An Improved Apparatus for Measuring Vertical and Horizontal Angles for Nautical, Surveying, and like Purposes.
Year: 1897

page_text: An Improved Apparatus for Measuring Vertical and Horizontal
Angles for Nautical, Surveying, and like Purposes.
1, EDWARD NORMAN SENNETT, of 1, Florence Terrace, Stamshaw, Portsmouth,
Seaman in Royal Navy, do hereby declare the rature of this invention to be as
follows:-
My invention relates to an improved apparatus for measuring vertical and hori
zontal angles. In its complete form, it consists of a semi-circular base having the
semi-circular edge suitably graduated, the graduations reading direct if the instru-
ment is used for direct vision, or doubly if it is used by reflection. Extending
from side to side of the diameter of the base is an arch. At a point immediately
over the centre from which is struck the graduated arc of the base is pivotted one
end of a flat are, whose lower end can travel along a semi-circular platform some-
what above the graduated edge of the base. This vertical area is graduated from
zero upwards and from zero downwards or in any other suitable manner, and is
slotted from near one end to near the other end, and in this slot is a runner
carrying a pointer or pointers for indicating the angles on the arc. To the runner
is also attached one end of a tolescope, free to move vertically from a pivotting
point supported above the centre from which is struck the graduated edge of the
Dase, The pointer or pointers may be moved up and down by cords, chains, racks,
pinions, worms, or otherwise. Verniers and magnifying glasses may be used in
connection with the pointers of the vertical are and also with the lower end of
it which travels above the graduated edge of the base.
Pivoted to the centre of the diameter of the semi-circular base is an arm
extending to the graduated edge, and movable between it and the platform on
which travels the lower end of the vertical arc. The outer end of the arm is pro-
vided with a vernier and magnifying glass, and vertically over the centre and
attached to and moving with the arm is the index glass with its reflecting surface
towards the graduated edge of the base. At one end of the diameter of the base
is a telescope the axis of which points towards the centre of the graduated edge of
the base and cutting the axis is the horizon glass attached to the base, the re-
flecting half of the glass being towards the reflecting face of the index glass. The
position of the horizon glass is parallel with the index arm when the latter is at
zero. An adjustable sight may be provided for attaching to the diameter of the
base for taking low heights directly. Colored screens may be used where necessary
when reflection is employed. More than one vertical arc can be provided and
lower end of it or them can be adjusted by rack pinion, worm or otherwise, as also
may be the end of the index arm. A handle may be provided below the back of
the base for holding the instrument during use, and the handle may be hollowed
out to contain materials for silvering glass. The apparatus may be modified by

page_text: omitting the reflecting parts or by omitting those for direct vision. Provision
may be made for levelling the apparatus and a compass may be attached. Fine
adjustments may be provided for by tangent screws wherever necessary.
Dated this 10th day of December 1897.
HUGHES & YOUNG,
23, Coleman Street, London, E.C., Agenta for Applicant.
An Improved Apparatus for Measuring Vertical and Horizontal
Angles for Nautical, Surveying, and like Purposes.
I, EDWARD NORMAN SENNETT, of 1, Florence Terrace, Stamshaw, Portsmouth,
Seaman in Royal Navy, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement;-
My invention relates to an improved apparatus for measuring vertical and
horizontal angles for nautical, surveying and like purposes, and in putting it
into practice I proceed in or in about the following manner making reference to the
accompanying drawings of which Fig. 1 is a part sectional plan. Fig. 2 is a part
sectional side view, Fig. 3 is a back view with most of the details omitted.
Similar letters indicate the similar parts in all the figures. I provide a semi-
circular base a having the semi-circular edge suitable graduated, the graduations
reading direct if the instrument is used for direct vision, or doubly if it is to be
used by reflection. Extending from side to side of the diameter of the base is
an arch b. At a point immediately over the centre from which is struck the
graduated are of the base is pivotted one end of a flat arc c whose lower end can
travel along a semi-circular platform d somewhat above the graduated edge of
the base. The are c is graduated from zero upwards and from zero downwards
or in any other suitable manner and is slotted at e from near one end to near the
other end and in this slot is a runner carrying a pointer for pointers for indicating
the angles on c.
To the runner and free to move therewith is attached an end
of a teleslope g which can be turned vertically on pivois h supported above the
centre from which is struck the graduated arc of the base. The pointer or pointers
and the telescope g can be moved up or down by cords, chains, racks, pinions,
worms or otherwise or by a toothed quadrant or section operated by a pinion j.
Verniers and magnifying glasses may be used in connection with the pointer f, also
with the lower end of the arc c which travels along d.
Pivotted to the centre of the diameter of the semi-circular base a is an arm &
extending to the graduated edge and moveable between it and the platform d.
The outer end of is provided with a vernier and magnifying glass and vertically
over the centre and attached to and moving with the arm is the index glass
with its reflecting surface towards the graduated edge of a. At one end of the
diameter of a is a telescope m the axis of which points towards the centre of the
graduated edge of a and cuts the horizon glass attached to a, the reflecting half
of n being of course towards. The position of n is parallel with & when the latter
is at zero.
An adjustable sight may be provided for attaching to the diameter
of a for taking low attitudes directly. More than one are c or one telescope y may
be provided and in any case the lower end or ends of it or them may be adjusted
by rack, pinion, worm or otherwise, as may also be the end of k.
A handle of any suitable kind may be provided at the back of a or elsewhere by
which the instrument can be held during use. This handle may be tubular and
contain materials for silvering glass. The handle might also or alternatively be

page_text: made to contain an electric lamp and battery for use with the instrument when
other light is not available.
The instrument may be modified by omitting the reflecting parts or by omitting
those for direct vision. Provision may be made for levelling the apparatus and a
compass may be attached. Tangent screws or other provision may be made for
fine adjustments of any of the parts of the instrument. The instrument may be
used on a tripod if required.
I do not confine myself to the precise shapes, relative proportions or dispositions
of parts shown in the drawings or described in the above specification as any or
all of them may be varied to a considerable extent without departing from the
essential features.
Having now particularly described and ascertained the nature of my said
invention. and in what manner the same is to be performed I declare that what I
claim is;-
=
1. An improved apparatus for measuring vertical and horizontal angles for
nautical, surveying and like purposes the said apparatus consisting essentially of
(«) A semi-circular base having a graduated edge on which is free to travel one
end of an index arm having its centre at the centre of the diameter of the base
and bearing an index glass. (b) A graduated semi-circular platform above the
base and its index arm. (c) An arch extending from one and of the diameter of
the base to the other. (2) A slotted and graduated arc one end of which turns on
a point in the above mentioned arch the said point being situated above the centre
of the base, the other and being free to travel along the above mentioned platform.
(c) A telescope moveable on pivots in supports rotatable on a point above the
centre of the diameter of the base, the elevation or depression of the telescope being
indicated by a runner working along the above mentioned slotted arc. (f) A
telescope attached to one end of the diameter of the base. (g) A horizon glass
attached to the base. (h) Verniers and magnifying glasses to facilitate the reading
of the graduation. (i) Means for elevating and depressing the telescope and for
making fine movements of the index arm and the slotted are, the whole substantially
as described in the above specification and exemplified in the accompanying
drawings.
2. A modification of the apparatus which is the subject matter of the above
Claim 1 whereby more than one telescope is provided for use with the slotted arc,
substantially as described in the above specification.
3. Modifications of the apparatus which are the subject matter of the above
Claims 1 and 2, whereby more than one slotted arc is employed, substantially as
described in the above specification.
4. A modification of the apparatus which is the subject matter of the above
Clains 12 and 3 whereby the parts for taking readings by reflection are omitted
and those for direct reading retained, substantially as described in the above specifi-
cation.
5. A modification of the apparatus which is the subject matter of the above
Claims 12 and 3 whereby the parts for taking readings by direct observation are
omitted and those for readings by reflection retained, substantially as described in
the above specification.
6. The combination of parts substantially as described in the above specification
and exemplified in the accompanying drawings and forming improved apparatus
for measuring vertical and horizontal angles for nautical surveying and like
purposes.
Dated this 1st day of October 1898
HUGHES & YOUNG,
23, Coleman Street, E.C., Agents.