IMPROVEMENTS IN COMPASSES OR APPARATUS FOR REGISTERING THE COURSE STEERED BY A SHIP DURING ANY GIVEN PERIOD
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by William Arthur at the Office of
the Commissioners of Patents, with his Petition, on the 24th September
1864.
I, WILLIAM ARTHUR, of Atherington, in the County of Devon, Commander
in the Royal Navy, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN COMPASSES OR APPARATUS FOR REGISTERING THE COURSE
STEERED BY A SHIP DURING ANY GIVEN PERIOD," to be as follows:-
The object of my Invention is to make a compass register the courses
steered by a vessel during any given period.
For this purpose I suspend a cylinder fitted vertically in a framing on a
shaft, needle, or axis at both ends, or the cylinder may be supported partly on
a point or pivot at bottom and partly by a cord at top, rollers being added to
keep the cylinder steady, or it may be partly supported by rollers both at top
and bottom, or by being partly immersed in mercury or other suitable liquid;
the shaft of the cylinder carries one or more permanent or electro-magnets; a
sheet of paper is wrapped round the cylinder and is secured thereto; this paper
is marked with division lines, the distance of which from each other is regu-
lated according to the speed at which a pencil is caused, to travel; this pencil
is made to descend by clockwork, by which the speed at which it travels is
determined. The pencil is held in a socket in a frame, and is caused to strike
against or come in contact with the paper on the cylinder at regular intervals
by the projections on a ribbed roller, which is made to revolve by the clockwork
coming against a projection on one end of an arm forming part of the frame;

page_text: at other times the pencil is kept from contact with the paper by a spring, or the
pencil may be brought in contact with the paper in any other convenient manner.
The frame carrying the pencil is mounted on a threaded rod caused to rotate
by the clockwork, whereby the pencil is made to descend gradually from top
to bottom of the cylinder. Instead of being mounted on a rod, the pencil may
be secured to a band passing over rollers, one of which is caused to rotate by
the clockwork; sometimes I communicate the position of the needle of the com-
pass at intervals by electricity to a cylinder or roller, or tape, or band of paper
placed in the cabin or other part required, and I prefer to accomplish this as
follows: I fit to the compass a ring with an inner flange made to rise and
fall at intervals by clockwork; in its downward movement the flange comes in
contact with one end of a bar balanced on a fulcrum and free to turn with a
magnet placed above it; the flange presses down one end of the bar until it
comes in contact with one of a series of wires or points arranged round a ring
placed below; each of the wires or points is in connection with a separate wire
leading each to an electro-magnet; as soon as contact is made the electro-mag-
net attracts its armature, which forms part of a lever furnished with a point or
pencil to mark upon the paper in the cabin; the paper may be caused to move
by clockwork or by another electro-magnet. Instead of marking on the paper
with a point or pencil, I sometimes employ paper prepared for photographic
purposes, and allow the course of the vessel to be registered thereon by the
action of light admitted through an aperture.