Overview
Key data
| Item | Detail |
|---|---|
| Author | Shen Kuo (1031–1095) |
| Completed | c. 1090 |
| Structure | Twenty-six volumes in seventeen sections |
| Astronomically relevant | Volume 7 on numbers and the calendar reform proposals in the “Supplementary Talks” |
The proposal for calendar reform
Shen Kuo proposed reforming the calendar: abandoning the traditional lunisolar calendar
in favour of a purely solar calendar — twelve solar breaths to the year, with months no longer tied to the new moon.
This was a remarkably bold proposal in the history of Chinese calendrics:
the beginning of spring heads the first month of spring, the awakening of insects heads the second, twelve breaths to the year, each a month.
The proposal was not adopted, but its novelty has been acknowledged by later writers.
The theory of eclipses
The work discusses the causes of solar and lunar eclipses, pointing out that a solar eclipse occurs when the sun is covered by the moon
and a lunar eclipse when the moon enters the earth’s shadow, and that eclipses can be computed in advance by regular method.
Such discussion shows that the theory of eclipses was well understood in the Song.
Other technical records
The work also records movable-type printing, the use of the compass and the magnetic declination,
all of them important material for the history of Chinese technology.
Value
Much of what the work records came from Shen Kuo’s own experience or measurement.
For the history of the calendar its twelve-breath proposal is an episode that must be cited.
Compiled and arranged by Chujia Kuang.