Improvement in Magnetic Compasses for Military and other Purposes, more particularly for use at Night.
Year: 1897

page_text: Date of Application, 14th Apr., 1897
Complete Specification Left, 3rd Feb., 1898-Accepted, 2nd Apr., 1898
Improvement in Magnetic Compasses for Military and other
Purposes, more particularly for use at Night.
THOMAS WATLING SHORT & WILLIAM JAMES MASON, trading as Short and Mason,
Scientific Instrument Makers, 40, Hatton Garden, Holborn, E.C., do hereby
declare the nature of this invention to be as follows:
The invention consists of a mechanical arrangement by which a given magnetic
course can be set exactly to a single degree without the aid of light in any way.
The method employed is an endless screw each turn of which has a given value
relatively to the degrees of the compass dial, and upon the angle or direction of
the course required to be set, depends the number of turns to be given to the endless
screw. Provision is made for returning the indicator to zero after a course has
been set & before setting a fresh one.
0 A
L.
100
THOMAS WATLING SHORT.
WILLIAM JAMES MASON.
Improvement in Magnetic Compasses for Military and other
Purposes, more particularly for use at Night.
THOMAS WATLING SHORT, WILLIAM JAMES MASON, trading as Short and Mason,
40, Hatton Garden, Scientific Instrument Makers, 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: -
can be
The invention consists of a mechanical arrangement by which a given magnetic
course may be set accurately, to a single degree without the aid of light in any
way. The method employed is an endless screw or pinion working into a toothed
wheel, each turn of which has a known value, and the number of
turns of the
the angle required.
screw or pinion is governed by
The gearing of the screw or pinion into the toothed wheel
arranged to give different speeds or rates so that an entire turn may move
the body of the compass over 1°, 2° 5° 10° or any number of degrees desired.
The inner part of the compass case is made to rotate by turning the milled edge
ring A. This ring should be turned from left to right until it reaches the stop B.
The zero or starting point from which the angle of direction is to be counted by
the use of the screw and gearing. This milled edge ring is fitted with a glass,
covering the magnetic compass, and upon this glass a black line of direction is

page_text: painted, and when turned to the stop coincides with the zero point. A handle or
lever is attached to the screw or pinion which being turned from a given point the
number of turns can be counted and the true magnetic course set without the aid of
light. The inside of the lid of the compass case, as well as the surface of the
compass dial are covered with a luminous substance & by means of this luminosity
the black line of direction on the glass as well as the line of direction in the lid
are visible, and the magnetic course can be followed. The position of the screw
or pinion may be as shown in Fig. I in the drawing annexed, where it is attached
near the pendant bow, and in a vertical position, or it may be attached as in
Fig. III horizontally, or it may be attached at the side or other part of the
circumference of the compass either vertically or horizontally.
DESCRIPTION OF THE DRAWINGS.
C is the outer case of the compass in which an inner case E is revolved by means
of the wheel & pinion gearing in Fig. I and by the endless screw in Fig. III.
This inner case E carries by a tight fitting the milled edge ring A which revolves
with it when actuated by the mechanism but can be turned independently by the
fingers. H is the glass upon which the line of direction K is painted.
Fig. I shows the compass open. The milled edge ring A turned to meet the
stop B setting the course line K to zero. Lis the handle which being turned a
given number of times places the course line K over any required degree of the
compass.
Fig. II shows the compass in section L the handle carries a pinion M gearing
into the toothed wheel N, and its pinion O again gears into the toothed wheel
attached to the bottom of the inner case E before mentioned.
Fig. III shows the mode of obtaining the same motion of the inner case E by
means of an endless screw gearing into a toothing cut on the outside circum-
ference of the case E itself.
Having now particularly described & ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
-
A magnetic compass which can be set to any given angles or number of degrees
without the aid of light, by means of an endless screw or pinion working into
toothed wheel gearing substantially as described.
Dated this Second day of February 1898.
THOMAS WATLING SHORT.
WILLIAM JAMES MASON.