Ancient Chronology; Calendars and Measurement of time
The frequent and obvious cycles of the moon furnished the earliest measure of time, each cycle being a lunar month.
In Sumer each month began with the new moon, which was carefully observed by the priests.
There were twelve months in the year and when the accumulated shortage (about 11 days each year) became too great and extra month was intercalated, a practice that continued until the reign of Darius (521-485 B.C).
At the summer solstice the rising sun shining straight down the main street of Babylon, furnished a gauge for adjustment of the calendar to the solar year.
In the Lower Egypt the year commenced with the annual rise of the Nile, which begins rather suddenly about the middle of July, a date marked astronomically by the rising at sunrise of the Dog Star, Sirius, the brightest of the fixed stars.
This is a striking event, nowhere more brilliant than in the vicinity of Cairo. In course of time it became evident that the return of Sirius was five days later than the completion of the year of twelve 30 day months, and the year was accordingly lengthened by the addition of five holidays.
The residual shortage of about 6 hours resulted in a slow periodic change of the beginning of the year which would return to its original position in about 1,458 years.
By means this “Sothic cycle,” that the civil calendar of Egypt was introduced in 4236 B.C. not only the earliest fixed date in history, but also the earliest date in the intellectual history of mankind.
The year was divided into three seasons – the inundation, the season of cultivation, and the harvest season.
The months, probably lunar at first, became 30 days, and this continued into historic time.
An edict of 238 B.C. introduced the leap year but the innovation was afterwards forgotten.
The artificial subdivision of the day and night into hours was achieved in Egypt by means of some form of the sun-dial for the day and of the water clock, or clepsydra, for - day and night having each twelve hours of varying lengths.
The earliest time piece known is an elaborate water-clock described by its maker Amenemhet on the wall of his tomb-chapel in the cemetery of Egyptian Thebes about 1550 B.C.
The Babylonians on the other hand by measuring the amount of water escaping slowly from a vessel full ascertained that the tome from the first appearance of the upper edge of the Sun to the moment the whole disk was visible was 1/720 of the entire tome from one sunrise to the next.
This period of day and night was then divided into 12 equal parts, one of which would thus equal twice the modern hours, and is the time required for the sun to travel 60 times its own diameter.
Ancient Chronology; Calendars and Measurement of time
The frequent and obvious cycles of the moon furnished the earliest measure of time, each cycle being a lunar month.
In Sumer each month began with the new moon, which was carefully observed by the priests.
There were twelve months in the year and when the accumulated shortage (about 11 days each year) became too great and extra month was intercalated, a practice that continued until the reign of Darius (521-485 B.C).
At the summer solstice the rising sun shining straight down the main street of Babylon, furnished a gauge for adjustment of the calendar to the solar year.
In the Lower Egypt the year commenced with the annual rise of the Nile, which begins rather suddenly about the middle of July, a date marked astronomically by the rising at sunrise of the Dog Star, Sirius, the brightest of the fixed stars.
This is a striking event, nowhere more brilliant than in the vicinity of Cairo. In course of time it became evident that the return of Sirius was five days later than the completion of the year of twelve 30 day months, and the year was accordingly lengthened by the addition of five holidays.The residual shortage of about 6 hours resulted in a slow periodic change of the beginning of the year which would return to its original position in about 1,458 years.
By means this “Sothic cycle,” that the civil calendar of Egypt was introduced in 4236 B.C. not only the earliest fixed date in history, but also the earliest date in the intellectual history of mankind.
The year was divided into three seasons – the inundation, the season of cultivation, and the harvest season.
The months, probably lunar at first, became 30 days, and this continued into historic time.
An edict of 238 B.C. introduced the leap year but the innovation was afterwards forgotten.
The artificial subdivision of the day and night into hours was achieved in Egypt by means of some form of the sun-dial for the day and of the water clock, or clepsydra, for - day and night having each twelve hours of varying lengths.
The earliest time piece known is an elaborate water-clock described by its maker Amenemhet on the wall of his tomb-chapel in the cemetery of Egyptian Thebes about 1550 B.C.
The Babylonians on the other hand by measuring the amount of water escaping slowly from a vessel full ascertained that the tome from the first appearance of the upper edge of the Sun to the moment the whole disk was visible was 1/720 of the entire tome from one sunrise to the next.
This period of day and night was then divided into 12 equal parts, one of which would thus equal twice the modern hours, and is the time required for the sun to travel 60 times its own diameter.
Ancient Chronology; Calendars and Measurement of time
