[tied] Re: Why borrow 'seven'? (was: IE right & 10)

--- In cybalist@yahoogroups.com, enlil@... wrote:

> Loreto:
> > Actually it probably is that the oldest calendars have several-
> > numbered days in a week. Four and seven are not the favourites.
>
> ?? Let's get this right. The time it takes for the moon to go

around

> the earth is said to take 27.321661 days, no?

No! That's the sidereal period, i.e. with reference to the fixed
stars. Relative to the Earth-Sun axis (which moves with respect to
the fixed stars), it's a bit over 29 and a half days - remember that
the Moslem year is between 354 and 355 days long.

> The year is approximately 365 days long, for one thing. When you

take

> the lunar cycle in _combination_ with the solar cycle, "seven" is
> really great. The solar year can be approximated using 7 and 52
> (a multiple of 13). So we can approximate 13 lunar cycles in such
> a rounded-off year, or rather 13 monthes... all using nice whole
> numbers. Sweet!

It's a shame it isn't true. Roman consuls only got a 13-month year
if they were on good terms with the pontifex maximus.

Richard.