The massive pylons of some of the Egyptian temples were useful for shading the roofless outer courts. In Greece these were no longer useful. The east front of the Parthenon very much more resembles the temple of Denderah than it does the early Egyptian temple--that is to say, the eastern front is open; it is not closed by pylons. The view as to the possibility of temple-orientation being dominated by astronomical ideas first struck me at Athens and Eleusis, and when I found that the same idea had been held by Nissen, and that the validity of it seemed to be beyond all question, I consulted my friend Mr. F. C. Penrose specially with regard to Greece, as I knew he had made a special study of some of the temples, and that, he being an astronomer as well as an archæologist (for, alas! they are not, as I think they should be, convertible terms), it was possible that his observations with regard to them included the requisite data. I was fortunate enough to find that he had already determined the orientation of the Parthenon with sufficient accuracy to enable him to agree in my conclusion that that temple had been directed to the rising of the Pleiades. He has subsequently taken up the whole subject with regard to Greece in a most admirable and complete way,[183] and has communicated papers to the Society of Antiquaries (February 18, 1892), and more recently to the Royal Society (April 27, 1893) on his results.[184] These results are so numerous and complete that it is now quite possible to trace the transition from Egyptian to Greek temple-worship, and this, with Mr. Penrose's full permission, I propose to do in this chapter. But, in the first instance, I am anxious to state that Mr. Penrose was soon convinced that in Greece, as in Egypt, the stars were used for heralding sunrise. He writes:-- "The object the ancients had in using the stars was to employ their rising and setting as a clock to give warning of the sunrise, so that on the special feast days the priests should have timely notice for preparing the sacrifice or ceremonial, whatever it may have been: "'Spectans orientia solis Lumina _rite_ cavis undam de flumine palmis Sustulit,' etc." I may further give an extract from a letter received from him in which he deals with the demonstration of the orientation hypothesis furnished by the Greek temples alone. "In my paper sent to the Royal Society there was a passage which seems to make it practically _certain_ that heliacal stars were connected with the intra-solstitial temples as derived from Greek sources alone, independent of the powerful aid of the Egyptian cases. "'That the first beam of sunrise should fall upon the statue centrally placed in the adytum of a temple or on the incense altar in front of it on a particular day, it would be requisite that the orientation of the temple should coincide with the amplitude of the sun as it rose above the visible horizon, be it mountain or plain.