IMPROVEMENTS IN SHIPS' COMPASSES
Year: 1868

page_text: LETTERS PATENT to Paul Cameron, of Glasgow, in the County of
Lanark, North Britain, for the Invention of "IMPROVEMENTS IN SHIPS'
COMPASSES."
Sealed the 20th November 1868, and dated the 25th May 1868.
PROVISIONAL SPECIFICATION left by the said Paul Cameron at the
Office of the Commissioners of Patents, with his Petition, on the
25th May 1868.
I, PAUL CAMERON, of Glasgow, in the County of Lanark, North
Britain, do hereby declare the nature of the said Invention of "Ix-
PROVEMENTS IN SHIPS' COMPASSES," to be as follows, that is to say:-
This Invention, which relates to an improved compass for indicating
a ship's course independent of celestial or terrestrial observations, consists
in obtaining a strong directive power by employing a sheet or disc of
steel or iron magnetised according to the reed or fibre of said steel or
iron. The disc or sheet is suspended between centres, and is also
arranged that it may rest on pivots horizontally, in which position it
at once indicates the dip when passing the magnetic line, and when
moved to east or west it assumes an upright position. The compass
card being attached, the true bearings are indicated. Surrounding the

page_text: instrument there is a moveable circle or card marked with the degrees
and points of the compass, which when moved to these cardinal points
indicate the ship's true course. The outer bowl of the compass in place
of being suspended as hitherto is hung by springs, so that the instrument
may be less affected by the vibrations and tremor of the ship.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Paul Cameron in the Great Seal Patent Office
on the 25th November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PAUL
CAMERON, of Glasgow, in the County of Lanark, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of May, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Paul Cameron, Her special license that I,
the said Paul Cameron, my executors, administrators, and assigns, or
such others as I, the said Paul Cameron, executors, administrators,
or assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN SHIPS' COMPASSES," upon
the condition (amongst others) that I, the said Paul Cameron, by
an instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Paul Cameron, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say:-

page_text: My said Invention which relates to an improved compass for indicating
a ship's course independent of celestial or terrestrial observations, con-
sists in obtaining a strong directive power, by employing a sheet or disc
of steel or iron magnetised according to the reed or fibre of said steel
or iron. The disc or sheet is suspended between centres, and is also
arranged that it may rest on pivots horizontally, in which position it at
once indicates the dip when passing transverse to the magnetic line,
and when moved relatively to east or west it assumes an upright position.
The compass card being attached, the true bearings are indicated.
Surrounding the instrument there is a moveable circle or card marked
with the degrees and points of the compass, which when moved to the
cardinal points indicates the ship's true course. The outer bowl of the
compass in place of being suspended as hitherto is hung by springs,
so that the instrument may be less affected by the vibrations and tremor
of the ship.
And in order that my said Invention may be properly understood I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used, or practically carried
into effect, reference being had for the sake of more complete elucidation
to the letters and figures upon the explanatory Sheet of Drawings which
I have hereunto appended, that is to say :-
Figure 1 is a vertical section on the line A, B, of the plan; Figure 2
and Figure 3 is a section on the line C, D, Figure 2; on these Figures
similar parts are indicated by corresponding letters of reference.
The compass shown in Figures 1, 2, and 3 may be described as a disc-
dipping compass, whereby the true bearings of the ship's course may be
found independent of celestail or terrestrial observations. To effect this
a sheet or disc of steel a is employed suspended in a horizontal direction
on pivots b, b, this sheet or disc is magnetised north and south, so that
the reed or fibre of the steel is parallel with the poles; by this means
the magnetic atoms in the disc arrange themselves in a more perfect
way for receiving the magnetic influences or currents. The pivots b, b,
are supported in suitable bearings c fixed to a copper ring d, fitted
inside of the bowl e. The bowl e is suspended by a rim or flanched
ring f, which is fixed round its mouth and rests upon an india-rubber
tube g, which is carried in the gimbal ring h; by this means an elastic
cushion is provided for the compass, and prevents its undue disturbance
from concussion, or the rolling or pitching of the ship. i, i, Figures 2

page_text: and 3, are pivots on which the gimbal ring h swings inside the gimbal
ring j, which is swung on pivots k fixed in the moveable graduated
ring 1, which is supported on the stand m. The bowl e is weighted with
lead, as shown at n, Figures 1 and 2, so as to make the gimbal rings
answer any change of position promptly, and thus maintain the axis or
pivots b, b, in a horizontal position; a semicircular graduated index o is
placed over the magnetic disc a to indicate the angle or dip.
The action and method of observing with the compass is as
follows: The compass is placed in the cabin or other convenient part
of the ship with the indicated points C, D, in the line of the longitudinal
axis of the ship if the cardinal points N and S marked on the graduated
ring, correspond with the points C, D, and the ship is not sailing on
the magnetic meridian; the disc a will be deflected in the manner shown
on Figure 1 by the magnetic currents of the earth, and in the case of
iron ships would be assisted by the disturbing influences due to the
position of the magnetic poles in the hull. In order to find the true
course of the ship the graduated ring is turned slowly round until the
disc a assumes an upright or perpendicular position, in which position
it is evident the axis of the disc a will be parallel with the magnetic
meridian, and indicate the north, south, east, and west points. The
observer now notes the point on the graduated circle which is cut by
the mark C, thus giving the true course in which the ship is sailing. If
it is required to find the deviation of the steering compasses from the
magnetic north due to the disturbing influence in the ship's hull, this is
done by turning the compass slowly round until the disc a assumes the
greatest dip, which is indicated by the semicircular index o, and thus
gives the correct deviation as required. The disc a is adjusted or
balanced for correct indication by a small brass ball. P, which
may be
moved upon a screw fitted in a hole cut in the centre of the disc,
as shown.
Figure 4 is a vertical section on the line A, B, on Figure 5, which
is a plan of a steering compass. In this arrangement the disc a
is held in a strap q by a pinching screw ", and is permanently situated
in a vertical position, supported by the pivots b, b, carried in suitable
bearings in the bracket c, and the screw c¹. The indicating card 8 is
fixed in a horizontal position on the disc a, as shown. The bowl e is
suspended by metallic springs g from the gimbal ring h, which is swung
in the manner herein-before described in reference to Figures 1, 2, and 3.

page_text: The action of this compass is similar to the ordinary needle steering
compass in present use.
Figure 6 shows another arrangement of steering compass. In this case
the disc a is cut into segments, and placed at an angle under the indi-
cating card 8, which turns upon a pivot b, carried in the tubular bracket c,
in the bottom of which a spring f is fitted to form a cushion for the
pivot b. The other parts of this modification are the same as herein-
before described in reference to the preceding Figures.
Having now described the nature of my said Invention, and the
manner in or under which the same is or may be used or practically
carried into effect, I would observe in conclusion that what I consider
novel and original and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,-
First. The general arrangement and construction of true course indi-
cating compasses, as herein-before described and shown in Figures 1,
2, and 3 of the accompanying Drawings, or any mere modification
thercof.
Second. The application to ships' compasses of rolled and tempered
steel discs, magnetised north and south in the direction of the reed or
fibre of the steel, whereby a stronger directive power is obtained than
by the use of needles, as hercin-before described and shown in the
accompanying Drawings.
Third. The suspending of the bowls of ships' compasses by metallic
springs, as herein-before described and shown at g, Figures 4, 5, and 6
of the accompanying Drawings, or any mere modification thereof.
Fourth. The method of cushioning the bowls of ships' compasses by
resting them upon india-rubber tubes, as shown at g, Figures 1 and 3
of the accompanying Drawings, and herein-before described, or any mere
modification thereof.
In witness whereof, I, the said Paul Cameron have hereunto set my
hand and seal, this Twenty-third day of November, One thousand
eight hundred and sixty-eight.
PAUL CAMERON. (L.S.)