Improvements in or relating to Instruments for Ascertaining the Latitude or the Altitude of a Place or an Object.
Year: 1899

page_text: Date of Application, 14th July,
1899
Complete Specification Left, 14th Apr., 1900-Accepted, 13th Oct., 1900
Improvements in or relating to Instruments for Ascertaining the
Latitude or the Altitude of a Place or an Object.
I, LEONARD EUGENE COWEY, of Tarkwa Railway, Secondee, Gold Coast, West
Africa, Engineer, do hereby declare the nature of this invention to be as
follows:-
=
The invention relates to instruments for ascertaining the latitude of a place
without reference to the sun or stars as is necessary in the ordinary method;
such instruments being also adapted to be used with advantage for ascertaining
the altitude of mountains, or the depth of shafts.
In marine navigation if it can be ascertained that the point at which a ship
is located is so many feet from the centre of gravity of the earth the latitude
of that point may be very readily ascertained as the observation would be
taken at sea level.
Therefore this being so, if an instrument be so constructed that the distance
from the earth's centre to any point at sea level (or any point at a known dis-
tance above or below sea level) be indicated thereby, the latitude of that place,
(whether in the Northern or the Southern Hemisphere) can be found by a simple
calculation. Inversely should the latitude of any hill or mountain or of any
shaft be known, the altitude or depth compared to sea level of such mountain
or shaft may be easily calculated, if the distance of the top of the mountain,
or of the bottom of the shaft from the earth's centre is known.
It is the object of this invention to design an instrument that will indicate
the distance of any point from the earth's centre of gravity, so as to enable the
aforesaid latitudes or altitudes to be readily ascertained, the construction of the
said instrument being based upon the principle that a body increases in weight
on being brought closer to the centre of gravity.
The said instrument preferably consists of three main parts; two of which
serve as gas holders while the third is in the form of a U-shaped vessel having
one limb of larger diameter than the other. One of the aforesaid gas holders,
hereinafter designated No. 1 gas holder, communicates with the upper end of
the smaller limb and the other hereinafter designated No. 2 gas
holder, communicates with
end of the larger limb. The
the upper
U-shaped vessel is partly filled with mercury or other appropriate
liquid, which is maintained by the gas in gas holder No. 1 at such
a level that the mercury stands higher in the larger limb than in the smaller
limb. The gas in gas holder No. 2 having no weight of mercury to support,
is subjected to less pressure than the gas in the holder No. 1. Should the
instrument thus constructed be brought from a given position to one nearer
the centre of gravity of the earth, the weight of the mercury will increase and
will therefore compress the gas in holder No. 1 and by so doing will cause the

page_text: level of the mercury in the larger limb to descend and that in the smaller limb
to rise. The increase in weight of the mercury is of course only slight and the
fall in level of mercury in the larger limb small, but if the diameter of the
larger limb be made very considerably greater than that of the smaller limb
it will be evident that a very slight fall in the level of the mercury in the larger
limb will cause a very appreciable rise of the mercury in the smaller limb.
The latter is graduated to enable the extent of the movement of the mercury
therein to be conveniently read off and the necessary calculation to be made
to find the latitude or altitude as may be required. The construction of the
instrument with regard to the relative proportions in the diameter of the two
limbs of the instrument would vary considerably in accordance with the circum-
stances under which the instrument would be used.
The effect on the instrument of an increase of temperature would be to increase
the pressure of gas in both of the holders and then the position of the mercury
would be changed somewhat, so that under such conditions a calculation to meet
changes of temperature would be necessary. But in order to counteract the
effect of changes of temperature 1. may decrease the diameter of the larger limb
of the U-shaped vessel at the point where the level of the mercury normally
rests, so that when an increase of temperature causes the gas in the two holders
to expand, the mercury by expanding also, will rise in the larger limb of the
vessel and so compensate for the increase in temperature. By a proper adjust-
ment of the shape and size of the different parts of the apparatus, adequate
compensation may be made for changes of temperature and calculations avoided
as far as possible.
I do not wish to confine myself to the specific form of the apparatus herein-
before described as the same may be varied without departing from my
invention.
Total 141.
TL 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in or relating to Instruments for Ascertaining the
Latitude or the Altitude of a Place or an Object.
I, LEONARD EUGENE COWEY, formerly of Tarkwa Railway, Secondee, Gold
Coast, West Africa, but now of 33, Holborn Viaduct, in the County of London,
Engineer, 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:-
--
The invention relates to instruments for ascertaining the latitude of a place
without reference to the sun or stars as is necessary in the ordinary method;
such instruments being also adapted to be used with advantage for ascertaining
the altitude of mountains, or the depth of shafts or wells.
In marine navigation if the distance of a ship from the centre of gravity
of the earth is known, the latitude of the ship can be very readily ascertained
as the observation would be taken at sea level. This being so, if an instrument
be so constructed that the distance from the earth's centre to any point at sea
level (or any point at a known distance above or below sea level) be indicated
thereby the latitude of that place, (whether in the Northern or the Southern
Hemisphere) can be found by a simple calculation. Similarly should the
latitude of any hill or mountain or of any shaft or well be known, the altitude

page_text: or depth compared to sea level of such mountain or shaft may be easily
calculated.
It is the object of this invention to furnish an instrument that will indicate
the distance of any point from the earth's centre of gravity, so as to enable the
aforesaid latitudes or altitudes or depths to be readily ascertained, the construc-
tion of the said instrument being based upon the principle that a body increases
in weight on being brought closer to the centre of gravity.
The said instrument preferably consists of three main parts; two of which
serve as chambers to contain gas or other aeriform fluid while the third is in
the form of a U-shaped vessel having one limb of larger diameter than the
other. One of the aforesaid aeriform fluid chambers communicates with the
upper end of the smaller limb and the other communicates with the upper
end of the larger limb. The U-shaped vessel contains mercury or other
appropriate liquid, which is maintained by the aeriform fluid in the chamber
connected with the upper end of the smaller limb, at such a level that the
mercury stands higher in the larger limb than in the smaller limb.
The
aeriform fluid in the chamber connected with the larger limb, having no weight
of mercury to support, is subjected to less pressure than the aeriform fluid in
the other chamber. Should the instrument thus constructed be brought from
a given position to one nearer the centre of gravity of the earth, the weight
of the mercury will increase and will therefore compress the aeriform fluid in
the chamber connected with the smaller limb of the U-shaped vessel and by so
doing will cause the level of the mercury in the larger limb to descend and
that in the smaller limb to rise. The increase in weight of the mercury is of
course only slight and the fall in level of mercury in the larger limb is small,
but if the diameter of the larger limb be made very considerably greater than
that of the smaller limb so that the latter will be in the form of a fine bore
tube or capillary tube it will be evident that a very slight fall in the level
of the mercury in the larger limb will cause a very appreciable rise of the
mercury in the smaller limb or tube. The latter may he graduated to enable
the extent of the movement of the mercury therein to be conveniently read
off and the necessary calculation to be made to find the latitude or altitude
as may be required.
In my aforesaid apparatus the body of mercury or other liquid employed is
so arranged as to be isolated or free from the influence of atmospheric pressure
and as far as possible from variations in temperature.
In order that my said invention may be clearly understood and readily carried
into effect I will describe the same more fully with reference to the accom-
panying drawings in which:-
.
Figure 1 is a diagrammatic view shewing the apparatus in its fundamental
form.
Figure 2 is a central vertical section showing the apparatus in a form suit-
able for general use.
Figure is a central vertical section of the lower portion of the apparatus
taken at right angles to Figure 2.
Figures 4, 5 and 6 are transverse sections taken respectively on the lines 1, 1
2, 2 and 3, 3 of Figure 2.
Figure 7 is a detail sectional view of a portion of the apparatus hereinafter
more fully referred to.
Like reference letters indicate similar parts in all the figures.
A is the vessel containing the mercury said vessel being tubular and arranged
in a substantially upright position. B is the fine bore or capillary tube con-
nected with the lower end of the vessel A, said end being bent upward or
U-shaped. C is the aeriform fluid chamber communicating with the upper end
of said tubular vessel A, and D is the aeriform fluid chamber communicating
with the fine bore or capillary tube B. I prefer that the said chamber C shall
contain aeriform fluid at a low pressure or shall be in a vacuous condition

page_text: and that the chamber D shall contain dry air or other aeriform fluid at a pressure
which will depend upon the weight of the mercury and the pressure (when any
exists) in the chamber C.
In Figures 2 to 6 the chamber D, in addition to containing the aeriform fluid,
serves also to enclose the tubular vessel A, and the parts connected therewith.
The capillary tube B instead of forming the smaller vertical limb of the tubular
vessel A as in Figure 1 is made in spiral form so that it can be of considerable
length without occupving much space. The low pressure or vacuum chamber C
is located at the upper end of the tubular vessel A. The chamber 1) is sur-
rounded by another chamber E containing liquid which serves as a jacket for
the chamber D. The upper end of said chamber E is provided with a head or
dome e.
The liquid jacket effectually seals the chamber D and prevents the
surrounding air from percolating its walls and entering the interior thereof.
Any air that might find its way through the chamber E would rise in the liquid
jacket and so pass into the dome e.
The greater portion of the tubular vessel A is likewise provided with a liquid
jacket, by enclosing said vessel in a surrounding tube a containing the liquid so
that any of the aeriform fluid in chamber I that may percolate the wall of said
surrounding tube will ascend into a space at the upper end of said surrounding
tube and be thereby prevented from reaching the interior of the low pressure
or vacuum chamber C.
The said tubular vessel A is supported in position by brackets or bridges a¹ a¹
situated within the chamber D.
In some instances it will be found advantageous to make the passage a³ at
the bend of the U-shaped part of the vessel A very small and to enlarge the
space a above the mercury so that there will be a comparatively large area
of mercury at this part.
The quantity of air displaced through the fine bore tube B by alterations
in the column of mercury in the vessel A would thus be greater than would
otherwise be the case and the movements of the index in the fine bore tube
would consequently be greatly amplified.
I provide means (such as a delicate thermometer F contained within the said
chamber D) for indicating any variations in the temperature thereof. I do
not however confine myself to using only one thermometer nor do confine
myself to the use thereof only in the aforesaid chamber D. Variations in the
temperature of the said chamber D would of course alter the pressure of the
contained acriform fluid and, as a consequence, the height of the column of
mercury would be increased or diminished and the indications of the instru-
ment would be unreliable. In order to compensate for these variations in
temperature and alterations of pressure and the consequent inaccurate indica-
tions, I provide within the chamber D a receptacle G containing alcohol or
similar liquid, such receptacle being connected by a tube g to the upper part gl
of a small chamber g² communicating with the lower part of the tubular vessel A
through a passage g³. The mercury in the tubular vessel A thus has free access
to the chamber and would fill the latter were it not for the fact that the
upper part of said chamber ² contains a cushion of air between the mercury
and the alcohol contained in the receptacle G and the tube g. Therefore if the
temperature of the aeriform fluid in chamber D should for instance rise (thereby
increasing its pressure on the lower end of the mercury column and tending to
cause the level of the said lower end to fall and alter the indication of the
instrument) such rise of temperature would also cause the alcohol in the recep-
tacle G and the tube to expand, thereby compressing the air in the upper
part of the chamber and forcing a certain quantity of the mercury from
the chamber through the passage into the tubular vessel A. This operation
combined with the expansion of the mercury, increases the length of the column
of mercury and thereby counterbalances the pressure of the aeriform fluid in
the chamber D, so that practically no movement of the lower end of the column

page_text: of mercury or alteration in the instrument's indication will take place on
account of the change of temperature. The aériform fluid and the alcohol do
not expand at exactly the same ratio at all temperatures therefore a slight
correction must be made for temperature, as will be well understood.
I prefer to provide in the tube g at a point between the receptacle G and the
chamber. g, a trap constructed as represented in Figure 7; that is to say
the said trap comprises an enlarged portion or bulb on the tube g into which
bulb the upper contracted part or nozzle g of said tube projects. This trap
would prevent the entrance of the alcohol into the upper part 1 of the chamber g
A similar trap at may also be provided on the portion of the fine bore tube B
adjacent to the space a² of the vessel A.
As, in practice, it would not be possible to accurately proportion the different
sizes of the aforesaid chambers and vessels and the quantities of the compensating
liquid used, I provide the chamber 1 with means whereby its capacity and
consequently the pressure of the aeriform fluid which it contains can be slightly
diminished or increased after its manufacture. For this purpose the upper part
of the said chamber D is formed with a cylindrical portion or extension d fitted
with a niston that is capable of being shifted therein by an adjusting screw d³.
By altering the position of the said piston I can slightly vary the capacity of
the chamber D as aforesaid. To prevent the liquid within the dome e from
finding its way between the cylinder and piston, I provide a small quantity of
mercury or other suitable substance at to act as a fluid tight packing.
Within the capillary tube B I provide an index of alcohol or other suitable
substance which will travel along said tube in one or other direction according
as the column of mercury rises or falls by the variations in weight thereof
as hereinbefore explained. The capillary tube is composed of glass so that the
movements of the index can be seen and the said tube may be furnished with
graduations so arranged as to be clearly visible through the walls of the
chambers D and E which are preferably also composed of glass. Or instead of
graduating the capillary tube I may employ a vernier placed contiguous to
the said tube. The said graduations are preferably so arranged that they will
extend consecutively from 0 to 90 which figures will represent consecutive
degrees of latitude between 0° and 90°. When the graduations are thus
arranged the index will directly indicate the latitude at sea level of the place
where the instrument may for the time being be situated.
H is a base to which the apparatus is secured at its lower end and by which
It is maintained in a vertical position. It will be found advantageous to pro-
vide the instrument with means such as those used with a chronometer for keep-
ing it in a truly vertical position when used at sea.
The calculation of the latitude from the indications of the instrument (which
is the principal use to which it would be applied) is effected in the following
manner: viz. Assuming that the instrument is carried on board a ship which
is moving north from the Equator, the weight of the body of mercury will vary
practically only with the latitude, since the instrument will be at sea level or
a few feet above it and by the movement of the mercury or the index in the
smaller limb or capillary tube these variations will be distinctly represented.
Assuming that the weight of the body of mercury were 200 ounces at the
Equator its weight would gradually increase until if it arrived at the North
Pole it would weigh about 201 ounces. Thus if the weight of the mercury at
any point should be 200.5 ounces, the latitude of that place would be roughly
45° north, as this position would be half way between the Equator and the
North Pole. . It will be evident that certain corrections in the indications of the
instrument would be necessary for variations in sea level due to the tides or
otherwise and to the fact that the force of gravity at sea level does not increase
in an absolutely regular proportion as the Poles are approached from the
Equator. These corrections will however be well understood and readily applied
by navigators without requiring further description herein.

page_text: 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
I do not wish to confine myself to the specific form or construction of the
apparatus herein before described in explaining my invention but what I claim
is:-
1. An instrument or apparatus comprising a vessel containing liquid isolated
from atmospheric pressure, and a fine bore index tube through which aeriform
fluid within the apparatus, exerts its pressure to support the said liquid and
by which the indications of the movement of the liquid resulting from variations
in its weight are amplified substantially as and for the purposes specified.
2. An instrument or apparatus having its parts constructed and arranged sub-
stantially as described with reference to Figure 1 or to Figures 2 to 7 of the
accompanying drawings for the purposes specified.
Dated this 14th day of April 1900.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.