Page:The Rhind Mathematical Papyrus, Volume I.pdf/60

44 Names were given to the months, but each month was also known simply as the ﬁrst, second, third, or fourth of the season to which it belonged. The most striking event of the Egyptian year is the rising of the Nile, which begins in July, and the seasons were named with reference to this event and its consequences. Thus the first season was called the season of the inundation (akhet, mentioned at the beginning of the papyrus and in Number 87), the second season was the season of the “going forth” (prôt) when the vegetation burst forth in the fields as the waters of the river were subsiding, and the third season was the season of summer (shômu, mentioned also in Number 87), when the earth became dry and parched before the coming of the next inundation.

These names show that at ﬁrst the calendar year was made to begin about the time that the Nile began to rise. But the rising of the Nile depends on the solar year, which is about a quarter of a day longer than this Egyptian calendar year, and so the Nile began to rise a day later after four years and a month later after 120 years, and after a time the entire season of the inundation came before the river began to rise, and was the dryest season of the three. They soon found that their year was a “wandering year,” but continued to use it.

The beginning of the rise of the Nile, or any other event that depends on the seasons, is not as regular, nor as easy to determine exactly as some things that may be observed of the stars. The Egyptians early discovered that in the daily apparent revolution of the sun and stars around the earth the stars were continually gaining on the sun. If they watched a star, setting perhaps not long after sunset, they would notice that it set earlier each night than the night before, until at last it would disappear almost before there was darkness enough to make it visible. Then, after a certain number of days, they would see it in the east rising before the sun and appearing in the morning sky as a harbinger of the coming day. They noticed this, in particular, of Sirius, the brightest of all the ﬁxed stars. The day when Sirius ﬁrst appeared as a morning star had a religious significance. We can imagine the priests in the early morning, gazing out over the desert, waiting for the rising of the sun, and then one morning to the south of the place where the sun would appear some one would be the ﬁrst to catch a glimpse of the rising star just as its light was being put out by the advancing sunlight. This was