Book 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.
