IMPROVEMENTS IN TELEMETERS OR INSTRUMENTS FOR FINDING RANGES AND DISTANCES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I THOMAS BOLTON of Calcutta in the East Indies Mathematical Instrument
Maker to the Government of India do hereby declare the nature of the said
invention for "IMPROVEMENTS IN TELEMETERS OR INSTRUMENTS FOR FINDING
RANGES AND DISTANCES" to be as follows:-
This invention relates to an instrument for measuring distances, finding ranges,
surveying and similar operations. Said instrument consists substantially of say
two pairs of cross telescopes set at suitable angles to each other working on a
graduated base-bar from which the measurement can be read off.
The instrument may conveniently be constructed as follows:-
In one pair (there being two pairs of telescopes) the telescopes are set at right
angles to one another and this pair is mounted. on one end of the base bar. The
other pair are set at an angle somewhat less than a right angle to each other. This
second pair is so mounted as to be capable of sliding on the base bar.
Both pairs are fitted with suitable adjusting gear so that they may be exactly
collimated.
The base bar has suitable graduations (corresponding to yards say) marked upon
it and is fitted with a vernier so that the indications may be accurately road off.
The whole instrument may conveniently be supported on two tripod stands.
In use one of the telescopes. (say that at the left hand side of the instrument)
which is at a right angle with the one which forms its pair is pointed toward the
object or point whose distance from the apparatus is to be measured, this is the
one collimating telescope. The other collimating telescope is now adjusted till the
cross-lines of both these telescopes coincide.
The object is next focussed in the acute angle telescope and bisected with the
cross lines by means of the adjusting gear.
The measurement may then be read off from the scale which is so graduated in
relation to the suitably chosen acute angle that a division upon it may correspond
to a predetermined distance say 1 yard of base for 500 of perpendicular for sur-
veying purposes; or 1 yard of base to 2000 yards of perpendicular for infantry
range finding, or 1 yard of base for 6000 perpendicular in artillery range finding.
The collimating telescopes point towards each other and are focussed to parallel
rays and their cross lines always intersect when the telescopes are in adjustment.
Dated this 7th day of October 1884.

page_text: COMPLETE SPECIFICATION.
13
I THOMAS BOLTON of Calcutta, India, Mathematical Instrument Maker to the
Government of India, do hereby declare the nature of this invention for "IMPROVE-
MENTS IN TELEMETERS OR INSTRUMENTS FOR FINDING RANGES AND DISTANCES
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
The Collineameter is an instrument for finding ranges and distances by means
of a short base and two telescopes fixed in inclination and kept in the relative
positions by collimating telescopes the ranges and distances being read directly
from the scale on the base bar.
.
The instrument may be briefly described as consisting of two pairs of cross 1
telescopes. In one pair the telescopes are set at right angles to each other and are
fixed at one end of the baso bar. The other pair of telescopes ard set at an angle
a little less than a right angle to each other and are arranged to slide on the base
bar. Connected also with each pair of telescopes are the necessary mechanical
slides and screws required for accurately collimating and directing the cross 1
telescopes to the distant object.
The base bar of suitable length is graduated into yards and with the assistance
of a vernier attached to the moveable pair of telescopes the distance of an object
can be at once accurately read off.
The whole instrument is supported upon two light tripod stands.
The accompanying drawings will further describe the instrument.
DESCRIPTION OF THE DRAWING.
M is the mahogany base bar with an upper graduated brass plate and rack to
move telescopes T. T. along the base bar..
T. T. one pair of cross telescopes securely fixed together and arranged to slide on ?
base bar M and set to each other at an acute angle which would be as one yard of
base to 500 yards of perpendicular in a right angled triangle when the instrument
is intended for surveying purposes or at an angle equal to 1 yard base to
2000 yards perpendicular when intended for Infantry range finding or 1 yard base
to 6000 yards perpendicular when intended for Artillery range finding and so
forth A. B. scrows for adjusting collimating telescope T sideways.
P pinion for moving telescopes T. T. along the base bar M.
E screws to raise or lower collimating telescope T.
D, screws to raise or lower acute angled telescope T.
Y supports for telescopes.
TT one pair of cross telescopes fixed at one end of the base bar M and set at
right angles to each other.

page_text: S. slide on which telescope T¹ T' and the end of base bar M rest and for
moving the vertical cross lines of right angled telescope T on to the object.
R tripod stands.
X conical pin to fit into tripod R and support base bar M.
TT two collimating telescopes pointing towards each other and focussed to
parallel rays, their cross lines must always intersect each other when in
adjustment.
T. T. Right angled and acute angle telescopes crossing the collimators and
having rack focussing tubes to focus on the object, whose distance is required.
1st The entire instrument is placed on the tripod stands with the right angle
telescope T pointing towards the distant object whose range or distance is
required.
2nd The cross lines of the telescopes T should be made to pass and bisect the
object by moving the rack of the telescope and the adjusting screws S and C.
3rd Looking into the collimating telescope T move the adjusting screws A and B.
till the cross lines of both collimating telescopes T and T¹ coincide.
4th Focus the object in the acute angled teloscope T and bisect it with the cross
lines by moving the adjusting screw D and pinion P.
5th To ensure accuracy the results of the operations 2. 3 and 4 may be looked
at again and any derangement rectified before reading off the range or distance
from the vernier and scale on the base bar M,
Having thus described the nature of my instrument and the method of ascer-
taining a range or distance of any object by it I further wish to state that I do
not confine myself to the precise size of the instrument or extent of the acute angle
or the manner of graduations on the base bar all of which may vary according to
the particular work for which the instrument is designed but I claim
An Instrument for measuring distances consisting of two pairs of cross telescopes
set at suitable angles to each other working on a graduated base bar from which
can be read off the rango of a distant object substantially as herein before set forth
and shown.