A NEW APPARATUS OR ARTIFICIAL HORIZON TO BE ATTACHED TO AND USED WITH THE QUADRANT OR SEXTANT, FOR THE PURPOSE OF TAKING THE ALTITUDES OF CELESTIAL AND OTHER OBJECTS, EITHER ON LAND OR WATER, WITHOUT THE ASSIST- ANCE OF THE NATURAL HORIZON
Year: 1801

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHESTER
GOULD, of Red Lion Street, Clerkenwell, in the County of Middlesex,
Merchant, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Royal Letters Patent under the Great Seal of His United Kingdom
of Great Britain and Ireland, bearing date at Westminster, the Seventeenth
day of November, in the forty-second year of His reign, give and grant
unto me, the said Chester Gould, my executors, administrators, and assigns,
His especial licence that I, the said Chester Gould, my executors, adminis-
trators, and assigns, during the term of years therein mentioned, should and
lawfully might make, use, exercise, and vend, within that part of His
Majesty's United Kingdom of Great Britain and Ireland called England, His
Dominion of Wales, and Town of Berwick-upon-Tweed, my Invention of
"A NEW APPARATUS OR ARTIFICIAL HORIZON TO BE ATTACHED TO AND USED WITH
THE QUADRANT OR SEXTANT, FOR THE PURPOSE OF TAKING THE ALTITUDES OF
CELESTIAL AND OTHER OBJECTS, EITHER ON LAND OR WATER, WITHOUT THE ASSIST-
ANCE OF THE NATURAL HORIZON;" in which said Letters Patent is contained a
proviso obliging me, the said Chester Gould, to particularly describe and
ascertain the nature of my said Invention, and in what manner the same is
to be performed, by an instrument in writing under my hand and seal, and
cause the same to be inrolled in His Majesty's High Court of Chancery within
six calendar months next after the date of the said recited Letters Patent.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Chester Gould, do hereby declare that the nature of iny said Invention,

page_text: and in what manner the same is to be performed, are as follows (that is
to say)-
:-
My Invention consists in applying a fluid or fluids, coloured or otherwise,
to the quadrant or sextant, so as to obtain a level, for the purpose of taking
the altitudes of celestial and other objects on land or water without the
assistance of the natural horizon. This I perform in the following manner,
that is to say: I make a circular tube or ring of brass, or of other proper
substance, from two to three inches in diameter, or more or less, as con-
venience may direct, in which I fit four transparent glasses directly opposite
to and parallel with each other, so that the surfaces of the fluid contained in
the tube may be distinctly seen by the observer. The inside of the tube
which is to contain the fluid may be equal in area to a tube of about one
fourth part of an inch in diameter or even more, and when in use should be
about half filled with some transparent fluid, and it should be fixed to a
small apparatus made of brass or other proper substance, with such joints and
adjustments as are necessary to bring it to it's true position on the quadrant
or sextant.
1
fluid g, g, are
The artificial horizon, represented in the annexed Drawing, I consider to be
most proper for general use.. Figure 5 in the Drawing, represents the whole
instrument of the artificial horizon put together; and Figures 1, 2,.3, and 41
in the Drawing represent it's principal parts asunder. The square shank or
stem a, in Figure 2, enters Figure 1 at b, and is received by the end of the
:screw c, which, being turned, brings it to it's place. The shank d, in Figure 4,
is fixed in the hole e in Figure 2, and is confined by the screw Figure 3.
ffff, in Figure 4 (which is a section of the tube of the artificial horizon)
represent the four places in the sides of the ring or tube where the four
glasses are to be fixed, through which the surfaces of the
intended to be shewn at p, p. h represents a small funnel in the top of the
tube or ring, which is for the purpose of putting the fluid into the tube,
and is stopped with the screw k in the Drawing. L represents a small screw,
which should be taken out when the fluid is put into the tube to let the air
pass out freely. m, in Figure 5 in-the-Drawing, represents-the-screw-which-
binds the cramp n to the frame of the quadrant or sextant, so that the ring or
tube of the artificial horizon will stand directly behind the fore horizon glass.
The position of the tube or ring ought to be such that its plane will be parallel
to the plane of the quadrant or sextant, and so also that the centre of its
glasses, and the hole of the foresight vane of the quadrant or sextant which is
intended to be used, should form a line parallel to the chord of the arch, and
to the plane of the quadrant or sextant at the same time. Its true position on

page_text: the quadrant or sextant being obtained, and the ring or tube being filled, as is
above described, up to the centre of its glasses, as is represented by p, p, in
Figure 4 in the Drawing, and the quadrant or sextant being held in a vertical
position, the surface of the fluid p, p, may be brought to form a perfect level
with the eye of the observer. This being done, the object whose altitude is to
be taken is then reflected down to this fluid level, in the same manner as when
altitudes are taken by a sea horizon. The whole instrument may be varied in
its form, scale, and proportions, and the tube may be filled with mercury,
but I prefer a transparent fluid; and in order to retard the too sudden motion
of the fluid, I make 'an adjustment in the bottom of the tube, either fixed or
moveable, as is represented by o, in Figure 4 in the Drawing, by which the
motion of the fluid is obstructed and regulated at pleasure. I have in some
instances used coloured glasses, but for general use I prefer the plain; in
either case the surface should be well ground and finely polished. I have
also used two tubes or rings, so placed that when the instrument is in use
the level is formed by an apparent contact of one of the surfaces of the fluid
in each tube; but I think a single tube or ring to be much preferable: I
prefer the artificial horizon made and used as above described; but it may be
so constructed as to be connected with a telescope (such as is frequently
applied to quadrants or sextants); by which 'means the surfaces of the fluid,:
and their contact with the image of the sun or any other body, may be-more-
exactly determined, and this may be effected whether the instrument is.
intended to be fitted up with two rings or with one only.
'
As the form of the telescope and of the artificial horizon, as well as the mode
of connecting them together, admit of great variety, I instance the following-
examples, that is to say :-The first example shall be where only one ring or tube
is used. In this case I make the tube of such a figure that one pair of the glasses.
ff, occupy the field of the telescope, between which glasses one of the surfaces.
of the fluid appears, and the other surface of the fluid is put so much out of
the axis of the telescope as not to obstruct the light from the object-glass;
and by placing an horizontal wire, or by drawing an horizontal line across one.
of the glasses f, f, the instrument being previously adjusted and so held or
placed that the surface of the fluid in the tube or 'between the glasses f, f,
and the wire or line is made to correspond, the image of the sun or other
object may be brought to touch the wire or line at the same time by moving
the index of the quadrant or sextant, and the altitude may be read off upon
the arch as in common cases.
The second example shall also be with one tube or ring only; and where
both the surfaces of the fluid 9, 9, shall appear as at p, p, in the field of the

page_text: telescope. In this case I cut off one half of the object glass of the telescope
commonly used, supposing it to be divided by a line parallel to the plane of
the instrument, and, instead of the part taken away, I place half of another
object glass whose focus is equal to one half of the focus of the original object
glass, and I increase the distance between the surfaces of the fluid p, p, to
twice the focal distance of the original glass, and by placing one surface of the
fluid in the field of the telescope, as in the first example, and the other
surface in the axis of the telescope produced, the instrument being adjusted,
that surface of the fluid necessarily placed behind the object glass will appear
to meet the surface of the fluid placed in the field of the telescope, and to
which the image of the sun can be made to coincide, as in the first example.
The last example shall be where two tubes or rings are used. In this case
I place one of the rings or tubes as in the first example, that is to say, one of
the surfaces of the fluid g, g, in the field of the telescope, and the other out
of the axis of the telescope and towards the object glass, and I place the
second ring or tube with one surface in the field of the telescope as near to
the first as possible, and the other surface of the second ring or tube out
of the axis and towards the eye glass of the telescope, the instrument being
adjusted and held or placed so that the two surfaces placed in the field and
both brought into contact with the wire or horizontal line, the image of the
sun or other object may be made to coincide, and the altitude read as in the
two preceding examples.
Although the foregoing description of the artificial horizon is agrecably to
the form in which I now make it, and which, in my opinion, is the best, yet
there are other forms in which it may be made so as to produce nearly the
same effect, for a fluid will become level in a tube made in the form of a
square, parallelogram, or triangle, or any other form, but a circular tube
being more easily made I give it the preference. And notwithstanding I fix
the ring of the artificial horizon at the back side of the fore horizon glass
of the quadrant or sextant, it being suited to the use of both these instru-
ments, yet a good effect may be produced by fixing it to other parts of these
instruments, provided-the-surfaces-of-the-fluid-are_distinctly_seen_by_the
observer either directly or by reflection.
In witness whereof, I, the said Chester Gould, have hereunto set my
hand and seal, the Fourteenth day of May, in the year of our Lord
One thousand eight hundred and two.
CHESTER GOULD. (L.S.)

page_text: AND BE IT REMEMBERED, that on the Fifteenth day of May, in the
year above written, the aforesaid Chester Gould came before our Lord the
King in His Chancery, and acknowledged the Specification aforesaid, and all
and every thing therein contained, in form above written. And also the
Specification aforesaid was stamped according to the tenor of the Statute in
that case made and provided.
Inrolled the same Fifteenth day of May, in the year above written.