IMPROVEMENTS IN SEXTANTS AND OCTANTS, PART OF SAID IMPROVEMENTS BEING APPLICABLE TO TELESCOPES
Year: 1879

page_text: LETTERS PATENT to George Wilson Heath, of Crayford, in the County of
Kent, Nautical Instrument Maker, for the Invention of "IMPROVEMENTS IN
SEXTANTS AND OCTANTS, PART OF SAID IMPROVEMENTS BEING APPLICABLE
TO TELESCOPES."
Sealed the 18th November 1879, and dated the 19th May 1879.
PROVISIONAL SPECIFICATION left by the said George Wilson Heath at the
Office of the Commissioners of Patents on the 19th May 1879.
GEORGE WILSON HEATH, of Crayford, in the County of Kent, Nautical Instru-
ment Maker. "IMPROVEMENTS IN SEXTANTS AND OCTANTS, PART OF SAID IM-
PROVEMENTS BEING APPLICABLE TO TELESCOPES."
The object of one part of this Invention is to improve and simplify the means of
adjustment of the horizon glass in sextants and octants. Heretofore it has been
usual to mount the horizon glass movably in a stationary frame, and adjust it in
the two required directions relatively to the index glass, by means of adjusting
screws working on the horizon glass itself; this is called the fixed horizon adjust-
ment; another mode is to produce the adjustment in one direction by means of a
screw working against the movable glass, and to produce the adjustment in the
other direction by turning the frame on its pivots. This is called the swing horizon
adjustment. Now according to my Invention, I produce both adjustments by
moving the horizon glass frame in the two required directions, and I make the
glass a fixture therein. One mode of carrying this part of my Invention into effect
is as follows: I mount the frame in which the horizon glass is fixed on horizontal
pivots or centres which are carried by a bedplate that at one side is pivotted on
the limb of the instrument; this frame is moved in one direction by means of a
screw working against a projection on the aforesaid bedplate; there is a helical or
other spring pressing on the opposite side of the said projection; the frame is moved
in the other direction by means of a screw pressing against a lower projection from
the frame; there is a helical or other spring pressing in the opposite direction. By
means of a key like a watch key fitting on the square ends of the two adjusting
screws, either of them is moved as required.
Another improvement relates to the construction of the telescope used in con-
nection with the horizon glass, and mounted opposite to it. Heretofore, such
telescopes have been constructed in the ordinary manner, that is, the eye glass with
its tube is moved in and out of the telescope as required for obtaining the focal
range. Now according to my Invention, I make the eye glass stationary, and I
move the object glass within the tubular body of the telescope itself; according to
one mode, I screw the interior of the object glass cell, and I move it within the

page_text: body of the telescope by means of an adjusting sleeve screwed externally, fitting
therein and held by a flange or projection in the front part of the telescope, but so
as to be free to turn. Or I may move the object glass cell by means of an external
screw arranged on one side of the telescope, and connected to the object glass cell ;
or I may use a screw on each side, and actuate them simultaneously by tooth wheel
gear. This improvement is applicable to telescopes in general, and to binocular
glasses" or double telescopes, in which latter case I use one screw between the
two bodies of the instrument, the eye glasses remaining fixtures, and the object
glasses being both connected to the central screw which revolves in situ.
"
Another object of this Invention is to render one and the same telescope for
sextants and octants and telescopes in general (single and binocular), available both
for day and night purposes, or both for short and long ranges. For this purpose, I
make the telescope primarily for night purposes, and I arrange an extra power
lense within the body of the instrument in such a way that it can be swung into
position for day use, and swung out of the way of the vision for night use. I mount
this lense on a bar which, by a lever projecting through the body of the instrument
(or as regards the binocular between the two glasses), can be turned on its centres.
The same arrangement may be applied to neutral tint or other coloured glasses for
subduing intense light.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Wilson Heath in the Great Seal Patent Office on the 19th
November 1879.
GEORGE WILSON HEATH, of Crayford, in the County of Kent, Nautical Instru-
ment Maker. <
IMPROVEMENTS IN SEXTANTS AND OCTANTS, PARTS OF SAID IM-
PROVEMENTS BEING APPLICABLE TO TELESCOPES."
The object of one part of this Invention is to improve and simplify the means of
adjustment of the horizon glass in sextants and octants. Heretofore it has been
usual to mount the horizon glass moveably in a stationary frame, and to adjust it in
the two required directions relatively to the index glass, by means of adjusting
screws working on the horizon glass itself; this is called the fixed horizon adjust-
ment;
another mode is to produce the adjustment in one direction by means of a
screw working against the movable glass, and to produce the adjustment in the
other direction by turning the frame on its pivots; this is called the swing horizon
adjustment. Now according to my Invention, I produce both adjustments by
moving the horizon glass frame in the two required directions, and I make the
glass a fixture therein.
And in order that this part of my Invention may be better understood, I will
now proceed to describe one mode of carrying the same into effect with reference to
the accompanying Drawings, of which Figure 1 is a plan view of a sextant fitted
with my improvements; Figures 2 to 7 are detail views of part of saine, Figure 2
being a separate elevational view of the frame for the fixed horizon glass and parts
connected there with for adjusting it; Figure 3, an end view partly in section, and
Figure 4, plan of underside of same; Figure is a separate elevation view of the
bed plate, and Figure 6, an end view of same, and section through the housing
below same; Figure 7 is a sectional view of the horizon glass and frame. I mount
the frame A in which the horizon glass B, shown in dotted lines in Figure 3, and in
section in Figure 7, is fixed on horizontal pivots or centres a, which are carried by
a bed plate c at one side, pivoted by the fulcrum pin b on the limb D of the instru
ment. b' is a screw tapped up into the fulcrum pin, and 62 is a washer under its
head; the frame A is moved in one direction, that is, round the fulcrum pin b by
means of a screw & working against a projection c¹ on the aforesaid bed plate c;
there is a helical spring c² or other spring pressing on the opposite side of the said
projection c¹, the frame A is moved in the other direction, that is, round the fulcrum
pivots a, a, by means of a screw e pressing against a lower projection ƒ from the
frame A; there is a helical spring y or other spring pressing in the opposite
direction. The bed plate c, the limb D, and the housing E (forming the nut for the
screw d and for the screw e), are formed with sufficiently large holes or internal
spaces for the play or movement of the projections c¹ and f. By means of a key h,
like a watch key, fitting on the square ends of the two adjusting screws d and e,
either of them is moved as required.
Another improvement relates to the construction of the telescope used in con-
nection with the horizon glass, and mounted opposite to it. Heretofore, such
telescopes have been constructed in the ordinary manner, that is, the eye glass with
its tube is moved in and out of the telescope as required for obtaining the focal
range. Now, according to my Invention, I make the eye glass stationary, and I
move the object glass within the tubular body of the telescope itself; according to
one mode, I screw the interior of the object glass cell, and I move it within the
body of the telescope by means of an adjusting sleeve screwed externally fitting
therein, and held by a flange or projection in the front part of the telescope, but so
as to be free to turn. Or I may move the object glass cell by means of an external
screw arranged on one side of the telescope, and connected to the object glass cell,
or I may use a screw on each side, and actuate them simultaneously by tooth wheel
gear. This improvement is applicable to telescopes in general, and to binocular
glasses or double telescopes, in which latter case I use one screw between two

page_text: bodies of the instrument, the eye glasses remaining fixtures, and the object glasses
being both connected to the central screw which revolves in situ.
In Figure 7, I have shown the second mode of carrying this part of my Invention
into effect. The object glass cell G is moved in the body F of the telescope as
required, by means of a nut having a milled edge l', and mounted by and between
plates m and n on the body F; the said nut works on a screw k fixed in a pro-
jection g from the object glass cell G.
Figure 1a is a part sectional view of a sextant telescope made according to the
first named mode. The interior of the object glass cell G is in this case provided
with screw thread inside, and H is a sleeve having external screw thread working
in the cell G. This sleeve H is held by a flange g in the front part of the body F
of the telescope, but so as to turn freely therein..
Figure 8 is a part sectional side view of a binocular of my improved construction,
with moveable object glass cells G, these latter are here in the drawn in position, as
shewn in the sectional part; the two cells G are united to a screw / between them
by a cross connecting piece g to which the said screw is fixed. is a nut working
on the screw k, and. held in the plate m, but free to turn therein.
Another object of this Invention is to render one and the same telescope for
sextants and octants, and telescopes in general, single and binocular, available for
I
day and night purposes, or both for short and long ranges. For this purpose
make the telescope primarily for night purposes, and I arrange an extra power lense
within the body of the instrument in such a way that it can be swung into position
I mount this
for day use, and swung out of the way of the vision for night use.
lense on a bar, which by a lever projecting through the box of the instrument (or as
regards the binocular between the two glasses), can be turned on its centres.
same arrangement may be applied to neutral tint or other colored glasses for sub-
duing intense light.
The
Figure 9 is a face view, and Figure 10, a part sectional end view of a binocular
of ordinary construction, but fitted with my extra power lense; I is the extra
power lense within the body F of the instrument; it is mounted on a fulcrum bar p,
having a small lever or handle q between the two glasses for turning it by, so as to
be in the way of vision as shewn in full lines, or out of vision, as shown in dotted
lines.
The same arrangement is shown in dotted lines as applied to my improved
binocular in Figure 8.
And having thus described and ascertained the nature of this my Invention, and
in what manner the same is or may be performed, I declare that I claim,-
Firstly. Fixing the horizon glass of a sextant or octant, or similar instrument, in
a frame which can be adjusted horizontally on the limb of the instrument, and also
as to deviation from the vertical, substantially as described.
Secondly. Making the object glass cell of a telescope and binocular movable in
the body or bodies of such telescope or binocular by screw appliances, the eye piece
being stationary, substantially as described.
Thirdly. Mounting an extra power lense or a coloured glass for subduing intense
light in the body or bodies of a telescope or binocular, so that it can be turned out
of the line of vision as required, for the purpose of making the instrument available
both for short and long ranges, or for both day and night use, substantially as
described.
In witness whereof, I, the said George Wilson Heatb, have hereunto set my
hand and seal, the Sixth day of November, in the year of our Lord One
thousand eight hundred and seventy nine.