in the night sky. Additional tables were used to show how far
the calendar had shifted through the seasons. The two calendars
existing side by side presented no great difficulty. In Egypt
to-day three calendars are in general use—the Arabic (or lunar)
for religious purposes; the Coptic (or Ancient Egyptian) for
agricultural operations; and the European for business dealings
with Europeans and Americans. An almanack showing all three
can be purchased for half a piastre and a surprising interest is
taken in the calendar by all. Those who are able to read are
appealed to by those who cannot—the vast majority.
The dekanal system can be traced back at least as far as the
Third Dynasty (c. 2800 B.C.) and may be older. In later times
the names of the stellar deities were forgotten and became
mutilated beyond recognition. New interest in them was
aroused when the Greeks introduced the twelve signs of the
zodiac (derived from the Babylonians), which were then repre-
sented intermingled with the older pictures of the dekanal
stars. Later the dekans played an important part in astrology,
which developed independently of Graeco-Roman influences.
The day was divided into 24 hours—12 'hours of the day' and
12 'hours of the night5. Observations of the stars were made
by a simple sighting instrument, the merkbet, used (as the
inscriptions record) as an 'indicator for determining the com-
mencement of a festival and for placing all men in their hours'.
Some star diagrams in the tomb paintings of the Twentieth
Dynasty (c. 1200 B.C.) attempt to show the position of the stars
during the 12 hours of the night at intervals of 15 days.
The merklet instrument was also used for alining the axis of
a temple in the ceremonial observed during the laying of founda-
tion stones. In wall scenes depicting the ceremony, the cord,
pegs, and hammers used are represented, and the accompanying
inscriptions refer to observations of the stars determining the
position of the axis.
The hours of the night were determined by water clocks