[Footnote 33: The zones were imaginary bands or circles in the heavens, producing an effect of climate on corresponding belts on the globe of the earth. The frigid zones, between the polar circles and the poles, were considered uninhabitable and unnavigable, on account of the extreme cold. The torrid zone, lying beneath the track of the sun, or rather the central part of it, immediately about the equator, was considered uninhabitable, unproductive, and impassable, on account of the excessive heat. The temperate zones, lying between the torrid and the frigid zones, were supposed to be the only parts of the globe suited to the purposes of life. Parmenides, according to Strabo, was the inventor of this theory of the five zones. Aristotle supported the same doctrine. He believed that there was habitable earth in the southern hemisphere, but that it was forever divided from the part of the world already known by the impassable zone of scorching heat at the equator. (Aristot., Met., ii., cap. v.) Pliny supported the opinion of Aristotle concerning the burning zones. (Pliny, lib. i., cap. lxvi.) Strabo (lib. ii.), in mentioning this theory, gives it likewise his support; and others of the ancient philosophers, as well as the poets, might be cited, to show the general prevalence of the belief.--Cicero, _Somnium Scipionis_, cap. vi.; Geminus, cap. xiii., p. 31; ap. Petavii Opus de Doctr. Tempor. in quo Uranologium sive Systemata var. Auctorum. Amst., 1705, vol. iii.] [Footnote 34: See Appendix, No. X. (see Vol II)]