5. Once when I borrowed an old book from the library I found a handwritten label which said the book had to be returned 'within a year and a day', a peculiar expression which made me wonder. If a year should be divided in two halves, then 365 days would not be a good measure for a Sun cycle. It must be an even number of days. 364 would do, though. But then there would be 1 day missing. A complete Sun cycle would be 'two years and a day'. The one who wrote 'within a year and a day' could have inherited the idea of 'one more day' from this ancient system of time-reckoning, I thought. The 'time keepers' on Easter Island had no easy task. They had many alternative measures to cope with. One easy way to count the Sun cycle was to use 13 * 14 = 182 days for each half of the year, and this method surely was known all over the world since ancient times. Each 'year' would be 13 fortnights long, and fortnights were used already, I guess, to measure the month. It would be convenient to use the same 'yardstick' for Sun and Moon. The first fortnight measured Waxing Moon and a second measured Waning Moon, together 28 nights in a month. 13 fortnights would measure Waxing Sun and 13 fortnights would measure Waning Sun, together 26 fortnights. 28 was 'shorthand' for the cycle of Moon and 26 became shorthand for the cycle of Sun. Half 28 = 14 and half 26 = 13 were the basic components. Multiplying them created the number of days in the Sun cycle. |