I.ET. XI. AND VICISSITUDES OF THE SEASONS. lyr

darkness, and the revolution of the globe canbring no part of it into the light.

If the earth were to continue in the fame partof its orbit, the fun would never set to the in-habitants of the north frigid zone, nor rife tothose of the south frigid zone. At the equatorit would always be equal day and night; and atplaces more distant from the equator, towardsthe arctic circle, they would have their dayslonger than their nights, whilst those on thesouth side of the equator would have their nightslonger than their days; so that in this cafe,there would be continual summer on the northside of the equator, and continual winter on thesouth side of it.

But as the globe turns round its axis, moveyour hand slowly forwards, so as to carry itfrom H towards E, and the boundary of lightand darkness will then approach towards thenorth pole, and recede from the south pole; thenorthern places will go through less and less ofthe light, and the southern places through moreand more of it; which shews how the northerndays decrease in length, and the southern daysincrease, whilst the globe proceeds from H to E.

When the globe is at E, it is at a mean situa-tion between the lowest and highest parts of itsorbit; the candle is directly over the equator;the boundary of light and darkness just reachesto both the poles ; and all places on the globe