Refore that date, the Egyptians had probably learned to imitate the halural irrigation of the Nile foreshores and had developed a rough farmer's calendar by a lunar reckon: ling of 12 moons of 30. days, but thereafter reference to the actual moon was abandoned. The river begins to rise about June 15 owing to the rain coming down from Abyssinia and it was observed that the Star Sirius rose at dawn about this time of year and a year of 365 Jdays independent of the moon was deduced. "About the Fifth dynasty this was connected with the Summer Solstice. The Exyptian calendar of 12 months of 30 days plus 5 days Was continued until Roman times, although it was known to have an error of about a quarter of a [Julius Caesar learned from Egypt his year and corrected the Roman calendar accordingly, giving our present calendar with' Roman months and 305% days. With the quarter Jday correction, the Egyptian system still survives' in Abyssinia and Jamongst the Parsees. Constantine introduced the planetary week which was also an Egyptian invention, Pope Gregory XIII in the 16th century Jomitted 10 days accumulated error jand ordered the future omission of 3 leap years in every 400 years, This is our calendar which Mls the Solar year almost perfectly.
The Chinese were aware of the }365% days sometime prior the Han fdynasly but preferred to retain the true lunar month for ordinary purposes, thus having two calendars, an astronomical one for weather and a Soli-lunar one for chronology which began at the new moon nearest to the 5th February (half way between the Winter solstice andthe Spring equinox). The present Government has abolished this second calendar count of 60 days has also been used since Shang times but has no real er The Mayan Calendar The Mayan calendar, ike the Egyptian one, has 360 days and 5 surplus days, and was divided into 18 periods of 20 days and one of 5 Jdays, while parallel with it was a period of 260 days divided into 13 paris of 20 days. Both systems were used together, coinciding every 52 years, In addition they had a continuous Jcount of days reckoning from an imaginary era about 3000 B.C. taking Jas integers the factors 20 x 18 x 20 20 x 20. This arrangement was also used in parallel with the other
Text read from the printed page and cleaned; old type leaves the occasional error.