IMPROVEMENTS IN SHIP AND OTHER COMPASSES
Year: 1876

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN SHIP AND
OTHER COMPASSES." A communication from abroad by Emile Marin Duchemin,
of Paris France.
Sealed the 16th September 1876, and dated the 5th May 1876.
PROVISIONAL SPECIFICATION left by the said William Clark at the Office
of the Commissioners of Patents on the 5th May 1876.
WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex, Patent
Agent. "IMPROVEMENTS IN SHIP AND OTHER COMPASSES."
This Invention relates to constructing compasses with one or more circular
magnets forming a circular compass.
The magnetization may be divided in a ring of magnetized steel, in which case
the two poles will be at opposite extremities of the same diameter. The mag-
notized ring, with or without solution of continuity, when hung on pivots or
otherwise acts in the manner of a needle, its magnetized extremities standing
towards north and south.
A compass more particularly useful for ship's use is composed of a ring of steel
suitably magnetized and supported upon a bar or traverse of iron, copper, aluminium,
or other neutral metal. Or it may consist of a ring of steel suitably magnetized
and supported on a bar of steel magnetized to concord with that of the ring,
whereby a compass card is obtained, the force of which is represented by the
magnetism of the ring and bar. In this case the whole of the metal parts employed
are utilized, and the old arrangement of compass may in this manner be usefully
combined with the circular arrangement.
Both the magnetic and mechanical stability of the circular compass may be
increased by employing a number of concentric rings more or less of semi-spherical,
spheroidal, or spherical form, and either fixed or movable, as desired. The rings
together with the bar uniting them may be cut from one piece of steel in order to
avoid adjustment and the use of screws. The rings may be of round, oval, or
polygonal form.
The card of this improved circular compass will act either in air at the ordinary
ressure, or in compressed air, or in a vacuum, or in or upon any kind of liquid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said William Clark in the Great Seal Patent Office on the 17th October 1876.
WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex, Patent
Agent. "IMPROVEMENTS IN SHIP AND OTHER COMPASSES." A communication from
abroad by Emile Marin Duchemin, of Paris, France.
This Invention consists in mariner's and other compasses constructed with one or
more circular magnets.
If a ring of steel be magnetized it will have two poles at opposite extremities
of the same diameter, and this ring, whether entire or divided, when poised on a
centre or suspended by a thread or otherwise, will behave in the manner of a
magnetic needle, its magnetized extremities standing towards north and south.
It is upon this principle that the present Invention is based.
Thus a ring of steel suitably magnetized and supported by a crossbar of iron,
copper, aluminun, or other neutral metal constitutes an improvement, especially
applicable to mariner's compasses, and if this ring of steel be supported on a cross-
bar of steel, also magnetized, and if the similar poles of the ring and bar be placed
together, a compass is produced, whose power is equal to the magnetism of the
ring added to the magnetism of the bar.
The whole of the metal parts employed are thus actively utilized, and the old
form of compass is usefully combined with the circular arrangement.
I reserve the right-
Istly. Of augmenting the magnetic and mechanical stability of the circular
compass by the addition of concentric magnetized rings, either fixed or movable
as desired.
2ndly. Of making the rings hemispherical, spheroidal, semi-spheroidal, or spherical
in form.
3rdly. Of cutting the rings, together with the crossbar which unite them, out
of a single piece of steel in order to avoid fitting the parts together and the use
of screws.
4thly. Of making the rings of round, oval, or polygonal form.
5thly. Of applying this improved circular compass to work either in air at the
ordinary pressure, in gas, or in compressed air or gas, or in a vacuum, or on or
in a liquid.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is a compass composed of one or more
magnetized circular bars, as described supported in any suitable manner as, for
instance, on a crossbar or crossbars as specified.
In witness whereof, I, the said William Clark, have hereunto set my hand
and seal, this Seventeenth day of October, in the year of our Lord One
thousand eight hundred and seventy-six.
WM. CLARK (L.S)