Shen Kua
Astronomer, Shen Kua was born in
China in the year 1026. His family had an
unbroken tradition of being civil
servants. Thus his father was a local
administrator of many posts from
Szechwan in the west to the international port
of Amoy. At Sixteen years old
Shen Kua left his home to travel with his father
from post to post. While
traveling with his father, Shen Kua learned the
responsibilities of a local
administrator. These responsibilities include a
broad range of technical and
managerial problems in public works, finance,
improvement of agriculture, and
maintenance of waterways. In 1051 his father
died and after a two year
mourning period Shen Kua received his first
appointment as a local
administrator at the age of twenty two. Soon after his
appointment he showed
his skill in ability to plan by designing and overseeing a
drainage and
embankment system that reclaimed some hundred thousand acres of
swampland for
agriculture. A few years later he passed the national examinations
and was
assigned a post in Yangchow. While in Yangchow he impressed the
Governor
Chang Ch'u so much that he recommended that Shen be appointed to
the department
of Financial Administration. It was about this time that he
began to study
astronomy. His first works as an astronomer came when he set
down clear
explanations concerning the sphericity of the sun and the moon as
proved by
lunar phases, of eclipse limits and the retrogradation of the lunar
nodes. These
explanations gave the ability to visualize motions in space
Which in the past
was only best implicit in numerical procedures of
traditional astronomy and
seldomly discussed in technical writing. Because of
this work Shen was given an
additional appointed as director of the
Astronomical Bureau. His first project
as director was a major calendar
reform. This reform started with a series of
daily observations of the stars
that lasted over five years. While these
observations where being performed
Shen realized the need for a major redesign
of major astronomical
instruments. The most significant change that Shen made
was to the gnomon.
The gnomon was still being used to measure the noon shadow
and fix the
solstices. Shen redesigned the armillary sphere that is used to make
angular
measurements, and the clepsydra which determines the time that
observations
are made. He improved the armillary sphere by improving the
diameter of the
naked eye sighting tube. Shen noticed that the polestar could no
longer be
seen in the sighting tube at night. He slowly widened the tube by
using the
plots of the polestar three times a night for three months to adjust
the aim.
His new calibration revealed that the tube was slightly three degrees
off.
The clepsydra also had calibration problems as well, in the past day
and
night were separately divided by hours. Shen realized that day and night
hours
were different from season to season. The time was read from float rods
in an
overflow-tank. Shen saw these problems and proposed a new design for
these float
tanks. Shen also made his mark in his discussions of solar,
lunar, and eclipse
phenomena. This by far was the most extraordinary of his
cosmological hypothesis
that accounts for variations in planetary motions
that include retrogradation.
Shen noted that the greatest planetary
anamoloy happened near stationary points.
He proposed a model that
suggested that the planet moved in the shape of a
willow leaf attached to one
side of a periphery circle. The way the planets
changed thier direction of
motion in respect to the stars was explained by the
travel from one point of
the leaf to the other. This served the same purpose as
the epicycle served in
Europe Shen's writings were in part considered to be the
highest achievement
in traditional Chinese mathematical astronomy. After his
impeachment from
office at the age of fifty-one Shen moved to a small piece of
land in the
country. It was there that Shen completed three books and an atlas
of China.
One of these books was called "Brush Talks From The Dream
Brook". This
book includes some of Shen Kua's most elaborate ideas on such
things as
regularities underlying the phenomenal, technical skills,
deliberations of
materia medica, and many miscellaneous
notes.