Shadows in the Torrid Zone

June 17, 2009

The torrid zone was a term used to refer to the region between the tropics, as explained here by David Abercromby in his Academia scientiarum (1687):

There are five Zones, one Torrid, two Temperate, and two Cold ones. The torrid Zone is comprehended between the two Tropicks; its breadth is 47 degrees, if we reckon according to the common Calcul 23 ½ on each side of the Equator; the two temperate Zones are contain’d between the Tropicks and the Polar Circles, whereof one is South, and the other North; the breadth of both is 43 degrees. The cold Zones are contain’d within the Polar Circles, distant from the Poles of the World 23 degrees ½. (p.50)

In his A short account, of the nature and use of maps as also some short discourses of the properties of the earth (1698), William Alingham described the people inhabiting the various realms of the earth in terms of the shadows they cast:

The Inhabitants of this Zone are called Amphiscians, because they have their shadows both ways at Noon, that is, one part of the Year it is toward the North, the other part toward the South.

The Temperate Zones are those spaces of Earth, included betwixt the Tropicks and Polar Circles, the North temperate Zone being that portion of Earth contained betwixt the Tropick of Cancer and Artick Circle; the South Temperate Zone, is that part or portion of Earth, bounded by the Tropick of Capricorn and Antarctick Circle; each of these Zones are in breadth 43 Degrees, that is, 3010 Miles; in the Northern Temperate Zone, lies almost all Europe and the North part of Africa, as also a considerable part of Asia and America; the Southern Temperate Zone is not so well known to us, it being far distant from our Habitation. These Zones are termed Temperate, because the Sun-beams being cast Obliquely, cannot create that excessive heat, as they do where they fall Perpendicular. They in some measure pertake of the Extremities of Heat and Cold, proceeding from the Torrid and Frigid Zones; those that inhabit in these Zones are called Heteroscians, because their shadows is but one way. (pp.35-7)

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