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

Hugh Gibbons (hgibbons@hoshi.Colorado.EDU)
11 Jul 1995 03:22:31 GMT

Richard P. Muller ( wrote:

> I think you also have to recognize the significance of the number 12
> to ancient cultures. Many of these cultures had a hard time with
> non-integers, so their number systems had bases that could be divided
> by many smaller numbers.

> I believe that the Sumerian number system was based on 60 (1*2*3*4*5).
> This is also a good explaination also for why there are 60 minutes in
> an hour. Similarly, the number 12 (1*2*3*4) plays a large role in many
> similar cultures. I think that people believed that whatever calendar
> system they chose had to fit into cosmic harmony as they saw it, and
> so they shoe-horned the calendar into 12 months, even though 13 may
> have been more practical.

If you assume that the original definition of the month was based on
the lunar period (full moon to full moon or new moon to new-moon),
twelve would be a closer approximation than 13. (There are
12.37 cycles of the moon per year.)