We have seen how the Egyptians fixed 360 days as the regular days of their year—12 months of 30 days each, supplemented by 5 additional days at the end of each year. They also marked off 360 degrees in a circle, perhaps by analogy to the yearly circuit of the sun. Sixty, being one-sixth of the 360 and so a natural subdivision in their sexagesimal system, became a convenient subdivision of the circle, and also of each “degree” or each hour.
