The Incas erected artificial marks. There were in Cuzco sixteen towers, eight to the west and eight to the east, arranged in groups of four. The two middle ones were smaller than the others, and the distance between the towers was eight, ten, or twenty feet. The space between the little towers through which the sun passed at sunrise and sunset was the point of the solstices. In order to verify this the Inca chose a favourable spot from which he observed carefully whether the sun rose and set between the little towers to east and west. For the observation of the equinoxes richly ornamented pillars were set up in the open space before the temple of the sun. When the time approached, the shadow of the pillars was carefully observed. The open space was circular and a line was drawn through its centre from east to west. Long experience had taught them where to look for the equinoctial point, and by the distance of the shadow from this point they judged of the approach of the equinox. When from sunrise to sunset the shadow was to be seen on both sides of the pillar and not at all to the south of it, they took that day as the day of the equinox. This last account is for Quito, which lies just under the equator. At the spring equinox the maize was reaped and a feast was celebrated, at the autumn equinox the people celebrated one of their four principal feasts[1046]. The months were calculated from the winter solstice. Among the Amazulu, we are told, the path of the sun in winter is different from its summer path: for it travels northward till it reaches a certain place,--a mountain or a forest (where it rises and sets)--and it does not pass beyond these two places; it comes out of its winter house; when it comes out it goes southward to its summer place. We say that when it quits its winter place it is fetching the summer, until it reaches a certain mountain or tree; and then it turns northward again, fetching the winter, in constant succession. These are its houses; we say so, for it stays in its winter house a few days: and when it quits that place we know that it has ended the winter and is now fetching the summer; and indeed it travels southward until, when the summer has grown, it enters the summer house a few days, and then quits it again, in constant succession[1047]. The Basuto also call the summer solstice the house of the sun, and intelligent chiefs adjust the reckoning of the months by it[1048].