ZONE, a division of the terraqueous globe with respect to the different degrees of heat found in its different parts. The zones are denominated torrid, frigid, and temperate. The torrid zone is a band surrounding the terraqueous globe, and terminated by the two tropics. Its breadth is 46° 58'. The equator, running through the middle of it, divides it into two equal parts, each containing 23° 29'. The ancients imagined the torrid zone uninhabitable. The temperate zones are contained between the tropics and the polar circles. The breadth of each is 43° 2'. The frigid zones are segments of the surface of the earth, terminated, one by the antarctic, and the other by the arctic circle. The breadth of each is 46° 58'.