110 THE WORLD. 



in summer, and also the days being long-er than the nights, and 

 the earth being thus warmed during the day more than it is cooled 

 during the night, this excess of warmth contributes to augment 

 the summer heat. It will also now appear why, although 

 the earth is actually nearer the sun in winter than in the 

 summer, no increase of heat is, on this account, perceived, as the 

 rays, at this time, fall very slanting upon the earth in the northern 

 hemisphere, although in the southern hemisphere, the summer 

 occurring at the time when the sun is nearest the earth, is much 

 warmer than the same season at the north. The lines we have 

 thus seen, apparently marked on the earth by the sun, divide the 

 earth into five zones, or belts. The north frigid; the north tem- 

 perate; the tropical, or torrid; the south temperate ; and the south 



frigid. The first and last are included within the polar circles, 

 and are always cold, inhospitable regions. The temperate /ones 

 are included within the polar circles and the tropics, whilst the 

 tropical, or equatorial regions lie wholly within the two tropics. 

 At the equator, as we have already intimated, and indeed for 

 some distance north and south, nearly to the tropics, perpetual 

 summer reigns, as the sun is, at almost all times vertical at noon; 

 at the equinoxes, it is truly so; but at the time of the summer 

 solstice, it is seen by the inhabitants of the equatorial regions 

 passing between the zenith and the northern horizon, not, how- 

 ever, nearer the north pole, or the polar star, than the rest of the 

 world perceive it ; for to them, the north star is on the horizon. 

 At the time of the winter solstice, it is seen by a spectator at the 



