Kitap 2
5.3
The heavens and the earth must be supposed to be divided each into five zones, and the celestial zones to possess the same names as those below. The motives for such a division into zones we have already detailed. These zones may be distinguished by circles drawn parallel to the equator, on either side of it. Two of these will separate the torrid from the temperate zones, and the remaining two, the temperate from the frigid. To each celestial circle there shall be one corresponding on earth, and bearing the same name, and likewise zone for zone. The [two] zones capable of being inhabited, are styled temperate. The remaining [three] are uninhabitable, one on account of the heat, the others because of the extreme cold. The same is the case with regard to the tropical, and also to the arctic circles, in respect of those countries for which arctic circles can be said to exist. Circles on the earth are supposed, corresponding to those in the heavens, and bearing the same name, one for one.
5.3
As the whole heaven is separated into two parts by its equator, it follows that the earth must, by its equator, be similarly divided. The two hemispheres, both celestial and terrestrial, are distinguished into north and south. Likewise the torrid zone, which is divided into two halves by the equator, is distinguished as having a northern and southern side. Hence it is evident that of the two temperate zones, one should be called northern, the other southern, according to the hemisphere to which it belongs. The northern hemisphere is that containing the temperate zone, in which looking from east to west, you will have the pole on your right hand, and the equator on the left, or, in which, looking south, the west will be on the right hand, and the east on the left. The southern hemisphere is exactly the contrary to this.
