A Matter of Degrees

[Doug Millison]

229.30 `incomprehensibly and perversely, in willful denial of God's
Disposition of Time and Space, preferring 365 and a Quarter'  Well why
not?  (AD)

Unless I'm badly misreading (highly possible), this passage seems to say
that the Chinese divided a circle into "365 and a Quarter" degrees,  the
approximate number of days in the year.

I haven't found a reference yet to verify whether or not the Chinese ever
divided a circle into 365.25 degrees, but using the same number for days in
a year and degrees in a circle appears to be an ancient practice, and the
number seems to have been 360 for some time. The Chinese apparently used
the 360 degree model as early as 600 AD:

According to an "Outline of the History of Chinese Mathematics"
(http://aleph0.clarku.edu/~djoyce/mathhist/china.math):
  "By 600 AD....Levensita, Indian astronomer working at State Observatory,
translated two more texts, one of which described angle measurement (360
degrees) and a table of sines for angles from 0 to 90 degrees in 24 steps
(3 3/4  degree) increments.  Hindu decimal numerals also introduced, but
not adopted."

According to Jane Sellers, in her book The Death of Gods in Ancient Egypt
(Penguin, 1992), the Egyptians used 360 for both the number of degrees in a
circle and days in a year:

"The ancient Egyptians...had the world's first sensible calendar. Their
year had twelve 30-day months, giv ing them a 360-day year, with 5 added or
epagomenal days at the end. By 2100 BC, 36 star gods had been set in
relation to this civil calendar and these gods of the heaven appeared on
coffin lids, each god occupying a specific position on the chart or sky
clock for 10-day intervals....The Julian calendar, unlike the Egyptian one,
had an extra day every fourth year; however, over a long period of time it
did acculate error because the year is not exactly 365.25, days long. (Our
Gregorian calendar avoids this by eliminating certain leap years.)"
-pp. 39, 41

Sellars notes that the Babylonian calendar divided the year into 72 weeks
of 5 days each = 360 days. She argues that "Although the date of this is
arguable, at some time ancient man had divided the circle into 360 degrees
and when applied to the aky, a degree was defined as the apparent distance
the sun moved eastward each day when compared to a background of stars."
(p. 194).

Sellars makes these observations in the context of her argument that the
origins of Egyptian religion and myth (especially the Osiris/Isis/Seth
story) can be traced to certain specific astonomical phenomena, especially
a series of total and near total solar eclipses and the gradual shift in
the apparent positions of stars and constellations due to the Precession of
the equinox. She links her theory to number mysticism as explained by
several writers, including Robert Graves, Frances A. Yates, Giergio de
Santillana (Hamlet's Mill:  An Essay on Myth and the Frame of Time).


D O U G  M I L L I S O N ||||||||||| millison at online-journalist.com