IMPROVE- MENTS IN FLUID COMPASSES
Year: 1866

page_text: LETTERS PATENT to William Ralph Hammersley, of Wigmore Street,.
in the County of Middlesex, Optician, for the Invention of "IMPROVE-
MENTS IN FLUID COMPASSES."
PROVISIONAL SPECIFICATION left by the said William Ralph Hammersley
at the Office of the Commissioners of Patents, with his Petition, on the.
15th June 1866.
I, WILLIAM RALPH HAMMERSLEY, of Wigmore Street, in the County of
Middlesex, Optician, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN FLUID COMPASSES," to be as follows:-
My improvements in liquid compasses consist in the application of an
elastic box or chamber within the bowl or vessel containing the liquid
enveloping the compass whereby to maintain an equal pressure of the fluid
whatever may be the temperature to which it is subject. As well understood
it is imperative that the vessel containing the liquid should contain no air,
and must therefore be quite full of liquid, which when it expands by heat is
liable to burst the glass, or in contracting from cold to draw in air. To protect
the compass from derangement under all temperatures I form a chamber of
two corrugated discs of metal connected by a rim which forms a circular box

page_text: and dispose said box in the body of the fluid containing the compass, which is
introduced under sufficient pressure to exclude all air, the bowl containing
such fluid being hermetically sealed. A passage of communication is
established between the interior of the elastic box and the external atmosphere.
By the expansion of the fluid from heat the box is caused to collapse slightly
and expresses a little of the air contained, while on the contraction of the
fluid the elastic box or case again expands, air entering said box and so
permitting and ensuring its free action; by this means an equal or nearly
equal pressure of fluid is maintained in the compass bowl, and sufficiently so
to prevent any derangement of the compass while subject to the extremes of
temperature to which they are liable to be exposed. Instead of arranging
the air to enter the elastic box as before described I sometimes arrange the
air to take effect on the exterior of the said elastic case and the fluid to enter
therein, for this purpose I form a compartment in the compass bowl or vessel
separated by a suitable partition, into which compartment the external air
has free egress and ingress; I dispose the elastic box in this air compartment
and establish a communication between it and the fluid chamber by a channel
connecting and supporting the elastic box at the centre of one of the discs;
the elastic box is thus free to expand and receive more fluid from the fluid
chamber when the fluid in the said chamber expands from heat, while on
its contracting from cold the fluid again returns into the fluid chamber, the
elastic box at the same time contracting and maintaining the equality of
pressure of the fluid necessary for the proper maintainance and working of
the compass.
A second improvement in liquid compasses consists in the application of
elastic discs and boxes whereby to transmit motion to lever apparatus for
lifting the compass card off the point; for this purpose I prefer to use two
small circular boxes, whose metal sides I prefer to corrugate as before explained;
these boxes are united at their centres and act in concert, the one expanding
while the other contracts, which is reciprocal, so that if placed in the fluid no
difference of pressure is created by motion given to the sides of the boxes.
I prefer, however, to allow the fluid to enter both freely, and separate the
chamber in which they are placed entirely from the fluid of the compass
bowl, which equally affords the means of effecting the object desired. The
two boxes are placed side by side, that is to say, are in the same axial line,
and are united by a collar or neck-like piece between them, they are
also united at each side to the chamber in which they are placed by central
pieces. Motion is imparted to the neck piece between the boxes by a lever
and rod or other means which has no communication or opening into the

page_text: fluid, the motion is thence transmitted by rods and levers
rods and levers open to and dis-
posed in the fluid, the free end of the ultimate lever is under the balance
cone of the card, which is thereby lifted as required. By this
means motion may be communicated to the parts for lifting the card
without affecting the density and pressure of the fluid, and without any
stuffing box or joint to keep tight, through which the motion is transmitted.
In the arrangement where the fluid enters the elastic boxes, as before
mentioned, I transmit tho motion from their uniting neck by a rod
passing freely through a hole in the compass bowl, and the side fixture
of the box thereto, so to speak, is all of a piece therewith, holes also being
bored through the uniting neck for the fluid to pass from one to the
other. Motion is given to the uniting neck by suitable means, which
being on the outside I prefer a nut encircling the chamber containing the
boxes acting on a rod stretched across its diameter. When the boxes are
placed in the fluid I carry the rod from the uniting neck outwards through
the solid of the neck connecting the box with the outer side of the fluid
chamber and apply a lever or other means to actuate it by hand, the trans-
mission of the motion from the exterior of the uniting neck taking place by levers
disposed in the fluid of the compass, in this case free passage for air is provided
between the interiors of the boxes and also to the external air if necessary..
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Ralph Hammersley in the Great Seal Patent
Office on the 15th December 1866..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
RALPH HAMMERSLEY, of Wigmore Street, in 'the County of Middlesex,
Optician, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of June, in the year of our Lord
One thousand eight hundred and sixty-six, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Ralph Hammersley, Her special licence, that I, the said
William Ralph Hammersley, my executors, administrators, and assigns, or
such others as I, the said William Ralph Hammersley, my executors,
administrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islan:ls

page_text: and Isle of Man, an Invention for "IMPROVEMENTS IN FLUID COMPASSES,"
upon the condition (amongst others) that I, the said William Ralph
Hammersley, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Offico within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Ralph Hammersley, do
hereby declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Sheet of Drawings
hereunto annexed, and to the letters and figures marked thereon (that is to
say) :-
A fluid or liquid compass is an ordinary mariner's compass filled with spirits
of wine diluted, which prevents excessive or any undue oscillation of the card.
To fill a liquid compass securely the bowl must be perfectly air-tight, so that
the liquid cannot escape. Supposing such a bowl be completely filled (that
is, without air bubbles) and hermetically sealed, and then subjected to extremo
heat, the liquid will expand more than the bowl, consequently something must
give way to allow the liquid to escape, and the glass being the weakest part
usually cracks. By reason of the fracture the compass is no longer air-tight,
and the fluid escapes, at same time the air having free access to the bowl
will produce air bubbles, and so prevent the card being distinctly seen, in fact
rendering it completely illegiblo in rough weather. On the other hand
supposing we take the bowl when filled and sealed into extreme cold, the
fluid contracts and air bubbles are produced, and resulting in the same
defects. To prevent the possibility of air bubbles arising from either cause
above mentioned I apply a means of compensation whereby the pressure
within the bowl is equalized, and which I apply thereto either internally or
externally of the compass bowl or chamber containing the fluid.
My improvements in fluid compasses consist in the application of an elastic
box or an air chamber by preferenco within the bowl or vessel containing tho
fluid submerging or enveloping the compass. By this means a sufficiently
equal pressure of the fluid is maintained in the bowl, whatever may be the
temperaturo to which it is subject. As well understood and berein-before
explained it is imperative that the chamber or vessel containing the fluid
should contain no air, to ensure which it must be quite full of fluid, but if
uncompensated when the fluid expands by heat it is liable to burst the glass,

page_text: or on the other hand to draw in air by contraction from cold. To protect
the compass from derangement under all temperatures I form a chamber
of two corrugated discs of metal connected by a rim, which together forms a
circular box. I dispose the said box in a body of fluid containing the
compass; this fluid is introduced under sufficient pressure to exclude all air
from the bowl containing it, which is then hermetically sealed. A passage
of communication is established between the interior of the elastic box and
the external atmosphere. By the expansion of the fluid from heat the box is
caused to collapse slightly and to express a little of the air contained, whereas on
the contraction of the fluid the elastic box or caso again expands, air entering
said box, and so permitting and ensuring its free action; by this means an
equal or nearly equal pressure of the fluid is maintained, and sufficiently so
to prevent any derangement of the compass while subject to the extremes of
temperatures to which such instruments are liable to be exposed.
Instead of arranging the air to enter the elastic box, as before described,
I sometimes arrange the air to take effect on the exterior of the said elastic
case, and the fluid to enter therein. For this purpose I form a compartment
in the compass bowl or vessel separated by a suitable partition or otherwise
disposed exterior of the fluid chamber, to which compartment the external
air has free ingress and egress. I dispose the elastic box in this air compart-
ment, and establish a communication between it and the fluid chamber by
a channel connecting and supporting the elastic box at the centre of one of
the discs. The elastic box is thus free to expand and receive more fluid from
the fluid chamber when the fluid in said chamber expands from heat, while
on its contracting from cold the fluid again returns into the fluid chamber,
the elastic box at same time contracting and maintaining the equality of
pressure of the fluid necessary for the proper maintainance and working of the
compass.
The second part of my improvements in fluid compasses consists in the
application of elastic discs and boxes whereby to transmit motion to lever
apparatus for lifting the compass card off the point; for this purpose I use
two small circular boxes, whose metal sides I prefer to corrugate as before
explained; these boxes are united at their centres and act in concert, the one
expanding while the other contracts, which is reciprocal, so that if placed in
the fluid no difference of pressure is created by motion given to the sides of
the boxes. I prefer, however, to allow the fluid to enter both boxes freely
and separate the chamber in which they are placed entirely from the fluid
of the compass bowl, which equally affords the means of effecting the object
desired. The two boxes are placed side by side, that is to say, are in the

page_text: same axial line and are united by a collar or neck-like piece between them;
they are also united at each side to the chamber in which they are placed by
central pieces. Motion is imparted to the neck piece between the boxes by
a lever and rod, or other means which has no communication or opening into
the fluid; the motion is transmitted thence by rods and levers open to and
disposed in the fluid, the free end of the ultimate lever being under the
balance bell or cone of the card, which is thereby lifted as required. By this
means motion may be communicated to parts for lifting the card without
affecting the density and pressure of the fluid, and without any stuffing box
or joint to keep tight, through which the motion would otherwise have to be
transmitted. In the arrangement where the fluid enters the elastic boxes, as
before mentioned, I transmit the motion from their uniting neck by a rod
passing freely through a hole in the compass bowl and the side fixture of the
box thereto (which, so to speak, is all of a piece therewith), holes having
been bored through the uniting neck for the fluid to pass from one to the
other. Motion is given to the uniting neck by suitable means, for which
purpose when exterior of the fluid I prefer to use a nut encircling the
chamber containing the boxes acting on a rod stretched across its diameter.
When the boxes are placed in the fluid I carry the rod from the uniting neck
outwards through the solid of the neck connecting the box with the outer side
of the fluid chamber, and apply a lever or other means to actuate it by hand,
the transmission of the motion from the exterior of the uniting neck taking
place by levers disposed in the fluid of the compass. In this case free passage
for air is provided between the interior of the boxes and the external air, if
.necessary.
DESCRIPTION OF DRAWINGS.
Figure 1 represents a central vertical section of a fluid compass furnished
and arranged according to my Invention.

page_text: the same in the expanded and contracted state.
This elastic box is formed of
two discs 1, 1, of metal corrugated with circular corrugations, as seen in
Figure 2, which shows a disc in plan and in the sections; they are secured to
a rim d of brass or other metal furnished with lugs e, e, whereby the box is
fixed within the bowl B. The discs 1, 1, are formed of silver or are electro-
plated or formed of metal not affected by the fluid in the box. The needles
D, D, should also be similarly coated or encased to prevent oxidation; f is an
air passage from the interior of the box L to the external atmosphere, estab-
lishing free communication therewith. The compass bowl B being air-tight,
as also the box L, the fluid is introduced into the bowl with sufficient pressure
to expel all air from the bowl, this may have the effect of collapsing a little
the sides or discs 1, 1, of the box, but which may be made with a tendency to
bulge somewhat as at Figure 3, so that when the compass is subject to an
ordinary temperature the box may be as at Figures 1 and 4 with the sides or
discs exerting sufficient pressure in an outward direction to maintain the
altitude of the fluid in the bowl and keep the air excluded from that vessel;
when the compass is subject to a high temperature the fluid will expand and
occupying more space will contract the box as at Figure 5; again when
subject to a low temperature the fluid in contracting will occupy a less space
in the bowl, but which will be immediately taken up by the box L expanding
more or less as at Figure 3. In this way an equal or nearly equal pressure
will be maintained in the compass bowl by the compensating action of the
box L immersed in the fluid, whereby all liability to defects arising in the
fluid compass from being subject to the extremes of heat and cold will be done
away with. The fluid has of course free access all round and under the box
L, as seen in the Drawing.
Instead of immersing the box L in the bowl or chamber containing tho
fluid and allowing access of the external atmosphere to the interior of the box,
as before described, I sometimes arrange my elastic box exterior of said fluid
chamber and allow the fluid access to the interior of the box L. The box is
made with the necessary powers of contraction to keep a slight pressure on
the fluid when at a medium temperature, and is free to expand or contract.
Figure 6 is a vertical section of a fluid compass showing this arrangement.
B' is the bottom of the Auid chamber or bowl. Below the bottom B¹ I form
another compartment P, in which I dispose the box L, or it need not be
enclosed at all, but entirely exposed, but I prefer to enclose it as seen, making
an opening g in the false bottom for the free access of the external
atmosphere to the chamber P. The box L is constructed as before described,
excepting that the fixing lugs are dispensed with, the box being wholly

page_text: dependent on the central stem piece h, to which the centre of the upper disc
is soldered or otherwise secured. Through stem h is a passage i for the
ingress and egress of the fluid in the compass bowl to the interior of the box L,
whereby the uniformity of pressure in the fluid chamber is maintained as
before described, the box L expanding and receiving the excess of fluid from
the bowl when it is expanded by heat, and on the contrary supplying the
deficiency of fluid to the bowl when it is contracted by cold, and thus
maintaining the efficiency of the compass under all circumstances, provided the
fluid bowl is made and kept in an air-tight manner and condition.
In order to use the fluid compass as a standard compass in taking azimuths
it is necessary to be able to lift the card to stop it at a given point, as well
understood. For this purpose it is necessary to provide communication from
the exterior of the bowl to the card; this may be done by a rod passing
through a stuffing box, but air is liable to enter from the action of the rod,
and so render the compass more or less defective; to obviate this I provide
a means of communication whereby air cannot possibly enter.
This is repre-
sented in vertical section at Figure 7. According to the first arrangement
it consists of an air-tight chamber R, to which the fluid of the compass has
free access; in this chamber I place two small circular air-tight corrugated
elastic boxes S and T in juxtaposition, being fixed to each other by a neck
piece m at the centre. Box T is fixed to bowl B at n, while box S is
fixed to chamber R at p. The neck piece m is prolonged in the form of a
stem q passing out freely through p. The stem has an air passage in the
centre for the free admission of air to the boxes S and T. Collars on the
projecting part of 9
receive the forked end of a thumb lever U mounted on a
fulcrum at r. By pressing on the free end of lever U the stem 9 will be
drawn outwards, and will have the effect of partially collapsing the box S,
while at same time box T will be expanded; in this action the increased
displacement of box T will be compensated by the decrease in S, and therefore
no effect will be produced on the liquid either by increasing or reducing the
pressure thereof. To the neck piece m is affixed a bent arm W, which enters
the compass bowl by the liquid passage t. This arm being fixed to m, q,
necessarily participates in the lateral motion communicated thereto by lever U,
collars u, u, on arm W embrace the short forked end of a lever X mounted
on fulcrum v, and impart motion thereto. The long end of the lever X
terminates in a flat ring disposed immediately under the mouth of bell E, and
when operated by the means herein-before described lifts the card as shown
dotted. By this means there is no possibility of air entering the fluid
chamber or bowl from the repeated action of the card-lifting apparatus.

page_text: Figure 8 represents a modification of the card-lifting apparatus. In this
arrangement two elastic corrugated boxes S', T", are used. In this case the
fluid of the compass enters said boxes, instead of being exterior thereof, as
before. The boxes are connected by a neck piece m' and attached at n', p',
as before described, but instead of the fluid entering the chamber R in this
it enters the boxes S', T', through passages in n¹, m', having free ingress and
egress thereto. A stem a projects from m', which stem is furnished with the
collars u, u, operating the lever ✗ for the lifting of the compass card, as
before described. The external air enters the case R freely; this caso is
circular, and it has on its circumference a screw, seen in section, Figure 7, to
which a ring or nut y is fitted. This ring y may be readily screwed towards
or from the bowl B, carrying with it a rod z, which is stretched across tho
diameter of the case R; this rod traverses in slots j, j. An annular recess ³, 1ª¹,
is made within the ring y to receive the opposite ends of rod, which ring
therefore moves with it the rod in the slots j, j, towards or from the compass
bowl. The rod passing through neck m' moves the boxes S', T¹, so as to
expand the one and contract the other with the effects before described
with reference to Figure 7, and for the purpose of lifting the compass card as
required.
Having described the nature of my Invention, and the manner of performing
the same, I declare that what I claim as my Invention. to be protected by the
herein-before in part recited Letters Patent is,-
First, the application of an elastic box or case to a fluid or liquid compass,
as and for the purpose herein-before described with reference to Figures 1, 2,
3, 4, 5, and 6 of the Drawings hereunto annexed.
Secondly, the application of apparatus herein-before described and repro-
sented in Figures 7 and 8 to fluid or liquid compasses for the purpose of
establishing communication with and operating on the compass card C, as herein-
before described.
In witness whereof, I, the said William Ralph Hammersley, have hereunto
set my hand and seal, this Twelfth day of December, in the year
of our Lord One thousand eight hundred and sixty-six.
WILLIAM RALPH HAMMERSLEY. (L.s.)