Kitap 7
1.155
They maintain that the parts of the world are arranged thus. The earth is in the middle answering to a centre; next comes the water, which is shaped like a sphere all round it, concentric with the earth, so that the earth is in water. After the water comes a spherical layer of air. There are five celestial circles: first, the arctic circle, which is always visible; second, the summer tropic; third, the circle of the equinox; fourth, the winter tropic; and fifth, the antarctic, which is invisible to us. They are called parallel, because they do not incline towards one another; yet they are described round the same centre.The κέντρον is rather an axis (namely, a diameter of the celestial sphere) than a point. The zodiac is an oblique circle, as it crosses the parallel circles.
1.156
And there are five terrestrial zones: first, the northern zone which is beyond the arctic circle, uninhabitable because of the cold; second, a temperate zone; a third, uninhabitable because of great heats, called the torrid zone; fourth, a counter-temperate zone; fifth, the southern zone, uninhabitable because of its cold.
