to any part of the north frigid Zone, as shewn by the candle’s shining on it so that the motion of the Globe can carry no place of that Zone into the dark: and at the same time the _south frigid Zone_ is involved in darkness, and the turning of the Globe brings none of it’s places into the light. If the Earth were to continue in the like part of it’s Orbit, the Sun would never set to the inhabitants of the north frigid Zone, nor rise to those of the south. At the Equator it would be always equal day and night; and as the places are gradually more and more distant from the Equator, towards the arctic Circle, they would have longer days and shorter nights, whilst those on the south side of the Equator would have their nights longer than their days. In this case there would be continual summer on the north side of the Equator, and continual winter on the south side of it. [Illustration: Plate V. _J. Ferguson delin._ _J. Mynde Sc._] [Sidenote: PLATE IV. Autumnal Equinox.] But as the Globe turns round it’s Axis, move your hand slowly forward so as to carry the Globe from _H_ towards _E_, and the boundary of light and darkness will approach towards the north Pole, and recede towards the south Pole; the northern places will go through less and less of the light, and the southern places through more and more of it; shewing how the northern days decrease in length, and the southern days increase, whilst the Globe proceeds from _H_ to _F_. When the Globe is at _E_, it is at a mean state between the lowest and highest parts of it’s Orbit; the candle is directly over the Equator, the boundary of light and darkness just reaches to both the Poles, and all places on the Globe go equally through the light and dark Hemispheres, shewing that the days and nights are then equal at all places of the Earth, the Poles only excepted; for the Sun is then setting to the north Pole, and rising to the south Pole. [Sidenote: Winter Solstice.] Continue moving the Globe forward, and as it goes through the quarter _A_, the north Pole recedes still farther into the dark Hemisphere, and the south Pole advances more into the light, as the Globe comes nearer to ♋; and when it comes there at _F_, the candle is directly over the Tropic of Capricorn, the days are at the shortest, and nights at the longest, in the northern Hemisphere, all the way from the Equator to the arctic Circle; and the reverse in the southern Hemisphere from the antarctic Circle; within which Circles it is dark to the north frigid Zone and light to the south. [Sidenote: Vernal Equinox.]