Re: Why not 13 months? (Was La Systeme Metrique)

Stephen Souter (
7 Aug 1995 06:21:51 GMT

In article <3vaph8$>, (Paul
F. Sagasta) wrote:

> Organization: Internet Thailand, Bangkok, Thailand.
> Distribution: world
> randy ( wrote:
> | (Stephen Souter) wrote:
> | > The chief problem is that 13 happens to be a prime number. This makes it
> | > mathematically impossible to subdivide a year in any satisfactory fashion.
> | > You cannot even divide such a year into the customary four seasons and
> | > hope to come out with the same number of whole months in each season.
> | wel, the seasons start and end with the solstices and equinoxws, which
> | makes this a moot point.
> | > By contrast, a 12-month year can be easily divided into halves
> | > (six-monthly periods), quarters (3-monthly), thirds (4-monthly), and
> | > sixths (bimonthly) of more or less equal size.
> | and what advantage is theere in this?
> One can certainly see the advantage in an easily divisible year.
> However, this pre-supposes that the year was designed to be 12 months. I
> seem to remember, but won't spend a lot of time trying to confirm it,
> that the year once was 10 months, and two months were added to honor
> Julius Augustus something or other. Good they had the good sense then.

Firstly, it was Octavian (ie Caesar Augustus) who changed the *names* of
the two months that are now called July and August to commemorate Julius
Caesar & himself. (If memory serves, he also stole a day from another
month--I forget which one, but probably February--so that July & August
could both have 31 days!)

But neither he nor Julius Caesar (who did make major changes to the
calendar, in 46 B.C.) *added* any months. In fact, Caesar actually
*removed* a month. The pre-Julian calendar did not have leap days.
Instead, it added a 13th month every two years to make the civil calendar
fit the solar year.

As to your mention of a 10-month year, I suspect you are confusing this
with the names for the months of September thru December. "December" is
called this because before Julius Caesar's reforms the Roman year began in
March, which (naturally) made September the 7th month on the calendar,
December the 10th month, & February the 12th.

Stephen Souter