IM- PROVEMENTS IN MEANS AND APPARATUS FOR MEASURING ANGULAR AND ACTUAL DISTANCES
Year: 1863

page_text: LETTERS PATENT to Patrick Adie, of the Strand, in the County of
Middlesex, Mathematical Instrument Maker, for the Invention of "IM-
PROVEMENTS IN MEANS AND APPARATUS FOR MEASURING ANGULAR AND ACTUAL
DISTANCES"
Sealed the 11th September 1863, in pursuance of an Order by the Lord
Chancellor and dated the 4th March 1863.
COMPLETE SPECIFICATION filed by the said Patrick Adie at the
Office of the Commissioners of Patents, with his Petition and Declaration,
on the 4th March 1863, pursuant to the 9th Section of the Patent
Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PATRICK
ADIE, of the Strand, in the County of Middlesex, Mathematical Instrument
Maker, send greeting.
WHEREAS 1 am in possession of an Invention for "IMPROVEMENTS IN
MEANS AND APPARATUS FOR MEASURING ANGULAR AND ACTUAL DISTANCES," and
have petitioned Her Majesty to grant nuto me, my executors, adminis-
trators, and assigns, Her Royal Letters Patent for the same, and have made
solemn declaration that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said Patrick Adie, do hereby declare that
the following complete Specification under my hand and seal fully describes
Doice d

page_text: and ascertains the nature of the said Invention, and in what manner the same
is to be performed, in and by the following statement :-
The improvements relate to the arranging of the instruments invented and
patented by me, A.1). 1860, 10th February, No. 357, in such a way as to get
rid of the errors of eccentric and other parallar.
For this purpose in the first arrangement applied to measuring angular
distances, I adopt two similar telescope object ends, one above the limb and
the other below, the lower one being fixed to the limb and the upper one
with a veneer attached, reading full degrees and travelling over the length of
the arc.
To connect these, the upper telescope has a hollow male centre at
right angles to and in one piece with itself, and the lower one a female centre
also in one piece with and at right angles to the lower telescope. At the
junctions of the male and female centres and their respective telescope tubes
are placed a reflecting prism or other reflector in each, which sends the rays
received from their respective object glasses through the hollow centre and
towards each other, these rays being then received on two smaller reflectors
mounted on an adjustable arm to correct for eccentricity and parallelism, each
reflector occupying half the field of the eye-piece,which then receives the rays.
A position is given to the eye-piece always intermediate to the angle of the
two telescopes by means of two levers, each attached to one end to the object
ends of the telescopes and at the other end to a sliding piece on the eye-tube,
and turns on a centre round the outside of the female or lower telescope centre,
and to this the interior or half prisms are attached with their adjustments.
By this means, having the two telescopes and their reflectors symetrical, I get
rid of all parallar and get parallel rays into the eye-piece. The improvements
may be applied also when only plain sights are used. 1 also adapt a small
reflector fixed to the eye tube centre, and and brought by an arm over the
centre of the instrument; this I use as a fiuder and as a quick measurer
of the angle, both arrangements reading in full degrees on the limb.
The improvements relate, secondly, to the arranging of the reflectors in the
second part of my Invention, when the actual distance of an object is measured
by the angle formed by the cones of rays of the two telescopes, so as to get rid
of parallax and bring the rays from both object glasses parallel into one eye-
piece. For this purpose I attach the object glass of the moveable telescope
and the reflector behind it to the inuer tube at the end furthest from the centre,
the reflector behind the other object glass and the object glass itself being
made a fixture to the outer tube. The centre round which the interior
telescope turns I place near or in the middle of the instrument. The rays
from both object glasses, passed towards the centre by the above reflectors, are

page_text: then received by two half reflectors, either one before the other or their ends
opposite to one another when used in a hollow centre. For facilitating the
fixing and adjustment of these prisms, I attach the front one to the outside of
the outer tube, or if both are used in a hollow centre I fix both from the
outside.
But that the nature of my Invention and means I adopt in carrying the
same into effect may be better understood, I will proceed to describe the
Drawings annexed, in the various Figures of which the same letters are used
to indicate like parts wherein they occur.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents a side view in section of the first part of my improve-
ments; Fig. 2, the same in plan.
A, the upper telescope; B, the under one; e, the tube carrying the eye-
piece, which is fixed to n,, which is a female centre working outside the
centre m, m; L is the limb fixed firmly to m, m, into which the lower
telescope is fixed; the upper telescope A is fixed to h, h, the interior hollow
male centre R, R', the reflecting prisms with usual adjustments in the
telescope tubes, sending the rays at right angles towardsp³.p²; these reflectors
or prisms are mounted on the arm, which is attached to n, n, and made
adjustable as to centreing and parallelism by pushing and pulling screws ath,k.
The two levers cand c' are each jointed at one end to o, which slides on the
tube outside the eye-piece tube e, and are jointed at the other ends to two
arms and ct, which arms are fixed to the telescope tubes a and b, so that
when a is moved round its centre n, n, in the centre m, m, I always holds a
position midway between the two (on the other side of the centre). Thus I
correct for the very large eccentric parallar which existed in the first arrange-
ment, and with the adjustments at h, k, and the strong steady arrangements of
centreing, I have effected great improvements. is a reflector, the shaded
portion being silvered, the other half plain, fixed on a pillar to n, n; this, by
moving only through half the angle, fixes the telescopes quickly to the angle,
and is useful as a rougher instrument, and is read in full degrees on the
limb.
Figs. 3 and 4 represent a side view and plan in section of the second part
of my improvements, and Fig. 5 shows the means I adopt for fixing the front
prism from the outside, both prisms being so fixed when these are in a hollow
centre.
a, a, is the outside telescope tube; a¹, the object glass fixed to it, and p, the
prism or other reflector to send the rays to the middle of the tube; b, b, is

page_text: the interior telescope tube; 6', its object glass fixed firmly to it; pl, its prism to
bend the rays, also fixed to b, b, and both moving with it; p³ receives the rays
from p', and sends them into half the eye-piece a²; 4 receives the rays from p
and sends them into the other half of eye-pieces; c and c¹ are the inner and
outer centres placed either near or in the middle between a¹ and b¹; gand e, a
scale and vernier, reading in degrees the angles of the telescopes when directed
at an object; T, the tangent screw for setting. Thus by giving the greatest
motion to the object glass 61 and its prism p' and the least to the centre prism,
I correct for what was before a detrimental parallar in this part of my
improvements, and by fixing p3, represented at Fig. 5, from the outside, I
greatly facilitate the construction.
Having thus described the nature of my said Invention, and in what
manner I carry the same into effect. I would have it understood that I do not
confine myself to the precise details shewn and described, as these may be
varied; but what I do claim is,―
The means of reading angles in full degrees, without parallar.
And I also claim the means of using two telescopes directed to the same
or different objects and obtaining parallel rays into one eye-piece, and so
getting a correct simultaneous observation, as applied and described in Figs. 1
and 2 and in Figs. 3, 4, and 5.
In witness whereof, I, the said Patrick Adie, have hereunto set my band
and seal, this Fourth day of March, in the year of our Lord One
thousand eight hundred and sixty-three.
PATRICK ADIE. (L.S.)