IMPROVEMENTS IN THE MARINER'S COMPASS
Year: 1854

page_text: LETTERS PATENT to John Sands, of 11, Austin Friars, in the City of
London, for the Invention of "IMPROVEMENTS IN THE MARINER'S COMPASS."
- A communication from William Graham, of Australia, Master
. Mariner.
Sealed the 26th January 1855, and dated the 30th November 1854.
PROVISIONAL SPECIFICATION left by the said John Sands at the Office of
the Commissioners. of Patents, with his Petition, on the 30th November
1854.
I, JOHN SANDS, of 11, Austin Friars, in the City of London, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN THE MARINER'S
COMPASS to be as follows:-
This Invention has for its object a mode of applying magnets to a mariner's
compass, with a view to neutralize or correct the effects of local attraction.
whether the ship or vessel be of iron or wood. And the improvements
consist of applying a series of magnets around the basin or frame within
which the compass card is suspended, and four or more magnets applied, each
having means of readily adjusting its position in respect to the axis of the
compass card and the magnetic needles combined therewith. It is preferred

page_text: that each compass card should have two magnetic needles fixed parallel to
each other. By this combination of magnets with the mariner's compass, the
local attraction may be so compensated for or adjusted as to leave the
earth's attraction to act without being prejudicially interfered with by the local
attraction.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Sands in the Great Seal Patent Office on the 30th May
1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
SANDS, of No. 11, Austin Friars, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of November, in the year of our Lord One
thousand eight hundred and fifty-four, in the eighteenth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said John
Sands, Her special licence that I; the said John Sands, my executors, adminis-
trators, and assigns, or such others as I, the said John Sands, my executors,
administrators, and 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 THE MARINER'S COMPASS," (a com-
munication from William Graham, of Australia, Master Mariner,) upon the
condition (amongst others) that I, the said John Sands, 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
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in. and by the following statement
thereof (that is to say):-
This Invention has for its object a mode of applying magnets to a mariner's
compass, with a view to neutralize or correct the effects of local attraction,
whether the ship or vessel be of iron or wood. And the improvements consist

page_text: of applying a series of magnets around the basin or frame within which the
compass card is suspended, and four or more magnets are applied, each
having means of readily adjusting its position in respect to the axis of the
compass card and the magnetic needles combined therewith. It is preferred
that each compass card should have two magnetic needles fixed parallel to
each other. By this combination of. magnets with the mariner's compass, the
local attraction may be so compensated for or adjusted as to leave the earth's
attraction to act without being prejudicially interfered with by the local
attraction
Having thus stated the nature of the said Invention, will proceed to
describe the manner of performing the same.
DESCRIPTION OF THE DRAWING..
דיי
Figure 1 shows a plan of a mariner's compass arranged and combined with
magnets according to the Invention Figure 2 is a vertical section, taken at
the line c, d, in Figure 1; and Figure 3 shows part of a vertical section, taken
at the line a, b, in Figure 1. In each of these Figures the same letters are
used to indicate the same parts. A is the compass card; B, B; are two
parallel magnets or magnetic needles fixed to the card, it being prepared to
have two magnets to each card, though that is not essential; but no claim is
made to the use of two magnets to the card of a mariner's compass." C is the
point
nt on which the 'card is supported and on which it turns. The 'correct
height of the point is readily obtained by reason of its being capable of adjust-
ment by ineans of 'the screw stem, as shewn; or in place of having the point
adjustable, the outer axes of the gimbles may each have a screw under it, so
as to raise or lower its point of bearing..
The basin of the compass' is hung on gimbles, as heretofore; and as is shewn
in n the Drawing "D, D, are four magnets arranged in radial positions in
respect to the centre of the card A
The magnets D are placed in grooves in the frame of the compass in such
manner that the horizontal plane in which the magnets' on the compass rotate
coincides with the plane in which the magnets. D, D, are applied. Each
magnet D is capable of being adjusted to or from the compass card, and such
adjustment is preferred to be obtained by means of a screw E' turning in
a suitable bearing at each end, and the screw is capable of being turned by a
button E', fixed on the outer end of the screw, or, what is preferable, by a key
capable of being removed from a square end formed on the axis of the screw.
F is a nut fixed to the magnet D; hence when the screw E is turned in one

page_text: or other direction, the magnet D will be moved to or from the compass card.
By such means may the magnets D be adjusted, in respect to the magnets or
magnetic needles on the compass card, as to neutralize the effects of local
attraction of the ship or vessel in which the compass is employed. I would
remark that it is preferred that each mariner's compass should thus have four
adjustable magnets applied thereto when carrying out the Invention; I do not,
however, confine myself to that number, though I believe such number to
be the most convenient arrangement; and I would state that the means of
attaching and adjusting the magnets D to the frame of a mariner's compass
may be varied without departing from the Invention.
In adjusting the magnets D of a mariner's compass on board a ship.or
vessel, I have found in those cases where this compass has been used, that the
magnets D have all required to have the like poles towards the card A, that is,
either all N. or all S., but it is possible that this may not at all times be the
case. The ship or vessel should be swung in a locality where the true bearings
of the compass are marked on objects on the shore, as is well understood when
adjusting mariner's compasses by magnets as heretofore practised, the ship or
vessel being kept on as level a keel as may be. The compass is to be placed
in the ship so that two of the magnets D shall be fore and aft, or parallel
with the keel, whilst the other two magnets D will be at right angles to the
keel of the ship. Remove the magnets D from the frame, and observe, wben
the ship is placed north and south, whether the north or the south end of the
needle of the compass is attracted by the local attraction. If the local
attraction attracts the north end of the needle, then in placing the magnets D
in position, which are at right angles to the keel, I place the south ends of
those magnets toward the card, and the reverse of the south end is acted on
by the local attraction. Then swing the ship east and west, and observe
whether the north or south end of the compass needle is attracted by the local
attraction. If the north end be attracted, I place the south ends of the other
two magnets D towards the compass needle, and the reverse if the south end
is attracted. The ship or vessel is then to be caused to heel over as much as
she would be liable_to_do_by-a-press-of-sail,-and-then-if-there-be-any-want-of-
correctness observed in respect to the compass card on again bringing the
vessel north and south, such want of correctness is to be obviated and adjusted
by raising or lowering the point C, on which the compass card is supported, or
the gimbles, as before mentioned.
Having thus described the nature of the said Invention, and the manner of
performing the same, I would have it understood that I make no claim to any

page_text: of the parts separately, nor do I confine myself to the details; but what I
claim is, the combining of magnets with mariner's compasses as herein-before
described.
In witness whereof, I, the said John Sands, have hereunto set my hand
and seal, this Twenty-fifth day of May, in the year of our Lord One
thousand-eight hundred and fifty-five.
Witness,
JOHN BUCKTHORPE.
JOHN SANDS. (L.S.)