IMPROVEMENTS IN MAGNETIC COMPASSES
Year: 1882

page_text: LETTERS PATENT to Faustin Betbeder of Foxley Road in the County
of Surrey for an Invention of IMPROVEMENTS IN MAGNETIC COMPASSES
Communicated to him from abroad by Eugène Bourse of Rochefort-sur-Mer
in the Republic of France
PROVISIONAL SPECIFICATION left by the said Faustin Betbeder at the
Office of the Commissioners of Patents on the 28th June 1882.
"
FAUSTIN BETBEDER of Foxley Road in the County of Surrey "IMPROVEMENTS
IN MAGNETIC COMPASSES [A communication to him from abroad by Eugène
Bourse of Rochefort-sur-mer in the Republic of France.]
This invention relates to an improvement in magnetic compasses and is chiefly
designed for mariners compasses and the improvement consists essentially in
floating the compass card upon a liquid instead of hanging it upon a pivotal pin
as usual,
According to this Invention a buoyant float of hemispherical form is fixed to the
underside of the compass card and is partly immersed in a liquid contained in a
bowl fixed in the compass box which is hung on gimbals as usual. The compass
card is provided with a socket at the centre to receive a pivot pin but this pin
which is merely intended to hold the card centrally within the bowl, is placed
above the card instead of beneath as usual, being held in a socket in the glass
cover of the compass box and merely pressos lightly by its own weight or by the
stress of a weak spring, in the socket of the card the point of contact being
coincident with the centre from which the hemispherical surface of the float is
described.
The bowl is provided with an inwardly projecting lip to prevent the liquid
being thrown out by the oscillation of the compass and it is fixed by radial set
screws gripping its foot and thereby adjusted centrally in the compass box.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Faustin Betbeder in the Great Seal Patent Office on the
28th December 1882.
FAUSTIN BETBEDER of Foxley Road in the County of Surrey "IMPROVEMENTS
IN MAGNETIC COMPASSES." A communication to me from abroad by Eugène
Bourse of Rochefort-sur-Mer in the Republic of France
This Invention relates to an improvement in magnetic compasses and is chiefly
designed for mariners' compasses, and the improvement consists essentially in
floating the compass card upon a liquid instead of hanging it upon a pivotal pin
as usual.
According to this Invention a buoyant float of hemispherical form is fixed to the
underside of the compass card, and is partly immersed in a liquid contained in a
glass bowl fixed in the compass box which is hung on gimbals as usual. The
compass card is provided with a socket at the centre to receive an ivory pivot pin,
but this pin which is merely intended to hold the card centrally within the bowl,
is placed above the card instead of beneath as usual, being held in a socket in the
glass cover of the compass box and merely presses lightly by its own weight, or by
the stress of a weak spring in the socket of the card, the point of contact being
coincident with the centre from which the hemispherical surface of the float is
described. The bowl is provided with an inwardly projecting lip to prevent the
liquid being thrown out by the oscillation of the compass and it is fixed by radial
set screws gripping its foot and thereby adjusted centrally in the compass box.
The accompanying drawing represents a central vertical section of the compass.
A is the compass box hung in a gimbal ring in the usual manner. B is the bowl
containing water, to which spirit would be added to prevent freezing in cold
latitudes. C is the compass card and F is the hemispherical float, upon the flat
side of which the card is fixed. D is the ivory pivot pin pressing lightly by its
point in a socket or cavity c truly central to the hemispherical surface of the
float F so that the pin will merely retain the card and float in a central position
within the bowl without otherwise affecting its motion. The float F is hollow and
made of nickel or other metal and is sufficiently buoyant to keep the card
constantly pressed up against its pivot pin D. It is preferably a segment of a
sphere rather greater than a hemisphere and the compass card is fixed upon it in
any suitable manner. The glass bowl B is also preferably of hemispherical form
with an inwardly turned lip 6 to prevent the liquid being thrown out. It has a
foot b' gripped by radial set screws 62 screwing through nuts fixed to the bottom
of the compass box. The card C has a central conical cavity or socket c of metal
to receive the point of pin D as before mentioned and the pin is guided in a socket
clamped in a hole in the glass top A¹ of the compass box, the pin being either loose
in the socket, or pressed down by a light spring.
Having described the nature of the 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 :-
1st The combination with a compass card of a hemispherical float fixed to the
underside of the card and a pivot above resting in a concentrical socket, the float 4
being supported on liquid, substantially as shown and described.
2nd The combination with a float supported and upwardly pivoted compass

page_text: card, of a bowl fixed in the compass box by adjusting screws and provided with an
inwardly turned rim to prevent overflow of the liquid, substantially as shown and
described.
In witness whereof I the said Faustin Betbeder have hereunto set my hand
and seal this twenty seventh day of December, A.D. 1882.
TATICHTIN DEADENED