3,000, and terminating at n,
No. 1080, where x + a = showing B X =.900 yards.
a
16th day of
The limb of
Should the
The limit of graduations is from 900 to 3,000 yards. The present extended
range for which the "Holmes," special auxiliary sights patented on the
October 1878, No. 4107, are graduated for the Henri-Martini rifle.
the instrument is graduated in yards for and between these distances.
range finder be required to measure a range or distance, shorter or longer, say from
225 to 9,000 yards, by a very simple process it is at once applicable.
The mirror is so arranged that when drawn back to point at either side to 3,000
yards, the reflection is immediately over centre of stand, and thence acts as an
optical square to lay out a right angle either side.
The instrument carries over tube, an open cylinder with eye piece for reflected
vision in mirror, and over this a telescope for direct vision over mirror of X., The
tube rests on an ebonite plate in which at p zero point is a peg, and on this tube
pivots some 2° or 3°.
This pivotting motion is regulated by a milled head and short endless screw, the
ebonite being clamped to stand when X is approximately sighted.
The stand is a central upright, the point of which fixed in ground placed vertical
by a plumb line or cross level, and supported in position steadily by tripod legs,
which fold to central upright on top of which the ebonite plate with tube is bolted
when in use furnished as stated with a clamp. The instrument is so arranged that
centre of gravity is immediately over centre of stand, as also is centre of mirror
with reflection showing g, x + α = 3,000.
The zero point p. being necessarily nearly 11 inches in rear of centre of gravity
where range finder rests and pivots, and as it is indispensable that this point
should always be directly over A or B, as the case may be, a tentative base has
been decided on, each end terminating where stand is fixed, as shown in diagram.
The central point is placed in ground fixing A', and A¹, B¹, becoines the tentative
base at right angles to A¹, X; A¹, B¹, is then measured 30 yards and using mirror
as optical square. Range finder is placed parallel to A X. Thus, when in position
at either A or B by suspending a plumb line on hook under zero point p..
accurately insuring the pivotting point being over A or B.
"

page_text: MODUS OPERANDI.
The distance from vicinity of any place B to X being required; pace right or
left 30 yards (at present we will say to the left), slightly inclining to your left in
pacing so as on arrival at A¹ the angle X, A', B, may approximate a right angle,
set up stand point in ground A', fix range finder on it directed to X, clamp ebonite
to stand, and moving milled head sight X accurately; then clamp to ebonite,
attach plumb line to hook at p and mark A in ground, run out a cord at right,
angles to A', X, and with assistant measure it carefully 30 yards.
Mark B on ground and remove to it stand with instrument, first placing
painted staff at A; then with mirror fix tube parallel to A, X, and clamp, ebonite
to stand, thus fixing p which is the pivotting point over B. Then by turning
milled head pivot tube on ebonite until X is on telescope wire. The clamp tube
to ebonite and turning screw handle propel mirror until A is reflected on centre
of mirror; then read off from limb of instrument the distance of X in yards or
value of equation + α = The range finder being intended as an accom-
paniment to and graduated for "The Holmes' Special Auxiliary Sights," which
have proved beyond dispute the capability of the Heuri-Martini rifle being effective
at 3,000 yards.
b
For a shorter distance than 900 yards a range finder is unusual. For many
purposes a more extended range may be desired, a brief explanation is appended
how to apply.
The range finder as at present graduated to the measurement of any distance
from 225 to 9,000 yards.
Required to measure a range of say 6,000 yards there or there-abouts. From a
point A¹, X being distant object, and the vicinity of B the ground from which the
measurement is sought; set off a right angle X, A, B, as a diagram, Figure 13,
and on A, B, measure off a base 60 yards, marking the middle point A by a pole or
staff set in ground. Place stand with range finder at B, and looking at X being A
reflected to centre of mirror, multiply distance recorded by 2 and it will give real
distance. The actual distance recorded on graduated scale being of course that of
B X-X being an imaginary point which has not to be marked on the ground, the
distant X¹ being in the same line kindly answering for the purpose of being shot at
from B. The demonstration of the above is obvious (by diagram) X', A, B, and
X, A, B, being similar triangles.
It is also obvious that by this method distances can be measured from 1,800 to
6,000 yards, but of course the increments or decrements of distances will be twice as
large as with smaller base. Similarly, if the base A¹, B, is made 90 yards, A, B,
must be measured 30 yards from B, but result multiplied by 3.
-
=
In a similar manner for smaller distances under 900 yards, as by diagram
Figure 14, make A B 10 yards, or 20 yards measure A B 30 yards, and set up
a staff at A, which of course will be beyond A', and the imaginary X will be beyond
X, divide the recorded distance by 3 or 2, as the case may be, to get true distance.
Having now described the nature of the said Invention and in what manner the
same is to be performed, I declare that I claim,―
First. The apparatus hereinbefore described and shown in Figure 1 of the
Annexed Drawings as a range finder.
Secondly. The apparatus hereinbefore described and shown in Figure 4 of the
annexed Drawings as a range finder.
Thirdly. The apparatus with exterior spiral scale for the purpose described and
shown in Figure 5.
Fourthly. The apparatus shown in Figures 6, 8, and 0, composed of an adjustable
screw, double mirrors, and two telescopes one above the other, the whole forming a
range finder, as set forth.

page_text: Fifthly. The special form of stand, as shown in Figures 6 and 7, as and for the
purpose described.
In witness whereof, I, the said James Gustavus Hamilton Holmes, have
hereunto set my hand and seal, this 26th day of February, in the year of
our Lord One thousand eight hundred and eighty.
J. G. HAM. HOLMES. (L.S.)
Lt.-Colonel H.P., 12th Royal Lancers,
Milber View, Newton Abbot,
S. Devon.
26th February, 1880.
In presence of
EMILY ROWLANDSON,
of 9, Markwick Terrace,
St. Leonards on Sea.