IMPROVEMENTS IN INCLINATORIUMS OR DIPPING AZIMUTH COMPASSES
Year: 1879

page_text: LETTERS PATENT to John Imray, of No. 28, Southampton Buildings, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN INCLINATORIUMS
OR DIPPING AZIMUTH COMPASSES." A communication from abroad by Joseph
Peichl, at present of Trieste, in the Austrian Empire, Lieutenant in the
Imperial Roval Austrian Navy.
Sealed the 25th May 1880, and dated the 9th December 1879.
PROVISIONAL SPECIFICATION left by the said John Imray at the Office
of the Commissioners of Patents on the 9th December 1879.
JOHN IMRAY, of No. 28, Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN INCLINATORIUMS OR DIPPING AZIMUTH COMPASSES." [A. com-
munication from abroad by Joseph Peichl, at present of Trieste, in the Austrian
Empire, Lieutenant in the Imperial Royal Austrian Navy.]
This Invention relates to a construction of inclinatorium or dipping azimuth
compass which is generally applicable for controlling the correction of compasses,
but more particularly for the compass with universal compensation described in the
Specification to Letters Patent dated 21st September 1878, No. 3758, and which
serves also, independently of any extraneous sighting beyond the ship, firstly, to
ascertain the coefficient of deviation or the total deviation of a compass; secondly,
to ascertain small amounts of the total deviations in the course steered in ships'
azimuths deviating at most 30° from such course; and thirdly, to enable the com-
pensation of the compass in analogous ships' azimuths to be rectified.
The essential parts contained in the apparatus are, firstly, a dipping needle
suspended on gimbals; secondly, an azimuth circle arranged concentric with the
vertical axis of rotation of the dipping needle, and provided with divisions corre-
sponding to the points of the compass; and thirdly, a regulator of the inclination.
In this simple combination however the instrument can only be used under
exceptionally favorable circumstances, and to a very limited extent; in its complete
form, applicable for all cases, the instrument is constructed as follows:-A double
needle mounted as a dipping needle with mirror has its steel or other axis carried
in agate or other bearings in a casing consisting of an upper and a lower part. The
lower part has fixed or formed round its outer surface, at about the level of the axis
of the dipping needle, a horizontal circular disc suspended by diametrically opposite
axes in bearings provided with antifriction rollers on the gimbal ring. The upper
part of the casing is removeable, forming a cover. The axes of the gimbal rings
are carried in a guide ring which can turn concentrically with the vertical axis of
the needle, and which for this purpose rests in a circular seat in a fixed plate, and is
provided with adjusting screws, and an azimuth index.

page_text: At the edge of the circular seat the plate has divisions corresponding to the points
of the compass, but with this difference, that on the right side of the north and south
line are marked the divisions for the western half of the compass card, while those
for the eastern divisions are marked on the left side. The south point of the
divisions corresponds with a stern pointer on the outer edge of the plate, and the
north point with a bow pointer or lubber line, these pointers being again made to
correspond with marks on the fixed outer casing or stand carrying the plate. Other
pointers and corresponding marks are also provided for indicating the direction of
the transverse axis or beam of the ship. The said graduated plate is fixed to the
top of a wooden box, which is placed inside the before mentioned outer casing or
stand with intervening cushions or pads acting as elastic supports, or caoutchouc
suspending bands may be used for this purpose.
For insuring the stability of the instrument a weight is attached to the bottom
of its casing, or to a rod descending therefrom, and this weight may be immersed in
glycerine or other suitable fluid contained in the before mentioned box. In the
upper part or cover of the casing an inclined cylinder projects inwards from a point
in the side lying in the plane of motion of the needle, and in this cylinder is
stretched a horizontal thread. Below the cylinder is an inclined socket fixed to the
disc of the casing, into which socket is inserted a bar carrying at its upper end an
inclined scale, and below this an eye piece. Thus according to the inclination of
the needle the mirror thereof reflects different divisions of the scale towards the
eye piece, so that the observer can by the aid of the intervening stretched thread
read off the degree of inclination of the needle by means of the reflected scale.
A lamp may be fixed on the top of the casing for throwing a light on the scale
so as to enable observations to be made at night.
The bar carrying the scale and eye piece also carries an adjustable small bar
magnet serving as "inclination regulator," and diametrically opposite this bar is a
second inclined socket, also carried by the disc of the casing, into which is fitted
one or more "induction bars" serving to increase the sensitiveness of the apparatus,
or to accelerate the changes of inclination on any change of azimuth of the
needle.
By the use of the inclination regulator and induction bar, which must be arranged
within the gimbal suspensions, the instrument attains in an increased degree the
faculty of indicating corresponding ship and instrument azimuthis, as also generally
any two azimuths of the ship, or of the instrument relating to the same inclinations
of the needle east and west of the magnetic meridian.
For neutralizing the magnetic influences of the ship there are applied to the outer
fixed casing or stand of the apparatus, firstly, one or more cylinders of soft iron
projecting therefrom in a direction athwartships for compensating the transverse
deflecting force of the ship; secondly, a rod or bar of iron at the bottom of the
casing in the direction fore and aft of the ship for compensating the vertical com-
ponents of the ship's magnetism induced horizontally in the fore and aft direction;
and thirdly, either at the top of the casing or stand, or at any other convenient
point, two small opposite adjustable bar magnets in fore and aft positions for
neutralising the semicircular deviating forces of the ship; these last named magnets
are howover only required under special circumstances, and, in fact, the whole
of the above described neutralising appliances although advantageous are not
indispensible.
According to another modification of the apparatus a casing, of the construction
usually employed with inclinatoriums or dipping compasses, with single inclination
needle without mirror may be employed in place of the above described construction
of casing with double needle and mirror.
The lamp and scale bearer are dispensed with in this case, the inclination
regulator being fixed on the casing, and the inclination is observed as in ordinary
dipping compasses by means of a scale provided at the side of the casing. All other
parts remain as above described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Imray in the Great Seal Patent Office on the 8th June
1880.
JOHN IMRAY, of No. 28, Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN INCLINATORIUMS OR DIPPING AZIMUTH COMPASSES." A com-
munication from abroad by Joseph Peichl, at present of Trioste, in the Austrian
Empire, Lieutenant in the Imperial Royal Austrian Navy.
This Invention relates to a construction of inclinatorium or dipping azimuth
compass, by means of which, without extraneous sighting and independently of
changes of geographical latitude, the true or magnetic course can be ascertained,
and consequently the deviations of the steering compasses that are not compensated
be determined, and by which also a constant control of compensated steering
compasses can be effected. The apparatus can also be used as a "goniometer."
The construction of the said apparatus, which is termed "control compass," is
shewn in side olevation and plan respectively at Fig. 1 and Fig. 2 of the
accompanying Drawings. a is a double needle mounted as dipping compass with
prismatic or knife edge axis d, d, regulating weights e, e, and mirror b; it is
contained inside the casing A, A, with the knife edges of its axis resting in semi-
circularly hollowed or otherwise recessed bearings of agate, glass, or jewels. Mounted
in this manner the needle has, in comparison to the intensity and inclination needles
of inclinatoriums, only a very small amount of play for variations of inclination,
and serves only to indicate definite differences of inclination relative to a normal
inclination, or for observing corresponding inclinations at equal distances from the
normal inclination in east and west azimuths, into which however the needle is not
brought by direct rotation of its casing, but by the turning of the ship with certain
settings of the instrument relatively to the azimuth circle for the keel direction.
The course to which the instrument is set and the readings of the steering compass
made at the same moments when during the alternate turning of the ship to port
and to starboard corresponding inclinations, determined by the direction of the
course set, are observed, constitute, together with the turning angle of the ship,
the elements by which according to the present Invention the magnetic or true
course to be steered is obtained, quite independently of the permanent and vertical
induced magnetism of the ship.
The casing A, A, of the needle consists of two halves. The lower half extends to
about the height of the needle axis, and is fixed to or cast in one with the disc-
shaped metal flange B, B, and contains the bearings of the needle axis together
with the stop mechanism r, r. To the bottom of the casing is fixed a hollow rod
carrying a weight L, and adapted to receive within it a vertical induction bar V of
soft iron. The upper half of the casing serves as cover, and may be provided at
top with a lead weight l; u, u, is a conical metal tube passing inwards and closed
at its inner end by a glass cover w having a horizontal thread or line f. The
metal disc B, B, has two sockets h, h', serving to receive the induction bars H, H'.
The bar H carries the scale k, Fig. 3, together with the eye-piece o provided with
a vertical slit; it also carries two magnets R, R, capable of turning on horizontal
axes on cheeks m, m, and serving as inclination regulators. The eye-piece o serves
both for observing inclinations as also for sightings. The induction bar H¹ carries
at its outer end the diopter frame g with the vertical threads for sightings. The
induction bars V, H, H, accelerate the alteration of inclination of the needle caused
by alteration of the course, and thus render the instrument more sensitive than it
would otherwise be. The disc B, B, carries axes D, D, at right angles to the axis
d, d, of the needle, and which may either be knife edges or cylindrical axes running
in bearings with antifriction rollers, the bearings being formed in the gimbal rings
E, E, whose pivots are also formed as knife edges or work on antifriction rollers,
and rest upon the supports F, F, on the guide ring G. The ring G lies in the

page_text: concentric ring P which lies in the ring Q, and the latter is secured to the casing
at the upper edge Z thereof. The rings G and P are concentrically rotatable, and
can be secured together by a pinching screw I. and to the outer ring Q by the
screw II. III. and IV. are metal plates fixed to the under sides of the rings, which,
in conjunction with the screws I. and II., prevent the disarrangement of the system
of rings during transport. S is the steering index on the outer ring Q; p is the
sighting index. Both indices extend to the compass card divisions of the azimuth
circles P, P, that are set to the keel direction.
The instrument is enclosed in the compass box, shewn in dotted lines in Fig. 1,
and it can for special purposes be provided with Airy's semicircular and quadrantal
compensation, in a similar manner to ordinary steering compasses. In most cases,
however, a third inclination regulator R', vertically adjustable or rotatable on a
horizontal axis, is provided perpendicular to the centre, either in the column K or
in the lower part of an ordinary steering compass box if such be employed. The
cap of the casing can be coupled to the supports F, F, by means of brass arms B, B,
so as to be turned horizontally with the instrument;
is a setting screw for
the cap; e, a hinge of the window &, which is arranged to open. The lighting is
effected by means of lamps in the sides of the cover.
The above description of needle could only be employed on one hemisphere
without having its polarity reversed; but if it be provided with a cylindrical axis, or
one with a double or reversible knife edge, and from b to a (Fig. 2) a second mirror
be adapted in such manner that its surface forms a continuation of the surface of
mirror b, the needle can be used on both hemispheres without having its polarity
changed. In order to neutralize the vibrations and shocks to which the ship is
subjected the instrument may be held in an elastic manner between buffers or
cushions or suspended from caoutchouc springs. The cushioning may be effected
by pivotting the gimbal ring E, not directly upon the two supports F, F, but upon
a double ring concentric with E and supported by F, F, between the meeting halves
of which is inserted small caoutchouc tubing or other elastic material. The elastic
suspension can be effected by introducing between the gimbal ring E and the
metal disc B, a concentric ring having symmetrically arranged caoutchouc bands,
the axes D, D, being transferred from B to this ring, and the disc B fastened to the
caoutchouc bands. The ring with bands is so arranged that any shifting of the
disc B, which may be indicated by marks, may be rectified by a uniform shifting of
the bands. In order to put the bands out of action pawls are provided either on
the disc B or on the interposed ring, by means of which the disc can be connected
rigidly with this ring. In order to enable a longer pendulum V, L, to be used, the
apparatus may be mounted either on a tripod or in a cylindrical or conical casing
in which the rod with its weight L can hang down. The regulator R' is in this
case transposed to the lower part of this rod, or it is placed at the side of the
casing.
According to another modification, in place of the casing for the needle shewn in
Figs. 1 and 2, a box shaped casing as with inclinatoriums is used, and the arrange-
ment is such that the inclination is indicated by the upper end of the needle upon
a segmental scale situated in the casing parallel to the vertical plane of the needle
and concentric to its axis, the indications being read off through a side light in the
casing. In this case there is employed in place of the before described needle with
mirror, a longer single or compound needle with knife edge or cylindrical axis, but
without mirror. On the axis may be fixed a rod similar to the tongue of a
balance, and having a vertical position when the needle is in the normal position,
which rod serves to accelerate the alterations of inclination. The scale at k is
dispensed with, and the eye piece at o is only used for sighting. If it be desired
also to dispense with the sighting arrangement, the regulators of inclination R, R,
are transferred to a support fixed to the casing. The other arrangements of the
instrument remain as before described, irrespective of dimensions. The control
compass constructed as above described may also be used as steering compass.

page_text: As shown in Figs. 1, 2, and 3, a regulating weight can be provided at e¹ and at
a, a stop mechanism for the gimbal suspension, and at O', 0, sights in addition to
the main eye piece.
Fig. 4 shews a plan of an instrument which is termed "dromoscope," having for
its object to deterinine without calculation the arithmetical mean of two compass
readings relating to corresponding inclinations, as also to indicate either amplitudes
of the ships' azimuths relating to certain settings of the control compass, and
constant azimuth corrections for all geographical Intitudes, or to indicate definite
deviations of a steering compass. The dromoscope consists of two circular discs
a, a, B, B, which turn separately upon a common axis J, and can be secured to
each other by means of a pinching screw III. The instrument has in addition
two pointers B, S, of equal length, also turning on the centre 8, and linked to equal
jointed arms g, g. A stretched thread fis passed through central perforations of
and of the pin a. The pointer S has an arm extending in the opposite direction
to the edge of the discs, where it can be fixed by the pinching scrow I. By means
of the pinching screw II. the pointer B can be secured rigidly to the arm g. The
disc a, a, contains two concentric circles with the designation "amplitude," and two
concentric compass divisions with the designations "compass course" and " magnetic
course. The two compass divisions are connected together by dotted radial lines,
of which some are extended to the circles of the angles of rotation. They serve for
the graphic representation of the deviation or azimuth correction. The visible
part of the disc ẞ has a compass division concentric with the disc a, a, with the
designation "true course." If the control compass is provided with Airy's
correctors of soft iron, or if it were desired to effect the azimuth corrections by
means of a second azimuth circle introduced between P, P, and Q, Q, Fig. 2, one of
the compass divisions of the disc a, a, and even the disc ß, which is only provided
for the correction of misdirection may be omitted.
"
Having thus described the nature of this Invention and in what manner the
same is to be performed as communicated to me by my foreign correspondent,
I claim,-
First. The herein described improved construction of control compass.
Second. The use of an inclination needle with prismatic or double knife edge
axis within a casing provided with gimbal ring suspension, substantially as herein
described.
Third. The use of the inclination needle provided with one or with two mirrors,
as described, within the needle casing provided with gimbal ring suspension, as
also the use of the before described scale within the gimbal suspension.
Fourth. The use of the induction bars V, H, H¹, or of one or more of them,
whereby the changes of inclination of the needle due to alterations of the course
are accelerated, thus increasing the sensitiveness of the apparatus.
In witness whereof, 1, the said John Imray, have hereunto set my hand and
seal, this Eighth day of June, in the year of our Lord One thousand eight
hundred and eighty.
JOHN IMRAY. (L.S.)