AN IMPROVEMENT IN THE MARINERS AND OTHER COMPASSES, BY ISOLATING AND RENDERING THEM INSENSIBLE TO THE DISTURBING INFLUENCE OF LOCAL ATTRACTION OF IRON, STEEL, AND OTHER BODIES.
Year: 1854

page_text: LETTERS PATENT to John Biggs, Civil Engineer, of the Parish of
Ightham, in the County of Kent, for the Invention of "AN IMPROVEMENT
IN THE MARINERS AND OTHER COMPASSES, BY ISOLATING AND RENDERING THEM
INSENSIBLE TO THE DISTURBING INFLUENCE OF LOCAL ATTRACTION OF IRON,
STEEL, AND OTHER BODIES.".
•
Sealed the 6th October 1854, and dated the 23rd May 1854.
1
PROVISIONAL SPECIFICATION left by the said John Biggs at the Office
of the Commissioners of Patents, with his Petition, on the 23rd May
1854.
1, JOHN BIGGS, Civil Engineer, of the Parish of Ightham, in the County of
Kent, do hereby declare the nature of the said Invention for "AN IMPROVEMENT
IN THE MARINERS AND OTHER COMPASSES, BY ISOLATING AND RENDERING THEM
INSENSIBLE TO THE DISTURBING INFLUENCE OF LOCAL ATTRACTION OF IRON, STEEL,
AND OTHER BODIES," to be as follows:-
This improvement in the mariners and other compasses is effected
placeing within the box or bowl of the compass a double ring of magnets
concentrically, each ring to be composed of an equal number of 12; 16, 20,
or any greater number of magnets, as may be found necessary, of the
following proportions-Lenght, three and a half; breadth, one and a
quarter;. thickness, one-tenth of an inch. To the center of each of these
magnets is to be firmly revited an armature of soft iron. The magnets are
curved, and exactly fitted to the inside of the compass box; another ring of
magnets are to be curved, so as exactly fit the inside, of the first set of
magnets, with their poles bearing against the armatures; thus forming two

page_text: concentric rings of magnets. The outer ring are to be very carefully magnetized
before they are put into the compass box, with their opposite poles towards
each other; those of the inner ring are not magnetized before they are put in,
but become slightly so in their places. This arrangement connects the magnetic
current, and completly isolates or prevents the disturbing influence of local
attraction of surounding irron, steel, or other metalic bodies used in the con-
struction of ships, on the needles affixed to the cards of the compass, and therby
increase the security of navigation, and produce greater accuracy in surveys
through mineral districts. I claim as original and new Invention the arange-
ment of two or more concentric rings of magnets placed within the compass
box, for the purpose of isolating the needle or needles of the compass, and
and rendering them insensible to the influence of local attraction, and pre-
venting error in the mariners and other compasses; and I firmly beleive
this Invention and discovery will be of the greatest importance in nautical
science to the naval and comercial world, when the extent of human life
and property depending on the accuracy of these important instruments in
navigation is considered.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Biggs in the Great Seal Patent Office on the 20th
• November 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
BIGGS, of the Parish of Ightham, in the County of Kent, Civil Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of May, 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 him, the said
John Biggs, Civil Engineer, Her special licence that he, the said John Biggs,
Civil Engineer, his executors, administrators, and assigns, or such others as he,
the said John Biggs, Civil Engineer, 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 "AN
IMPROVEMENT IN THE MARINERS AND OTHER COMPASSES, AND RENDERING THEM
INSENSIBLE TO THE DISTURBING INFLUENCE OF LOCAL ATTRACTION OF IRON, STEEL,

page_text: AND OTHER BODIES," upon the condition (amongst others) that he, the said John
Biggs, Civil Engineer, by an instrument in writing under his 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Biggs, Civil Engineer, 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, that is to say:-
to
This improvement in the mariners and other compasses is effected by
placing within the bowl or box of the compass a double ring of magnets;
placed concentrically, as shown in the Drawing; each ring is to be composed
of 12, 15, 20, or more magnets, according to size of the compass, of about
the following proportions:-Length, three and a half; breadth, one and a
quarter; thickness, from 1 to 1th of an inch. To the center of each magnet
of the outer ring of magnets is to be firmly revited an armature or peice of
soft iron, about from
th of an inch wide, and of the same thickness as
the inner ring of magnets. The magnets are to be curved, so as to exactly fit
the inside of the compass box. The inner ring of magnets are then fitted with
their poles bearing against the armatures, which, if carefully done, they will
require no other fastening to keep them in their places; they thus form two
concentric rings of magnets. The outer ring is very carefully magnetized, and
placed in the compass box with their opposite poles toward each other; those
of the inner ring are not magnetized before being put into their places, but
become slightly so after. This arrangement connects the magnetic current, and
completely isolates or prevents the disturbing influence of local attraction of
surrounding objects of iron, or steel, or other metalic bodies used in the con-
struction of ships, on the needles, and thereby increases the safety of navigation,
and will produce greater accuracy in surveys through mineral districts.
EXPLANATION OF THE DRAWINGS.
The yellow outer ring is the compass box; the lake-coloured ring is the
outer ring of magnets with its armatures. The parts coloured blue are
the inner ring of magnets, separated by the armatures on the first ring of
magnets.
I claim as original and new the arangement of two or more concentric
rings of magnets, placed within the compass box, for the purpose of isolating
and wondering them insensible to the influence of local

page_text: attraction in the mariners and other compasses, and firmly beleive this Inven-
tion and discovery will be of the greatest importance in nautical science to the
whole naval and commercial world, when the extent of human life, national
and other property, depending on the acuracy of these important instruments
in navigation is considered.
01, 1, the Sand om
seal, this 8th day of November 1854.
S, Have
set my
id an
JOHN, BIGGS.