IMPROVEMENTS IN THE MARINERS COMPASS FOR USE AT SEA AND ELSEWHERE
Year: 1884

page_text: I SYDNEY PITT of Sutton in the County of Surrey Gentleman do hereby declare
the nature of my invention for "IMPROVEMENTS IN THE MARINERS COMPASS FOR
USE AT SEA AND ELSEWHERE' "
a communication to me from abroad by Marinus
Gerardus Vanden Bos of Leyden in the Kingdom of Holland to be as follows:-
This Invention has for its object improvements in the mariners compass for use
at sea and elsewhere.
The improved compass operates by means of a massive wheel which is kept in
very rapid rotation. The axis of the wheel is retained truly horizontal but is
otherwise free and isolated and under these conditions it aligns itself with tho
meridian of the place.
The apparatus is contained in a case supported upon a floating vessel and the
bowl in which this vessel floats is suspended by india rubber bands from the outer
case of the instrument.
The bowl itself also partially floats in another bowl which is similarly suspended.
The inner vessel containing the apparatus is retained in a central position by a
pivot on which it lightly rests, it is provided with a compass card to give the
required indication and with a spirit level to show that the horizontality of the
axis of the heavy fly wheel which it carries within it has been correctly adjusted.
The axis of this wheel is supported so that it may revolve with the least possible
friction in bearings upon standards forming part of a frame. The base of the
frame carries an electro motor or preferably two one on either side balancing each
other. They are connected by bands and pulleys with the axis of the fly wheel.
The wires leading the current to the dynamos are so arranged as not to
constrain in any way the movement of the axis of the fly wheel in the horizontal
plane.
In the place of the dynamo machines a clockwork motor may be substituted.

page_text: COMPLETE SPECIFICATION.
I SYDNEY PITT of Sutton in the County of Surrey Gentleman do hereby declaro
the nature of my invention for "IMPROVEMENTS IN THE MARINERS COMPASS FOR
USE AT SEA AND ELSEWHERE" A communication to me from abroad by Marinus
Gerardus Vanden Bos of Leyden in the Kingdom of Holland, and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement :—
The object of my Invention is to apply the principle of rotation and gravitation
of the earth in the construction of ships, compasses, avoiding the well known
aberrations and imperfections of compasses with magnetized needles giving
consequently always the true meridian, and providing a means of controlling and
correcting ordinary compasses.
The annexed drawing represents a vertical section of the apparatus by which
I realize this object. It is shown to the actual size.
•
The first essential condition is the perfect horizontality of the apparatus and its
complete independence of exterior causes of perturbation.
For this I employ a receiver B attached by a gimbal suspension to the case D of
the compass. The bottom of the receiver, which is of smaller diameter is immersed
in the lower vessel C containing a dense liquid which is not liable to freeze such as
glycerine. This vessel is suspended in the same way as the receiver B.
The suspensions are furnished with rings or bands of india rubber in order to
neutralize the effects of shocks and vibrations.
The arrangements described ensure as much as possible the stability and
immobility of the apparatus; and besides the immersion of the lower part of the
receiver in the dense liquid contributes considerably to relieve the suspension of the
weight of the receiver B and its contents.
The receiver is filled almost to the height of its trunnions with water or other
liquid of small density, to which is added alcohol or other fluid to lower the
freezing point.
In this bath is immersed the case A which contains the essential parts of the
apparatus. These parts are mounted upon a frame composed of a base, on which
are two uprights connected at the top by a bar m. At the bottom of the case A is
attached to serve as a counterpoise, a cylindrical water tight part a it is placed
concentrically with A but is considerably narrower; it is immersed in the lower
contracting part of the receiver B. The bottom of this cylinder a, allows a rod F
to pass. This rod rests centrally upon the bottom of the interior part of the
receiver B, to which it is fixed by a screw.
The upper part of this rod enters a central tube fixed to the interior of the
case A. This tube is closed at the upper part by a stopper f of conical form of
which the point serves as a pivot, and rests in a bearing formed in an enlargement
at the upper part of the rod F, all the moveable parts rest upon this pivot.

page_text: This arrangement serves to centre the case A. exactly and to hold it almost
floating in the liquid in the receiver B.
"
The lower cylinder a is intended to preserve the stability, and to regulate the
flotation.
Upon the upper transverse rod m of the frame, a spirit level M is mounted, the
middle of it coincides with the centre of the apparatus. Two rods rise from the
rod m carrying a compass card N parallel to the axis of the fly L hereinafter
described; all the movements of which it follows and indicates constantly the
position which it takes under the glass cover which closes the top of the compass.
The apparatus is thus in perfect equilibrium and protected from exterior
influences, and returns with certainty to a horizontal position when circumstances
cause it to be displaced from it.
I will now describe the arrangements by the aid of which the orientation is
obtained.
To the two uprights of the frame E. E. are screwed two bearings with binding
screws (see Figure 2) arranged to serve as supports to the pivotting ends of the
horizontal axis H the ends of which are pointed.
Upon the middle of this axis which is mounted in such a manner as to turn
very rapidly and with the least possible friction, there is fixed a fly wheel L having
a heavy rim; the two ends of the axis carry two throated wheels.
Upon the platform of wood or vulcanite forming the base of the frame E are
mounted vertically and in such a way as to balance each other, two small electro
motors G. G. placed on each side of the central tube, the axis of which carries at
either end and actuates another throated wheel. The movement of these wheels
is transmitted by cords to the small wheels of the fly L, so that this turns at a
speed of about 50 revolutions per second in the same direction as the wheels of the
motor. It is advisable for this purpose to give to these wheels a speed of about
25 revolutions per second, to compensate for slipping and loss in transmission.
A fly wheel of about 12%, centimetres in diameter weighing about 1%, kilos
and driven by a force of about 6 to 7 amperes will thus have the requisite speed
imparted to it. In these conditions the heavy fly L in its rapid revolution will
place itself invariably in the direction of the rotary movement of the earth; and
will consequently place its axis in the exact direction to the terrestrial axis, and
the compass card will always show exactly the position of north and south.
The drawing indicates the arrangement of the conducting wires which receive
the current from any source exterior to the apparatus.
-
So as not to interfere in any way with the movements of the floating apparatus,
the transmission of the current is rendered independent by the arrangements
represented. The dome of the case is surmounted for this purpose with a lantern
in which are placed two cups containing mercury.
These cups which are movable are exactly concentric with the movable
apparatus, and by their means the fixed wires communicating with the source of
electricity are kept in contact with the movable wires, which are connected to the
motors by means of the mercury into which their extremities dip, as can be seen
in the drawing.
Many modifications can be made in the arrangements indicated thus, the electro-
motors can be replaced by a single electro-motor a suitable counterpoise being
provided; or they may be replaced by any other description of motor as for
example by a clock movement arranged in such a way as not to derange the
equilibrium of the apparatus.
The fly can also be kept in rotation by the direct action of electricity, by well
known means. The arrangement for the suspension and the floatation may be
simplified by dispensing with the lower basin; and two or even three fly wheels
may be employed in place of one provided they are suitably balanced. The different
details of the construction may also be varied without departing from the essential
characteristics of the invention.

page_text: I am aware that it has been proposed to employ the gyroscope in observations for
ascertaining the longitude and latitude of a place; but there is no analogy.
between that instrument and the one above described; its use being based on the
immobility of the plane in which the rotating part of the gyroscope has been
originally placed and upon its independence of terrestrial influences; whilst in my
apparatus above described the fly in consequence of the peculiar conditions under
which it is placed in order that its axis may always be able to seek and to find
horizontality is so affected by gravitation as to be irresistably attracted to the
plane of rotation of the earth; hence it places its axis in the plane of the terrestrial
axis and indicates the pole with an exactitude unattainable by the magnetised
needle..
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
First. The construction of non-magnetic compasses oriented by the simple effect
of the rapid rotation of a heavy fly so circumstanced that it can control the
position of its axis which thus subjected to the laws of gravitation places
itself automatically in the direction of the movement of the earth, and thus gives
to its axes an exact alignment with the axis of the earth, and consequently places
it in the true meridian, substantially as herein described and represented.
Second. The arrangements described and represented to prevent the influence of
shocks and exterior vibrations upon the compass and to ensure the complete
balance of all its parts under conditions suitable to allow the axis of the fly to
seek and to preserve its horizontality which is an essential condition.
Dated thi 07th J...
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