An Improved Instrument for Measuring and Indicating Horizontal and Vertical Angles, and for Plotting the same on to Paper or other suitable Material.
Year: 1890

page_text: Date of Application, 22nd Nov., 1890
Complete Specification Left, 18th Aug., 1891--Accepted, 7th Nov.,
1891
PROVISIONAL SPECIFICATION.
An Improved Instrument for Measuring and Indicating Horizontal
and Vertical Angles, and for Plotting the same on to Paper or
other suitable Material.
ARTHUR HERBERT CLEVELAND KENNEY HERBERT, Lieut. Northamptonshire
Regiment, Instructor in Military Topography, Royal Military College, Yorktown,
Surrey, and ALBERT FARRAR GATLIFF Captain, Royal Marine Light Infantry,
Instructor in Fortification, Royal Military College, Yorktown, Surrey, do hereby
declare the nature of this invention to be as follows:-
The instrument consists of a ring graduated to read degrees from 0° to 360°.
Inside this ring is a fitting with parallel runners to act as a carriage for a box or
boxes containing a magnetic compass and a spirit level. A meridian line is drawn
across the centre of the compass box parallel to the side edges of the box and a
line is drawn round the glass of the level to indicate the centre. The dimensions
of the box & the arrangement of the carriage are such that either the centre of the
magnetic needle or the centre of the level can be alternately set in the centre of
the graduated ring. The whole of this portion of the instrument as described
above is so constructed that it can be revolved truly on a suitable centre or base.
To this base or centre is attached a radial arm or rule with bevelled edges.
Suitable scales are marked on the edges and on the face of this rule.. On the end
of the rule nearest the ring is fixed an arm to which is attached a sight containing
a right angled prism or plane mirror at an angle of 45°. The arm is of such length
that the centre of the prism or mirror will be in a position exactly over the centre
of the graduated ring. If desired a plain sight without the prism or mirror
attachment can be employed. Also the arm carrying the sight can he made with
a sliding adjustment so that the arm can be adjusted to any desired length. For
convenience sake the arm is hinged so that the sight can be folded over to make
the instrument more compact when not in use. A lens of suitable form and focus is
fitted to the arm in a position exactly over that portion of the graduated scale on the
ring which happens to be opposite to the indicator which is fixed to the end of the
rule opposite the edge of the graduated ring. The lens can be fitted, if necessary,
with an adjustment to set it to the exact focus. On the other end of the rule
another hinged sight is fixed. The line through these sights is parallel to the
edges of the rule. The instrument is made of metal or wood or a combination of
metal and wood or any other suitable material. The instrument is of any size but
preferably of a size suitable to hold in the hand.
Dated this Seventeenth day of November 1890.
COMPLETE SPECIFICATION.
An Improved Instrument for Measuring and Indicating Horizontal
and Vertical Angles, and for Plotting the same on to Paper or
other suitable Material.
ARTHUR HERBERT CLEVELAND KENNEY HERBERT, Lieut. Northamptonshire
Regt., Instructor in Military Topography, Royal Military College, Yorktown,
Surrey, and ALBERT FARRAR GATLIFF, Captain, Royal Marine Light Infantry,
Instructor in Fortification, Royal Military College, Yorktown, Surrey, do hereby
declare the nature of this invention and in what manner the same is to be.

page_text: Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:
1. The combination of a magnetic needle and spirit level with a divided circle
and plotting arm attachment substantially as described.
2. The use of either a prism or mirror to see from the eye end when the magnetic
needle is in. the meridian and the spirit bubble central.
3. The combination of sights with the plotting arm, and compass, and level
substantially as described.
Dated this Fifteenth day of August 1891
H. W. L. STEWARD,
Agent for Applicants.