As a matter of fact, in later times we get Horus destroying no longer the Hippopotamus or the Crocodile, but _the Thigh of Set_; and, as I have said, 2000 years B.C. the Thigh occupied exactly the same position in the heavens with regard to the pole as the Hippopotamus or the Crocodile did 3000 years before. [Illustration: HORUS AND CROCODILES.] Thus, I think, we may claim that this myth is astronomical from top to bottom; it is as old as, and probably rather older than, Naville thought, because it must certainly have originated in a period somewhere about 5000 years B. C., otherwise the constellation of the Hippopotamus would not have figured in it. The various illustrations of Horus on the crocodiles are a reference to the myth we have just discussed. It is easy to understand that if the myth were astronomical in origin there was no reason why it should be limited to Horus representing the rising sun; we accordingly find it extended to the god Ptah. [Illustration: PTAH AND CROCODILES.] But although I hold that the _astronomical_ meaning of the myth is that the rising sun kills the circumpolar stars, I do not think that is the last word. A conflict is suggested between a people who worship the rising sun and another who worship the circumpolar stars. I shall show in the sequel that there is an astronomical suggestion of the existence of two such distinct races, and that the companions of the sun-god of Edfû must probably be distinguished from the northern Hor-shesu. * * * * * Here we may conclude our reference to the stars which, in the latitude of Egypt, do not rise and set--or, rather, did not rise and set at the epochs of time we have been considering. CHAPTER XV. TEMPLES DIRECTED TO THE STARS. I have now to pass from the circumpolar stars to those which both rise and set. The difference between the two groups--those that do not rise and set and those which do--was fully recognised by the Egyptians, and many references are made to the fact in the inscriptions. In a previous chapter I have given reasons to show that some of the earliest solar temples in Egypt were not oriented to the solstice. The temple of Amen-Rā at Karnak, however, and others elsewhere were built in such a manner that at sunset at the summer solstice--that is, on the longest day in the year--the sunlight entered the temple and penetrated along the axis to the sanctuary. I also pointed out that a temple oriented in this manner truly to a solstice was a scientific instrument of very high precision, as by it the length of the year could be determined with the greatest possible accuracy, provided only that the observations were continued through a sufficient period of time.