IMPROVEMENTS IN SURVEYING INSTRUMENTS."
Year: 1871

page_text: LETTERS PATENT to Henry Davis Hoskold, of Cinderford, in the
County of Gloucester, Mining & Civil Engineer, and John Emanuel
Winspear, of Kingston-upon-Hull, in the County of York, Mathe-
matical Instrument Maker, for the Invention of "IMPROVEMENTS
IN SURVEYING INSTRUMENTS."
PROVISIONAL SPECIFICATION left by the said Henry Davis Hoskold
and John Emanuel Winspear at the Office of the Commissioners of
Patents, with their Petition, on the 8th May 1871.
We, HENRY DAVIS HOSKOLD, of Cinderford, in the County of Glou-
cester, Mining and Civil Engineer, and JOHN EMANUEL WINSPEAR, of
Kingston-upon-Hull, in the County of York, Mathematical Instrument
Maker, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN. SURVEYING INSTRUMENTS," to be as follows:-
This Invention relates to a new surveying instrument for measuring
angles in field and underground work.
The instrument is made with a divided limb, and is mounted with a
telescope which revolves, and thus becomes a transit instrument of great

page_text: power. Its particular form renders it well adapted to be used as a
zenith telescope, and also for connecting underground surveys to those
on the surface directly by means of the telescope without magnetic
bearings. In this instrument the length of telescope does not regulate
the height, as a small instrument of this class may be made to carry a
telescope of equal length and power with some of the larger instruments
of the old type. The horizontal axis carrying the telescope and vertical
circle is mounted close down on low bearings on the upper vernier plate.
These bearings, axis, and all other internal arrangements are covered up
by a magnetic compass box, which also is of the same diameter as the
graduated limb. The needle carries a silver floating circle with a vernier
at each end, and it rests on a recess cut in the edge of the inner divided
circle. It is thus prevented from rocking or vibrating unduly. The
telescope is fixed in a stout cylindrical ring at one end of the horizontal
axis, and made to rotate in it vertically for the purpose of "collimation."
The vertical circle is constructed with a conical limb, and the gradua-
tions are put on the edge thereof instead of as usual against the side of
-it; -there-is-consequently greater facility for reading it. At the eye. end
of the telescope a square piece of glass is let in opposite the cross-hairs
for the purpose of illuminating the wires by means of a candle or lamp
underground or at night, and when not in use there is a brass slide
which effectually shuts out all light in the daytime. There is also a
micrometical arrangement in the eye end of the telescope to be employed
as a distance measurer. A lever clamp is attached to the vertical circle
which is much more effective than a clamp screw which is ordinarily
attached. Special station staffs will be provided for this instrument for
surface work, and lamps for underground work. The arrangement of
the instrument or angleometer can be effectively applied to all surveying
instruments from a transit to a conimon miner's dial.
SPECIFICATION in pursuance of the conditions of the Letters Patent, a
filed by the said Henry Davis Hoskold and John Emanuel Winspear
in the Great Seal Patent Office on the 8th November 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
DAVIS HOSKOLD, of Cinderford, in the County of Gloucester, Mining
and Civil Engineer, and JOHN EMANUAL WINSPEAR, of Kingston-upon-

page_text: Hull, in the County of York, Mathematical Instrument Maker, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of May, in the year of
Our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give.
and grant unto us, the said Henry Davis Hoskold and John Emanuel
Winspear, Her special licence that we, the said Henry Davis Hoskold
and John Emanuel Winspear, our exccutors, administrators, and assigns,
or such others as we, the said Henry Davis Hoskold and John Emanuel
Winspear, our executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
“IMPROVEMENTS IN SURVEYING INSTRUMENTS," upon the condition (amongst
others) that we, the said Henry Davis Hoskold and John Emanuel
Winspear, or one of us, our executors or administrators, by an instru-
ment in writing under our, or one of our, or their, or one of their
hands and seals, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be per-
formed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that the said Henry Davis Hoskold and John
Emanuel Winspear, do hereby declare the nature of our said Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement thereof,
reference being had to the Drawings hereunto annexed, that is to
say :-
This Invention relates to a new surveying instrument for measuring
angles in field and underground work.
The instrument is made with a divided limb, and is mounted with a
telescope which revolves, and thus becomes a transit instrument of
great power; its particular form renders it well adapted to be used as a
zenith telescope, and also for connecting underground surveys to those
on the surface directly by means of the telescope without magnetic
bearings. In this instrument the length of telescope does not regulate

page_text: •
the height, as a small instrument of this class may be made to carry a
telescope of equal length and power with some of the larger instruments
of the old type. The horizontal axis carrying the telescope and vertical
circle is mounted close down on low bearings on the upper vernier plate.
.These bearings, axis, and all other internal arrangements are covered up
by a magnetic compass box, which also is of the same diameter as the
graduated limb. The needle carries a silver floating circle with a vernier
at each end, and it rests in a recess cut in the edge of the inner divided
circle; it is thus preventing from rocking or vibrating unduly. The
telescope is fixed in a stout cylindrical ring at one end of the horizontal
axis, and made to rotate in it vertically for the purpose of "collimation."
The vertical circle is constructed with a conical limb, and the gradua-
tions are put on the edge thereof instead of, as usual, against the side of
it; there is consequently greater facility for reading it. At-the cye end
of the telescope a square piece of glass is let in opposite the cross hairs
for the purpose of illuminating the wires by means of a candle or lamp
when used underground or at night, and when not in use there is a brass
slide which effectually sluts out all light-in-the-daytime. There-is-also-
⚫a micrometrical arrangement in the eye end of the telescope to be
employed as a distance measurer. A lever clamp is attached to the
vertical circle, which is much more effective than the clamp screw
ordinarily attached. Special station staffs will be provided for this
instrument for surface work, and lamps for underground work. The
arrangement of the instrument or angleometer can be effectively applied
to all surveying instruments from a transit to a common miner's dial.
The manner of carrying our Invention into effect will be understood
by referring to the accompanying Drawings and to the following
description thereof:-
The instrument is made with a divided horizontal circle A, as seen in
the sectional view, Figure 1, and elevation, Figure 2, and is mounted
with a telescope shewn at B, which revolves vertically, and thus becomes
a transit or universal instrument of great power and capability. Its
particular form renders it well adapted for general use as well as a zenith
telescope or sector, and also for connecting underground surveys to those
on the surface directly by sighting down a shaft with the telescope
'without the aid of magnetic bearings. In this instrument the length of
telescope does not regulate the general height, as a comparatively small
instrument of this class may be made to carry a telescope of far greater

page_text: length and power than is or can be applied to portable instruments
of the old type having divided limbs of the same diameter, without
rendering them too unwieldy. The horizontal axis C, Figure 1, carrying
the telescope B and the vertical circle D, is mounted close down on low
bearings, represented at. a, a, a³, a', Figure 1, and also at a", a", and
a, a, Figures 3 and 4, on the upper vernier plate b, b. These
bearings, axis, and all other arrangements exhibited in the sectional
clevation, Figure 1, are covered up by a magnetic compass box, as
illustrated in the elevation, Figure 2, which compass box is of the same
diameter as the graduated limb A. The needle E, shown in the general
plan, Figure 5, carries a light silver circle with a vernier at each end, or
a vernier only at each end of the said needle, and it rests in a recess cut
in the edge of the inner divided circle at c, c'. It is thus prevented
from rocking or vibrating unduly, and an accurate reading of the
graduated circle is quicker ensured. The telescope is fixed in a short
cylindrical ring at one end of the horizontal axis, as shown at F,
Figures 1, 2, and 5, and made to rotate in it vertically, as shewn in the
part sectional plan of the said telescope, Figure 6, for the purpose of
"collimation." The vertical circle D is constructed with a conical edge,
and the graduations are put on it instead of, as usual, against the side
thereof. There is consequently greater facility for reading it by means
of the lenses 1 and 2, Figure 5. At the eye end of the telescope a
square piece of glass is let into it nearly opposite the cross collimating
hairs, as at d, and a reflector placed inside the telescope in such a
manner that the cross hairs become illuminated when the light of a
candle or lamp is made to throw its rays against the glazed opening
before referred to. This contrivance is for the purpose of facilitating
observations underground or on the surface at night. When it is not so
employed there is a brass slide which effectually shuts out all light in
the daytime by turning a small lever 3, Figure 5. The general arrange-
ment of the vertical circle D is exhibited in the sectional elevation,
Figure 1, and also in the elevation and plan, Figures 2 and 5; it
revolves with the telescope and axis. The vernier's clamp and tangent
screw is also shown in the Figures before referred to, and is dead fitted,
5 and the collar thereof screwed to the upper vernier plate b, b¹. Instead
of having a clamping screw with a large milled head a lever is con-
structed with the screw in one piece, which gives greater effect. The
general arrangement of it with verniers and spirit bubble is shown in
Figure 7. The microscopes 1, 2, 4, and 5, Figure 5, are constructed

page_text: with an opening in their sides closed with glass, and a reflector placed
inside. When therefore a light is brought so that its rays fall upon the
glass they are conveyed to the graduations upon the circle, thus enabling
an observer to have a clear and distinct view of them. The verniers to
the horizontal and vertical circles are constructed to slide in a groove in
the plane of the graduated limbs, and by turning a small screw attached
to each of them they may be adjusted as near to or as far away as it
may be necessary or convenient for the delicate divisions on the said
verniers to be brought in contact with those on the principal circles.
The principal object of this is to bring the plates close together or
parallel to every point in the circle around which they move, and to
enable-an observer to read off more accurately.
A micrometrical arrangement is also constructed to accompany the
instrument, the purpose of which being to obtain distances without
direct measurement, also for the purpose of measuring very small angles
such as cannot be obtained from the divisions upon the circles of the
instrument. Thus, if the micrometer head is divided into 110 parts,
with a screw attached of 25 threads per inch, each-division--upon-the..
drum would be equal to half a second of arc. Therefore by using the
micrometrical apparatus in connection with the divided circles of the
angleometer angles in the field can be measured with as much accuracy
and delicacy as by instruments of the old type of very much larger
dimensions, which from their ponderous and cumbrous nature are not
sufficiently portable to be taken from station to station in performing
general work.
As the telescope is placed at the side instead of at the centre of the
instrument, it would seem that every angle taken with it in the field
(after the first one) would be in error, and in amount due to the
distance from the centre of the instrument to that of the optical axis of
the telescope and the length of the line under survey, but it is intended
to employ specially constructed station poles, so as to cause the line of
sight of the telescope to be parallel to a line running through the centro
of the instrument. This is effected by having an observing pole with
double points removed from each other a distance equal to that from the
centre of the instrument to that of the optical axis of the telescope, and
.constantly sighting at one point to the pole, while the other is held over
or is in contact with the station peg. For underground work special
lamps of a similar character are provided.

page_text: Referring again to the bearings a, a, a', a', and a", a¹¹, a", a¹¹¹¸
Figures 1, 3, and 4, it is intended that they shall be lined with either
agate or glass for the purpose of destroying any undue amount of
friction of the parts.
Having thus fully described and ascertained the nature of our said
Invention and the manner of carrying the same into effect, we declare
that we claim, the new and improved arrangement of apparatus for
measuring angles and taking magnetic bearings, substantially in the
manner hercin-before fully set forth and represented in Figures 1, 2, 3,
4, 5, 6, and 7 of the accompanying Drawings; also the application of
the apparatus as herein-before described to miners' dials, as illustrated
in Figure 8, or to any other kind of surveying instrument in which
such apparatus is applicable.
In witness whereof, I, the said Henry Davis Hoskold and John
Emanuel Winspear, have hereunto set our hands and seals,
this Sixth day of November, One thousand cight hundred and
seventy-onc.
H. D. HOSKOLD. (L.S.)
J. E. WINSPEAR. (L.S.)