An Improved Astronomical Model, particularly Adapted to Illustrate the Precession of the Equinoxes.
Year: 1896

page_text: Date of Application, 25th Feb., 1896
Complete Specification Left, 24th. Nov., 1896-Accepted, 16th Jan., 1897
PROVISIONAL SPECIFICATION.
An Improved Astronomical Model, particularly Adapted to Illustrate
the Precession of the Equinoxes.
I HENRY WYLES of 155 Woodhouse Lane, Leeds in the County of York
Surgeon Dentist, do hereby declare the nature of this invention to be as
Follows:-
The object of my invention is to provide a model, which shall clearly and plainly
illustrate the slow backward movement of the equinoxial points along the eliptic;
and comprises the introduction in or combination of a new device with the device
or model now generally used for illustrating the changes of the seasons, though
such latter model may be modified by the application of my invention to illustrate
the precession of the equinoxes only.
My invention is hereunder described as illustrating the precession of the
equinoxes only. It consists of a long arm mounted on a vertical pin or axis
On the said pin or axis is mounted a pulley,
capable of rotation about said axis.
incapable of rotation about the axis. These for the sake of distinction are
designated the fixed pulley and solar axle respectively. The free end of the arm
carries a vertical pin, on which is fitted a second dise pulley, (hereinafter called the
rotable pulley), capable of rotation about the said pin. This pulley carries a long
rod, inclined to the plane of the disc in such a manner as to represent the inclination
of the polar axis to the plane of the eliptic. This rod which for the sake of
distinction is hereinafter designated the polar rod, carries a globe representing the
earth, with the equaterial and tropical and arctic circles marked thereon.
Passing round the fixed and rotable pulleys is placed a tight endless band or
cord, so that when the long arm is rotated, the rotable disc is also rotated.
The fixed pulley is made larger than the rotable pulley. As the cycle of the
precessional movement of the equinoxial points requires 25,000 years to complete,
the diameter of the larger pulley should be booths larger than the diameter of
the smaller pulley to give an exact proportionate illustration of the precessional
movement. As such a proportion is evidently impractible in the case of a model,
I propose as a convenient alteration of this proportion to make the fixed pulley
Tth larger in diameter than the small pulley.
On the long arm are mounted two vertical standards, with holes through them
at the height of the centre of the sphere representing the earth. Through these
holes is passed a long pin rod, which carries at the end vertically above the axle
of the fixed pulley a small sphere to represent the sun. The opposite or pointer
end of the pin rod nearly touches the sphere representing the earth.
It will be evident that on rotating the long arm, the pointer end of the pin rod
will clearly illustrate the backward movement of the equinoxial points along the
eliptic, and still more clearly is the precessional phenomenon indicated by the
change in the direction in which the polar rod points.
By placing a second fixed pulley on the solar axle, and a second rotable pulley
0 on the same in as the first rotable pulley, and making these two pulleys of the
same diameter as the first mentioned rotable pulley, the model can be employed to
illustrate also the change of the seasons, without any precessional movement of
the equinoxes.
and this 24th day of February 1890.
ary 1030.
J. CLARK JEFFERSON,
30 Park Row, Leeds, Agent for Applicant.

page_text: COMILELE,SPECIFICATION.
An Improved Astronomical Model, particularly Adapted to Illustrate
the Precession of the Equinoxes.
I HENRY WYLES of 155 Woodhouse Lane Leeds in the County of York
Surgeon Dentist 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 object of my invention is to provide a model which shall clearly and plainly
illustrate the slow backward movement of the equinoxial points along the ecliptic;
and comprises the introduction in or combination of a new device with the device.
or model now generally used for illustrating the changes of the season, though
such latter model may be modified by the application of my invention to illustrated
the precession of the equinoxes only.
My invention is hereunder first described as illustrating the precession of the
equinoxes only. It consists of a long arm mounted on a vertical pin or axis
capable of rotation about said axis. On the said pin or axis is mounted a pulley
incapable of rotation about the axis. These for the sake of distinction are herein-
after designated the fixed or sun pulley and solar axle respectively. The free end
of the arm carries a vertical pin, on which is fitted a second disc pulley, (hereinafter
called the earth pulley), capable of rotation about the said pin. This pulley
carries a long rod, inclined to the plane of the disc in such a manner as to represent
the inclination of the polar axis to the plane of the ecliptic. This rod which for
the sake of distinction may be suitably hereinafter designated the polar rod,
carries a globe representing the earth, with the equatorial tropical and arctic
circles marked thereon.
Passing round the fixed, i.e. the sun, and the moveable i.e. earth pulleys, is
placed a tight endless band or cord; so that when the long arm is rotated the
rotable disc is also rotated. The sun pulley is made larger than the earth pulley.
As the cycle of the precessional movement of the equinoxial points requires about
25,000 years to complete, the diameter of the larger pulley should be 500gths
larger than the diameter of the smaller pulley to give an exact proportionate
illustration of the precessional movement. As such a proportion is evidently
impracticable in the case of a model, I propose as a convenient alteration to make
the fixed pulley one tenth, or better still one twelvth larger in diameter than the
small pulley.
On the long arm are mounted two vertical standards, with holes through them
at the height of the line passing through the centres of the spheres representing
the sun and the earth. Through these holes is passed a long pin or rod, which
carries at the end vertically above the axle of the fixed pulley a small sphere to
represent the sun; or this sun sphere may be carried at the upper end of a
prolongation of the axis of the sun pulley. The opposite or pointer end of the
pin or rod nearly touches the sphere representing the earth.
It will be evident that on rotating the long arm, the pointer end of the pin rod
will clearly illustrate the backward movement of the equinoxial points, and still
more clearly is the precessional phenomenon indicated by the change in the direction
in which the polar rod points.
By placing a second fixed pulley on the solar axle and a second rotable pulley
on the same pin as the first or earth pulley and making these two pulleye of the
same diameter, the model can be employed to illustrate also the change of the
seasons without any precessional movement of the equinoxes.
And in order that my invention and the manner in which the same is to be

page_text: erformed may be more readily and clearly understood, I have annexed hereto the
ccompanying drawings, in which Fig. 1 is a side elevation, and Fig. 2 a plan of a
nodel constructed according to my invention.
a is a circular base piece, the surface of which is divided by lines into 12 parts
with the signs of the zodiac marked thereon respectively. In the centre of this
pase piece a, a square hole is formed, in which the lower square end of the vertical
support b, carrying the sphere c representing the sun, is fitted. Above the square
end, the support 6 is formed cylindrical for a short distance, over which portion a
corresponding circular hole in the arm d fits, so as to permit the arm d to be rotated
about the sun support b. A pulley e is fixed to the support b concentric therewith,
and immediately over the arm d. The opposite end of the arn d is provided with
a round hole, in which the axis of the earth pulley f fits capable of revolving
therein. In the drawing the sun pulley e is made one twelfth larger in diameter
than the earth pulley f. A steel rod, i.e. the polar rod g is fixed in the proper
inclined position, so that the centre of the sphere h fitted thereon, representing the
earth, is at the same time at the same height above the arm d as the centre of the
sun sphere c, and vertically above the centre of the earth pulley f. i is an endless
cord, passing tightly round both the sun pulley e and the earth pulley f. j is a
steel rod carried on the supports k at the height of the centres of the two spheres,
and from which the sun sphere c may be carried, instead of from the support b.
A second set of pulleys and m of equal diameters may be provided, and
attached to or formed in one piece with the pulleys e and frespectively.
In place of the supports k carrying the steel rod j, a support n carrying two-
crossed arms o, as shewn in dotted lines, may be provided for supporting a large
sheet of paper or cardboard at the level of the centres of the spheres to represent
the plane of the ecliptic, and in which two holes are formed to allow for the sun
and earth spheres.
In place of the pulleys and connecting cord, a pitch chain and chain wheels, or
toothed wheels with intermediate gear wheel or wheels may be employed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner, the same is to be performed I declare that what I
claim is :-
1. In astronomical models the device consisting of an arm rotable about a fixed
pulley or wheel and carrying at its free end a pulley or wheel rotable about its
own axis said rotable pulley or wheel being of smaller diameter than the fixed
pulley or wheel in such a proportion as will illustrate in a convenient reduced
number of revolutions a cycle of the precessional phenomenon substantially as set
forth and illustrated.
2. An astronomical model or device consisting of an arm rotable about two fixed
pulleys on a common axial line and fixed to an upright, said upright being fixed to
a base piece, with a sun sphere supported by or above said upright, the free end of
said arm carrying two pulleys rotable about their common axis and secured
together and carrying an inclined polar rod provided with an earth sphere, the
diameter of one of the rotable pulleys being equal to the diameter of one of the
5 fixed pulleys and the diameter of the other rotable pulley being smaller than
the diameter of the other fixed pulley substantially as herein set forth and
illustrated.
Dated this 21st November 1896.
J. CLARK JEFFERSON,
30 Park Row, Leeds, Agent for Applicant.