TROPICS. (1) Is agronomy, two circles on the celestial sphere, whose distances from the equator are each equal to the obliquity of the ecliptic, or 23;4° nearly. The northern one touches the ecliptic at the sign Cancer, and is thence called the Tropic of Cancer, the southern one being for a similar reason called the Tropic of Capricon. The sun's annual path in the heavens .is bounded by these two circles, and they are called tropics, because when the sun, in his journey northward or southward, reaches either of them, it reverses its polar movement, and turns back. or travels in an opposite direction in regard to north and south. (2) In geography, the tropics are two parallels of latitude, each at the same distance from the terrestrial equator, i.e., 23° 27'. The one north of the equator is called the Tropic of Cancer, and that south of the equator the Tropic of Capricorn. Over these circles the sun is -vertical when farthest north or farthest south, that is, at the solstices, and they include between them that portion of the globe called the torrid zone, or the °tropics,* or tropical regions, a zone al most 47 degrees wide, having the equator for its central line. The Tropic of Cancer passes
through the centre of Mexico, just misses the northern point of Cuba, next invades the Sahara desert, crossing the Nile at Dendur, north of the Nubian desert, cuts Arabia centrally, then passes through northern India, China at Canton and across the island of Formosa to the Pacific Ocean, passing a little north of Hawaii. The Tropic of Capricon crosses Chile, Argentina, Paraguay and southern Brazil, strikes A frica just south of Walfish Bay, in what used to be German territory, cuts through the northern Transvaal and Portuguese East Africa to In hambane Bay; it then passes through southern Madagascar and divides Australia.