ASTRONOMICAL SCIENCE

It has been necessary to bear in mind these phases of practical civilization because much that we know

of the purely scientific attainments of the Egyptians is based upon modern observation of their

pyramids and temples. It was early observed, for example, that the pyramids are obviously oriented as

regards the direction in which they face, in strict accordance with some astronomical principle. Early

in the nineteenth century the Frenchman Biot made interesting studies in regard to this subject, and a

hundred years later, in our own time, Sir Joseph Norman Lockyer, following up the work of various

intermediary observers, has given the subject much attention, making it the central theme of his work

on The Dawn of Astronomy.[1] Lockyer's researches make it clear that in the main the temples of

Egypt were oriented with reference to the point at which the sun rises on the day of the summer solstice.

The time of the solstice had peculiar interest for the Egyptians, because it corresponded rather closely

with the time of the rising of the Nile. The floods of that river appear with very great regularity; the

on-rushing tide reaches the region of Heliopolis and Memphis almost precisely on the day of the

summer solstice. The time varies at different stages of the river's course, but as the civilization of the early dynasties centred at Memphis, observations made at this place had widest vogue.