Improvements in and relating to the Mariners' Compass.
Year: 1895

page_text: Date of Application, 27th Dec., 1895-Accepted, 19th Dec., 1896
COMPLETE
DIEUITIVATION.
Improvements in and relating to the Mariners' Compass.
We, HEINRICH FLORIAN, Nautical Consul of the "Adria" in Fiume, Austria,
and HERMANN SCHOKLITSCH of Vas-Farkasfalva, Hungary, do hereby declare
the nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
This invention relates to the mariners' compass and it has for its object to
remedy any deviations of the magnetic needle due to the presence of a mass of iron
on ship-board.
The annexed drawings show the manner of carrying out the invention.
Fig. 1 is a part section, taken vertically through the compass and compass
bowl.
Fig. 2 is a part section of two correctors which are arranged at an angle of 90°
to each other.
The compass can be either a fluid one or a dry one.
The characteristic, feature of this invention is the compensating devices by
means of which the deviations can be safely, promptly, and conveniently remedied.
In this new compass one or more bars of soft iron are used which, contrary to
the hitherto well-known correctors for quadrantal deviation, are disposed athwart-
ship. The soft iron bar or bars are placed at such a distance below the compass-
card that by the induction of the compass needle itself a negative quadrantal
deviation is produced in such bar or bars of sufficient strength to compensate the
positive deviation of the compass needle.
a varied
-
A similar soft iron bar a produces, according to its distance from the compass
card
(minus) D. The number of degrees forming the amount of
the (plus) D to be compensated is marked on a scale f, divided into degrees
found by trial. For the purpose of correcting the deviations up to twelve degrees
a bar 1 cm. square and 15 cm. loug will be sufficient. In case a stronger force is
wanted more bars are used, 2-4 being employed, all being parallel to one another
and placed across ship. The compass can be easily adjusted by any experienced
captain without the necessity of going out far to sea. The adjustment is effected,
as shown in the accompanying drawing, by a quadrantal corrector consisting of
one or more soft iron bars a of convenient shape, arranged parallel to one another
and across ship.
The said bars are located below the compass card r and receive their
compensating power, i.e. their magnetic power, not from the magnetism of the
earth but from the magnetism of the compass needles. The horizontally induced
magnetism "+D" of the soft iron on board is compensated by approaching or
receding the soft iron bars a, from the compass card r. The corrector therefore
produces an amount of deviation " D" corresponding to the induced positive
magnetism" - D." Up to twenty degrees, the compensation of the positive
quadrantal deviation is effected by the adjustment of the bar, the hand of the scale
being put on the desired degree.
The compensating bar a. may be arranged within the Cardanian suspension or
better still in the binnacle of the compass in which case it is independent of the
compass.
WORKING OF THE QUADRANTAL CORRECTOR.

page_text: needle induces magnetism in the soft iron bar a and as magnetism of the needles
is much stronger than the magnetism of the earth, owing to the nearness of the
compass needle and the soft iron bars a, the induction produced by the earth's
magnetism is very weak especially in view of the smallness of the bar a, but the
induction of the compass needle on the other hand is very powerful, it follows
therefore that the compass needles are attracted by the bar or bars a, that is, a
negative quadrantal deviation is effected.
The magnetism contained in the bars a, which has its origin in the magnetic
power of the earth, is only to be taken into consideration in making mathematical
calculations for the purpose of determining the dimensions of the bar or bars a as
far as it affects the induction of the needles and is of trifling importance. The
power resulting from the earth's magnetism and that of the needles produces a
negative quadrantal deviation. The resulting power acts, therefore, as if no
induction or attraction by the earth took place.
The working of the compensating soft iron bar a is represented in the annexed
diagram (Fig. 3) under the supposition, that the ship is going in the direction of
the dotted arrow i.e. N.E. direction. The compass needles represented by the
winged arrow induce in the compensating soft iron bar the poles S. and N.; the
needle is in consequence of this attracted and thus produced the negative quadrantal
deviation. If the ship is going in the direction of S.E. a positive deviation is
produced in a similar manner; therefore, the effect is such that the original
positive quadrantal deviation of the compass is eliminated.
SEMI-CIRCULAR CORRECTORS.
In this new compass differently constructed correctors are used for correcting
the semi-circular deviation of the needle, and each co-efficient B as well as C is
corrected separately. Two little magnets b serve for compensating B, these
magnets being fitted in an axle g arranged below the quadrantal corrector a; they
may be turned from the vertical position North to the horizontal position by means
of a knob h. In the vertical position of the magnets 6 the south pole points to the
zenith. Therefore, by turning the south pole aft, i.e. towards the stern, the
positive B is compensated; by turning the south pole fore, i.e. towards the stem
the negative B is compensated. The B magnets are of such a force that deviations
amounting to {or +10° to 20° may be compensated therewith. By means of
a pointer b² on a scale b¹ the desired deviation "{or ±B" may be compensated.
The scale b¹ is divided in degrees after trials.
The C magnets c of which four may be used, are placed under the B magnets,
but in a vertical plane and across ship. They are capable of being turned on an
axle . The C magnets in their vertical position point with their north poles to
the zenith. All mathematical quantities of (or ± C up to 10 or 20° are compensated
by placing the pointer (not shown) of this scale on the desired degree of the
scale c. is the turning knob. This arrangement of the B and C correctors is
made for the purpose of compensating easily the additional deviations B and C :
whereas the principal deviation is corrected in the ordinary manner by a magnet
placed in the binnacle of the compass.
The hereinbefore described compass is or may be furnished with a device
whereby the card r can be readily removed from its point d to enable the latter
to be replaced when blunt or broken. The device consists of a cape made with
an inwardly projecting edge or border m at its upper end and of one or more arms
attached to the compass lid or cover. When the card is removed from the point d
it is fastened or hooked by means of the border m on the arm l. The card
being thus held the cap as well as the point can be unscrewed by a special
key and can thus be examined or replaced. This is specially applicable for fluid
compasses.
The compass is provided with a vane or diopter and a shadow pin for ascertaining
deviations when the compass is to be used as an ordinary. one.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
consider novel and desire to claim is :-
1. A compass characterized by the use of one or more soft iron bars a of small
dimensions for compensating the quadrantal deviations, said bar or bars being
arranged in such a manner and at such a distance from the compass needle that
the negative quadrantal deviation (-D) of the bar or bars is produced not by the
inductive action of the earth's magnetism but exclusively by the magnetic power
of the compass needles, substantially as herein before set forth.
2. The arrangement of two semi-circular correctors b and c formed of permanent
magnets of known strength movably pivoted to the compass or in the binnacle the
power of which can be varied by causing the same to turn on their axes, in either
direction from 0 to 20° as marked on suitably graduated scales, substantially as
hereinbefore described with reference to the drawings annexed.
3. In fluid compasses having quadrantal correctors as set forth in Claim 1, the
arrangement of an edge or border m on the cap holder and suitable arm like
rests on the compass lid substantially as and for the purpose herein before set
forth.
Dated thin with law of Drambing 1005
H. D. FITZPATRICK,
70 Wellington Street, Glasgow, Agent.