Improvements in Magnetic Compasses of the kind known as the "Trough" Compass.
Year: 1894

page_text: Date of Application, 16th Feb., 1894
Complete Specification Left, 15th Nov., 1894-Accepted, 5th Jan., 1895
PROVISIONAL SPECIFICATION.
Improvements in Magnetic Compasses of the kind known as the
"Trough" Compass.
PERCY JOHN DIXON Captain 2nd (South) Middlesex Volunteer Rifles Beaufort
House Walham Green London S. W. do hereby declare the nature of this invention
to be as follows:-
:-
The application to a magnetic trough compass, of a transparent bottom and the
widening of the box to admit of an improved dial and consists of a magnetic
compass the body or case of which is of suitable metal oblong shaped the top and
bottom being of glass, talc, horn or other similar transparent substance enabling the
details of a map to be seen through it-or so that on a dark night the points of the
compass may be distinctly seen by the diffused light of the clouds upon its being
held above the head-or when such are available a transparent map placed over a
luminous painted surface may be seen through the compass on its being placed
thereon and the points of the compass read at the same time.
The points of the compass are painted boldly on the inner surface of the bottom
and also a well defined "North and South line" the magnetic needle being flat and
conspicious by its width.
Dated this 31st day of March 1894.
PERCY DIXON,
Capt.
Improvements in Magnetic Compasses of the kind known as the
"Trough" Compass.
PERCY JOHN DIXON Captain 2nd (South) Middlesex Rifles Beaufort House
Walham Green London S.W. do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The application to magnetic compasses of the trough or oblong box pattern of a
transparent base as well as top that will allow details to be seen through it and so
facilitate operations by night when used with a transparent map over a luminous
painted surface or held over the head against the sky or for illumination by diffused
light above, as well as for general use with maps by day. Also the widening of
the case, box or body of the compass to admit of an improved dial being formed by
means of the distinctive markings on the transparent base to show at once N. & S.
and the other cardinal points. A magnetic compass having such improvements
applied to it and which is herewith figured is constructed with the case, box, or
body A. A A"A" preferably of metal, although other substances can be used
for it, while the base B could be of glass, tale, horn, or other similar transparent
substance that would enable lines, names, and details to be seen through it. The
pivot on which the magnetic needle works being fastened by pins, collets, or cement to
or through the transparent base, while the width of the case or box is such that the
needle can
move about 40 degrees east or west of north, the amount of such
movement being shewn by the divided arc. The combination of the transparent
PQ.7 1

page_text: base (dial) and the rectangular sides of the compass box facilitates the drawing of
a line to show the magnetic variation for any locality which can be expeditiously
done by the following method:-Supposing one has an ordnance map or other
drawn true north and the magnetic variation is say 17 degrees west, place the
compass with N. pointing to top of map & the centre on which the needle is
pivoted on the right or E. edge of map or any line parallel to it, turn the compass
to the left until the edge or line on map cuts the 17th degree marked on dial cast
of north. If now a line is drawn along the left or west side of the box as illustrated
by pencil C. a magnetic line (17° W.) will be shewn for that locality. The dial
being transparent the names of the villages, directions of roads &c. can be seen
through it and the moving of compass is thus avoided, when once settled. The
mounts or lugs D. D' at each end of the oblong case euable the compass to be
pinned to a board and carried about without fear of loss, and at the same time
effecting a saving of time in adjustment.
While I am aware that compasses of the ordinary circular pattern already exist
with glass or transparent bottoms and I therefore disclaim any improvement thereto,
I know of no such instrument as a trough pattern compass having a transparent
base & dial and the improvement substantially as now figured and described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
1. The application of a combined transparent base & dial to magnetic compasses
known as the trough pattern with cardinal points or degrees or both cardinal
points and degrees painted on, or affixed thereto substantially as figured and
described.
2. The application of fittings or lugs to the sides or ends of compass case for
inserting pins or wire, string, or other such like material to secure it to a board for
the purpose herein set forth.
3. A transparent trough compass substantially as figured & described.
Dated this Fifteenth day of November 1894.
PERCY J. DIXON,
Captain, 2nd South Middlesex Rifles.