We can very conveniently study the conditions of observation at the poles of the earth, the equator, and some place in middle latitude, by using an ordinary terrestrial globe. The wooden horizon of the globe is parallel to the horizon of a place at the top of the globe, which horizon we can represent by a wafer. In this way we can get a very concrete idea of the different relations of the observer's horizon in different latitudes to the apparent paths of the stars. We have next to deal with the astronomical relations of the horizon of any place in connection with the worship of the sun and stars at the times of rising or setting, when, of course, they are on or near the horizon; and in order to bring this matter nearer to the ancient monuments, it will be convenient to study this question for Thebes, where they exist in greatest number and have been most accurately described. To adjust things properly we must rectify the globe to the latitude of 25° 40′ N., or, in other words, incline the axis of the globe at that angle to the wooden horizon. It will be at once seen that the inclination of the axis to the horizon is very much less than in the case of London. Since all the stars which pass between the North Pole and the horizon cannot set, all their apparent movement will take place above the horizon. All the stars between the horizon and the South Pole will never rise. Hence, stars within the distance of 25° from the North Pole will never set at Thebes, and those stars within 25° of the South Pole will never be visible there. At any place the latitude and the elevation of the pole are the same. It so happens that all these places with which archæologists have to do in studying the history of early peoples, Egypt, Babylonia, Assyria, China, Greece, &c., are in middle latitudes, therefore we have to deal with bodies in the skies, which do set, and bodies which do not; and the elevation of the pole is neither very great nor very small. In each different latitude the inclination of the equator to the horizon, as well as the elevation of the pole, will vary, but there will be a strict relationship between the inclination of the equator at each place and the elevation of the pole. Except at the poles themselves the equator will cut the horizon due east and due west. Therefore every celestial body which rises or sets to the north of the equator will cut the horizon between the east or west point and the north point; those bodies which do not set will, of course, not cut the horizon at all. The sun, and stars near the equator, in such a latitude as that of Thebes, will appear to rise or set at no very considerable angle to the vertical; but when we deal with stars rising or setting near to the north or south points of the horizon they will seem to skim along the horizon instead of rising or setting vertically.