Year: 1885

page_text: I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake, and Co, Patent Agents,
Southampton Buildings in the County of Middlesex 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 mariner's compasses provided with means for auto-
matically compensating for the effect produced thereon by other magnetic forces
than that of the earth.
The construction of the improved compass is based upon the principle of
magnetic attractions and repulsions, and upon the law of Coulomb according to
which the magnetic intensities, are inversely proportional to the square of the
distance.
The said invention consists in the application of the above mentioned law in such
a manner as to produce industrial results, and by the aid of the accompanying
drawing I will describe the construction and the mode of operation of the improved
apparatus.
An ordinary compass A provided with its azimuth-circle is inserted in the upper
end of a tube B which is open at the lower end and slides in a cylindrical tube C,
the lower end of which is closed.
The two tubes B and C are connected with each other by two parallel rods D, D¹
the upper extremities D of which are fixed at diametrically opposite points to the
cylinder B, while the lower extremities D¹ are fixed to the cross piece D¹ K D¹ in
such a manner that the cylinder C, by means of guide-rings d d fixed upon it, can
slide freely upon the tube B.
A screw V connected with the lower end of the tube C serves, with the nut K,
to cause the cylindrical box C to approach, or recede from, the needle N, S of the
compass A, the turning of the said nut in one or the other direction raising or
lowering the tube C upon the tube B.
The bottom of the cylindrical tube C is provided at the centre with the
spherical segment p which is filled with lead or the like in order to maintain the

page_text: axis of the apparatus in a vertical position during the rolling and pitching motions
of the ship.
In the centre of the segment p is a small tube T containing a spiral spring o
which carries a pivot P sliding in the said tube T.
Upon this pivot is mounted a cylindrical box c c which has very thin-sides and
is full of air. Upon the centre of this box is the cap R carrying the needle N¹ S¹
termed the automatic compensator. The box c, c which is connected only with the
needle N¹ S¹ by means of the cap R floats upon a small quantity of petroleum or
other suitable liquid m, m which, being very fluid, permits the magnetized
needle N S¹ to turn freely upon the point of the pivot P according to the
magnetic forces which influence it during the motions of the ship.
Between the cross-piece D1 K D¹ and the bottom of the tube C is the horizontal
bar F of soft iron, which bar is traversed by the rods D D¹ and by means of the
nut fis caused to slide upon the said rods so as to recede from or approach the
automatic compensator N¹ S¹ R.
This bar F which I term the quadrantal multiplier must be arranged like the
compass in the longitudinal direction of the ship. At the bottom of the apparatus
is a magnetized bar N₁ S₁ which is fixed to the azimuth-circle Z and which I term
the semicircular multiplier. This bar Nu Su can be caused to approach, or recede
from the automatic compensator along the screw V by means of the movable
nut f¹, and can be adjusted horizontally so that its poles correspond with those of
the same sign of the permanent magnetism of the ship.
A point or index I placed upon the cross-piece D1 K D¹ serves as an indicator
for the azimuth-circle Z. The whole apparatus is suspended from the gimbals by
the points E E in a binacle having the form of a truncated cone.
HH represents the compass in plan, and as this with its accessories is of ordinary
construction a description thereof is unnecessary.
The whole apparatus is preferably of copper excepting the pieces F, N S, N¹ S¹,
N" S¹¹
The automatic compensator N¹ S¹ can if desired be completely immersed in a
liquid like the compass A. but this arrangement would only augment the weight
and length of the apparatus.
Also the magnetic needles N S of the dial-card N' S¹ of the automatic
compensator and N S of the semicircular multiplier can either be single or
multiple, but I prefer to have them single to simplify the apparatus.
From the above description it will be seen that the essential feature of my
improved compass with an automatic compensating device consists in the combi-
nation of four magnetic elements N S, N¹ S¹, N S and F having their centres of
action on a common vertical axis.
The two magnetic needles, N S of the steering compass A, and S¹ N¹ of the lower
automatic compensator, (under the influence of the fixed magnets, F F of soft iron
and N S of magnetized iron) deviate in opposite directions in direct proportion
to their more or less perpendicular position with regard to the first mentioned
needles, which deviation invariably takes place, whether the three magnetized
needles N S, N¹ S¹, N¹¹ Su are single or whether their force is the resultant of
multiple needles.
It follows accordingly that if under the action of the two artificial magnetic
centres of perturbation F F and N S₁ the two movable needles N S, N¹ S¹, deviate
in opposite directions in the automatic compass under the circumstances indicated,
they deviate much more on board ship when to the magnetic force of these two
artificial centres are added the magnetic forces which naturally exist upon a ship.
By the mechanism described a perfect equilibrium is easily obtained between the
respective forces of attraction and repulsion, so that the steering compass A no
longer deviates from its proper position.
This effect is obtained by placing the magnetic regulators F F and N" S" of the
automatic compensator N¹ S¹ suitably close together and by adjusting the first in

page_text: the direction of the magnetism induced in the soft iron, say in the direction of the
longitudinal axis of the ship by the quadrantal deviation, and the second in the
direction of the permanent magnetism of the ship by the semicircular deviation.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to
me by my foreign correspondent I declare that what I claim is
The improved apparatus consisting of the parts constructed and combined sub-
stantially as described with reference to the accompanying drawing and operating
as set forth.
HASELTINE, LAKE & Co.,
For the Applicant.