Year: 1886

page_text: Date of Application, 9th July, 1886.
Complete Left, 12th Apr., 1887.
Complete Accepted, 8th July, 1887
RESERV
I, NEVILLE LLOYD WALFORD of Shoeburyness in the county of Essex, Major in
the Royal Artillery, do hereby declare the nature of this Invention to be as follows:-
The object of my invention is to provide an improved means of ascertaining the
distance or range of any object from a given point, more especially with regard to
military requirements.
The improved apparatus which I employ for this purpose is constructed and used
substantially as follows;
Near the point from which the range or distance is to be measured, I mount upon
a tripod, post or other convenient support a short telescope, hereinafter called "the
main telescope." The said telescope is provided at the focus of the eye-piece with a
vertical line, but the said line, in place of being permanently fixed in position with
regard to the axis of the telescope in the usual manner, is, (being engraved or
otherwise fixed on glass,) capable of being moved horizontally in guides at right
angles to the said axis.
The sliding motion is given by means of a screw, preferably of quick pitch, which
is provided with a graduated head.
By this means the observer can traverse the vertical line across the field of the
telescope, within certain limits. In measuring a range the line is placed at the
extreme right hand position, so that a fixed pointer corresponds with a zero mark
upon the aforesaid graduated head.
By the use of a tangent motion, or other suitable device, the telescope is moved
until the said line coincides with the object of which the distance is to be obtained.
A second or smaller telescope is mounted upon the holder of the main telescope at
about right angles thereto, and is provided with two parallel horizontal lines and one
central vertical line, engraved or otherwise fixed on glass. The observer now looks
through this small telescope, while an assistant at a few yards distance, provided with
a staff having a clear vertical line marked on the side thereof, moves the said staff
until the line thereon coincides with the vertical line in the small telescope.
The staff is fixed and left in this position.

page_text: In place of a staff, I occasionally prefer to employ a tripod having the aforesaid
line marked on one of the legs thereof, as being more easy to adjust on hard ground.
The leg having the line marked thereon shorter than the other two, that it may
stand vertically.
The telescopes are now removed from the tripod and placed upon another tripod, at
a distance therefrom averaging from about ten to one hundred yards, according to the
length of the range to be measured, or the nature of the ground.
The distance between the said tripods constitutes my base line, and it will be
observed as one of the advantages in the use of my instrument that an observer is not
confined to a fixed base line for all ranges, nor is the base a constant proportional of
the range.
A device, consisting of a circle or ring with two diagonals, is placed upon the first
tripod, and the telescopes and second tripod are so adjusted, that on looking through
the small telescope, the vertical line in it, the intersection of the diagonals on the
above device, and the black line on the staff or tripod will coincide.
The object being to ensure the axis of the small telescope being in the same line as
when in position on the first tripod, and consequently the parallelism of the axis of
the main telescope with its axis when in the first position also.
On now looking through the main telescope the distant object is seen to one side of
the vertical line, (right or left according as the base is set to left or right of the first
point,) the space between them being equal, on the scale to which the objects are
represented in the telescopic field, to the base line between the tripods.
By means of the aforesaid screw, the vertical line in the main telescope is now
moved until it again coincides with the distant object, and the reading on the
graduated head taken against the fixed pointer.
The said head is so graduated that the number thus obtained, when multiplied by
the length of the base in yards, gives the range in yards.
The base may be measured directly by a tape, but as this may frequently be difficult
on account of the nature of the ground, I occassionally prefer to employ the following
arrangement.
A staff, jointed for portability, is planted at the first tripod, from which the length
of the base is read off, the said staff being so graduated that the length of the base is
read from that portion of it which is included between the two horizontal lines of the
small telescope, when observed by the latter from the other end of the base.
In practice the lower line, is made to coincide with the upper edge of a white ring
fixed on the staff, which marks the commencement of the graduations; an assistant
then moves a white sliding ring up or down the staff, until its lower edge coincides
with the upper line of the telescope; the length of the base is then read off from the
graduated staff.
It will be seen that the services of an assistant are not indispensable, but merely
enable an observation to be made more rapidly.
Dated this 0th day of T... 100c
AMBROSE MYALL, C.E.,
Agent for the Applicant.

page_text: I, NEVILLE LLOYD WALFORD of Shoeburyness in the ounty of Essex, Major in
the Royal Artillery, 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 :—
The object of my invention is to provide an improved means of ascertaining the
distance or range of any object from a given point, more especially with regard to
military requirements.
The improved apparatus, which I employ for this purpose, according to one method
of carrying out my invention, is constructed and used substantially as follows;
Near the point, from which the range or distance is to be measured, I mount upon
a tripod, or other convenient support a short telescope hereinafter called the "main
telescope."
The said telescope is provided at the focus of the eye-piece with a vertical line, but
the said line, in place of being permanently fixed in position with regard to the axis
of the telescope in the usual manner, is (being engraved or otherwise fixed on glass,)
capable of being moved horizontally in guides at right angles to the said axis.
The sliding motion is given by means of a screw, preferably of quick pitch, which
is provided with a graduated head.
By this means the observer can traverse the vertical line across the field of the
telescope, within certain limits. In measuring a range the line is placed at the
extreme right hand position, so that a fixed pointer corresponds with the point of
initial graduation upon the aforesaid graduated head. By the use of a tangent motion,
or other suitable device, the telescope is moved until the said line coincides with the
object of which the distance is to be obtained.
A smaller telescope is mounted upon the main telescope, at about right angles
thereto and provided with two parallel horizontal lines and one central vertical
line, engraved or otherwise fixed on glass. The observer now looks through this
second telescope, while an assistant at a few yards distance, provided with a staff
having a clear vertical line marked on the side thereof, moves the said staff until the
line thereon coincides with the vertical line in the small telescope.
The staff is fixed and left in this position. In place of a staff, I occassionally prefer
to employ a tripod having the aforesaid line marked on one of the legs thereof as
being more easy to adjust on hard ground. The leg having the line marked thereon
is shorter than the other two, that it may stand vertically. The telescopes are now
removed from the tripod and placed upon another tripod at a distance therefrom
averaging from about ten to one hundred yards, according to the length of the range
to be measured, or the nature of the ground.
The distance between the said tripods constitutes my base line, and it will be
observed as one of the advantages in the use of my instrument that an observer is not
confined to a fixed base line for all ranges, nor is the base a constant proportional of
the range.
A device, conisting of a circle or ring with two diagonals is placed upon the first
tripod, and the telescopes and second tripod are so adjusted, that on looking through

page_text: the small telescope, the vertical line in it, the intersection of the diagonals on the
above device, and the black line on the staff or tripod will coincide. The object being
to ensure the axis of the second telescope being in the same line as when in position
on the first tripod and consequently the parallelism of the axis of the main telescope
with its axis when in the first position also.
On now looking through the main telescope the distant object is seen to one side of
the vertical line, (right or left according as the base is set to left or right of the first
point) the space between them being equal, on the scale to which the objects are
represented in the telescopic field, to the base line between the tripods.
By means of the aforesaid screw the vertical line in the main telescope is now
moved until it again coincides with the distant object, and the reading on the
graduated head taken against the fixed pointer.
The said head is so graduated that the number thus obtained, when multiplied by
the length of the base in yards, gives the range in yards.
The base may be measured directly by a tape, but as this may frequently be
difficult on account of the nature of the ground, I occassionally prefer to employ
the following arrangement.
A staff, jointed for portability, is planted at the first tripod, from which the length
of the base is read off, the said staff being so graduated that the length of the base is
read from that portion of it which is included between the two horizontal lines of
the small telescope, when observed through the latter from the other end of the base.
In practice the lower line is made to coincide with the upper edge of a white ring
fixed on the staff, which marks the commencement of the graduations; an assistant
then moves a white sliding ring up or down the staff until its lower edge coincides
with the upper line of the telescope; the length of the base is then read off from the
graduated staff.
It will be seen that the services of an assistant are not indispensable, but merely
enable an observation to be made more rapidly.
A modified form of my apparatus which in practice I prefer to use is illustrated by
the accompanying four sheets of drawings, in which Figure 1 is a perspective view of
the telescopes mounted upon a tripod, Figure 2 is a perspective view of a vane or
sighting device also mounted on a tripod, Figure 3 is an elevation of the front end of
the main telescope with the eyepiece removed shewing the mechanism employed for
moving the aforesaid vertical line in the focus of the said eyepiece and Figure 4 is a
diagram or plan explaining the theory and method of using the apparatus.
Similar letters of reference denote similar parts throughout the figures.
A is a tripod or other convenient support having a telescope B hereinafter called
the "main telescope" mounted thereon. The said telescope B is provided at the
focus of the eyepiece C with a vertical line D, figure 3, but the said line, in place of
being permanently fixed in position with regard to the axis of the telescope, in the
usual manner, is, (being engraved or otherwise fixed on a glass slip E) capable of
being moved horizontally in guides F F at right angles to the said axis.
The sliding motion is given by means of a screw H preferably of quick pitch,
which is provided with a graduated head J.
Springs K K are employed to take up any lost motion in the screw H.
By this means the observer can traverse the vertical line D across the field of the
telescope within certain limits. In measuring a range the said line is placed at the
extreme left hand (or right) position, so that a fixed pointer L, Figure 1, corresponds
with the initial point of graduation upon the aforesaid graduated head. By the use
of a tangent motion M, or other suitable device, the telescope is moved until the said
line coincides with the object of which the distance is to be obtained.
A second telescope N, is mounted upon the main telescope B, at about a right
angle thereto, and is provided with a fixed central vertical line, engraved or otherwise
fixed on glass.
The instrument is then lifted from the tripod A and a bar O fitted with two circular
vanes P and Q (P being pierced and bearing two vertical black bars or lines P¹ P¹,
and Q having one black line Q¹ on a white ground,) is placed upon the said tripod A.

page_text: The head of the tripod is formed square, or circular with a feather, to fit into a
similarly shaped socket on the telescope and vane, or is otherwise so arranged that
the line joining the centre of the two vanes is in the same vertical plane as was the
axis of the small or cross telescope N.
The instrument is then placed upon another tripod at a distance from the first of
from 10 to 100 yards, according to the length of the range to be measured or the
character of the ground.
The distance between the said tripods constitutes my base line, as in the former
case.
The instrument when on the second tripod is so adjusted, that on looking through
the small telescope N the vertical line in it coincides with the black vertical line Q₁
on the farther vane Q, as seen through the space between the two vertical black
lines P P on the nearer vane P. The object of this adjustment is to ensure the axis
of the small telescope being in the same line as when in position on the first tripod A
and consequently the parallelism of the axis of the main telescope B with its axis when
in the first position also.
On now looking through the said main telescope the distant object is seen to one
side of the vertical line D (right or left according as the base is set to left or right of
the first point,) the space between them being equal, on the scale to which objects are
represented in the telescope field, to the base line between the tripods.
By means of the aforesaid screw H the vertical line in the main telescope is now
moved until it again coincides with the distant object, and the reading on the
graduated head is taken against the fixed pointer.
The said head is so graduated that the number thus obtained, when multiplied by
the length of the base in yards, gives the range in yards.
The base is preferably measured by the following arrangement; A staff, jointed for
portability, is planted at the first tripod A; this staff is, as regards the upper part of
it, painted in alternate bands of black and white, each band being 9 inches, or a
quarter of a yard, in length. The base is obtained from this as follows; That portion
of the eyepiece C of the main telescope B, which carries the vertical line D and the
graduated head J, is brought vertical, (it was horizontal while taking the range) the
head is set to zero and the line D is made, by a tangent or other suitable motion, to
coincide with the lower edge of the lowest band on the staff; the graduated head J is
then turned until the line D coincides with the upper edge of the highest band, and
the length of the base in yards is read off the graduated head.
Should the base be very short, under 40 yards, the line will be traversed to the
centre of the bands, and the reading on the head divided by 2 will give the length of
the base; or it may be moved over one band only, when the length of the base will
be one-fourth of the reading on the graduated head.
Should an assistant he available, who can hold the staff horizontally, there will be
no need to change the position, as mentioned above, of that portion of the eyepiece of
the main telescope which carries the vertical line and the graduated head.
The services of an assistant, as in the former case, are not indispensable, but merely
enable an observation to be made more rapidly.
The device shown in Figure 2 consisting of the bar O and vans P and Q practically
combines in one piece of apparatus the vertical staff and ring with diagonals, as
described in connection with the first form of my apparatus, thus simplyfying the
instrument and enabling an observation to be taken more rapidly. The vanes P and Q
fold down upon the bar O, when not in use, and the pivot on which P turns has a fine
screw thread cut at each end, provided with lock-nuts to enable P to be accurately
adjusted in relation to Q. Any other suitable device may be employed to give such
adjustment and I do not necessarily confine myself to the exact mechanical means
shown in Figure 3 for giving motion to the line D in the focus of the eyepiece in the
main telescope B.
In figure 4 let R be the object of which the range is desired. The instrument
shewn in figure 1 is placed at any point S, from which it is desired to find the range,
and the line D in the large telescope B is directed upon R, the graduated wheel' J

page_text: being previously set to zero. The axis of the small telescope N then lies in the line
of the intended base S. T. The instrument being lifted from the tripod, the vane
shewn in Figure 2 is set there in its place; the centre line of the vane then is in the
same vertical plane as was the axis of the small telescope N and thus also lies in the
line of the intended base S, T. When therefore the instrument is put up at T. (at
any convenient distance from S) in such a manner that the axis of the small telescope N
is in the prolongation of the centre line of the vane, the long telescope will be parallel
to its former position R. S. and the line in its field, if, the graduated wheel be still at
the initial graduation, will be directed on a point U, the distance U R being equal
to S, T. As the base S T will be very small in proportion to the range S, R, the
point R, will still be in the field of the large telescope B, but will be on one side
of the line D in that field.
The graduated wheel is then turned until this line
again covers the point R; the reading on the wheel then gives the co-tangent
of the angle U, T, R, (or T, R, S.); or in other words gives the range in terms of
the base.
For example; Let S, T, be 25 yards, and the reading be 87.5. Then the range
equals (25x87-5) yards or 2187.5 yards. Or let S, T, be 37-25 yards and the
reading be 107.25. The range equals (37-25 × 107.25) yards or 3995 yarda.
The wheel J is graduated practically by directing the telescope B at an object of
known length, say 1 yard, at distances which are various multiples of a yard; for
example, the graduated wheel being at its initial graduation the line in the field is laid
on one end of an object 1 yard in length, it is then traversed until it coincides with
the other end, if the distance from the telescope to the object be 40 yards, the pointer
will then be opposite to that spot on the wheel which should be graduated 40; if at
60 yards to the point which will be marked as 60.
Having now particularly described and ascertained the nature of said invention
and in what manner the same is to be performed, I declare that what I claim, is:—
(1.) In a range finder, consisting of a main telescope B and cross telescope N, the
combination therewith of a line D capable of motion within the focus of the eyepiece
of the main telescope by means of a screw H, or other suitable mechanical device,
having a divided head J to measure the amount of such motion, substantially in the
manner and for the purposes as herein set forth.
(2.) The apparatus consisting of a bar O with vanes P and Q provided with
lines P¹ P and Q₁ for use in combination with the instrument, as set forth in the
preceeding claim, for enabling the said instrument to be adjusted for position at
the end of a base line, substantially in the manner and for the purposes as herein set
forth.
(3.) The apparatus consisting of a staff with a vertical line marked thereon and a
ring with diagonals, for use in combination with the instrument, as set forth in the
first claim, for enabling the said instrument to be adjusted for position at the
end of a base line, substantially in the manner and for the purposes as herein set
forth.
(4.) The graduated staff for use in combination with the main telescope of the
instrument, as set forth in the first claim, for the measurement of a base line,
substantially as herein set forth.
(5.) The graduated staff provided with a sliding ring for use in combination with
the cross telescope of the instrument, as set forth in the first claim, for the measure-
ment of a base line, substantially as herein set forth.
AMBROSE MYALL,
21, Cockspur Street, S.W.,
Agent for the Applicant.