THE Breadth of the Torrid Zone is 47 Degr i. e. 23 Degr. 30 Min. on each fide of the Equator, The Breadth of each Temperate Zone is 86 Degr. and of both Frigid Zones 27 Degr. which Degrees, if turned to Miles, counting each Degree 15 German Miles, the Breadth of the Torrid Zone will be 705 Miles. And one of the Temperate 645, and one of Frigid 352. And the Superficies of each is known by this Proportion from Geometry; as the Sine of 90 Degr. 1000000 is to the Sine of 23 Degr. 30 Min. viz. 39875; fo is half the Superficies of the Earth found in Chap. 4. to be 463909a fquare Miles to the Superficies of half the Torrid Zone, i. e. 1849837 fquare Miles; and therefore the Superficies of the whole Torrid Zone is 3699674 Miles.

THEN as the whole Sine 100000 to the Difference of the Sines of 23 Degr. 30 Min. and 66 Degr. 30 Min. 51831; fo is the half Superficies of the Earth or 4639090 fquare Miles, to the Superficies of one of the Temperate Zones 2404487 fquare Miles. If therefore you fubftract the Superficies of half the Torrid Zone, and that of the Temperate Zone, from half the Superficies of the Earth, there remains the Superficies of one of the Frigid Zones 384766 fquare Miles. Some Aftronomers are of Opinion, that the Declination of the Ecliptic is not always the fame; and therefore the Bignefs of the Zones is not always the fame; but the Difference is fmall and Tycha doubted if there was any. We need not mind it here.

WE might have treated of the different Seafons in different Places; but because there are some things in the following Chapter that will help us to pake a better Judgment thereof, I thought it beft to defer it.

CHAR

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CHAP. XXV.

Of the Length of the Day in different Places of the Earth, and the Divifion of the Earth into Cli mates, which arifes from thence.

PROPOSITION I.

The Days and Nights are of the fame Length twice in the Year in all Places.

TH

HESE Days are when the Sun is in the Equator, i. e. in the first of Aries and Libra, on the twenty firft of March, and twenty firft of September, according to the Gregorian Calendar; which Days have twelve Hours Day, and twelve Hours Night, in all Places, counting the time the Sun is above the Horizon for a Day.

TAKE any Place on the Globe, and elevate it according to its Latitude, or bring the Place to the Zenith; then bring the Sun's Place to the Horizon in the Eaft, and the Index of the horary Circle to twelve, and turn the Globe; you will find it will describe twelve Hours while the Sun's Place is going to the Horizon in the Weft: it appears. further from the Horizon's cutting the Equator into two equal Parts. We might fhow it the fame way, whatever Place of the Earth be chofen. And the two Poles do thofe two Days neither rife nor fet, and they have there Night and Day at once; in other Places it turns from Day to Night in an Inftant, but there they laft together for a whole Revolution; the one half of the Sun being above,

and

and the other below the Horizon. On the twenty firft of March begins a Day of fix Months, and on the twenty first of September a Night as long; and we may fay, 'tis both Day and Night for twelve Hours at the Pole. There are other things peculiar to that Place.

1. THE Sun only rifes and fets there once in a Year, it rifes the twenty firft of March, and fets the twenty first of September.

2. THEY have no Mid-day and Mid-night at a fet Time; their Mid-day being at all Times for fix Months, and the other fix 'tis always Midnight.

3. NO fix'd Stars rife, and none fet, but fome are always under, others always above; the former of which being never feen by the Inhabitants, if any there, which is not likely; the latter always feen for fix Months if the Weather be clear when the Sun is under the Horizon.

4. THE Stars and the Sun keep almost the fame Altitude all Day.

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5. NO Wind can be called there, northerly; they being all from the South; and in the other, the South Pole, they are all northerly.

6. IF the Sun and Stars move not according to Copernicus, but the Earth, and the Eye, be a Point placed in the Pole, all the Stars, and the Sun and Moon, would appear immoveable in the fame Place,

PROPOSITION II.

In Places under the Equator the Days and Nights are always equal and at the Poles there is but one Day and Night in the Year; tho' the Day at the North Pole is longer than at the South Pole.

TAKE

SECT. VI. TAKE any Place on the Globe under the Equator, and any Day of the Year, and mark the Sun's Place that Day, and bring the Place to the Zenith, the Poles being in the Horizon; and it will appear, that that Place, in a Revolution of the Globe, will be as long above as under the Horizon, fuppofing it's apparent Motion equal, as indeed it is. And as to the other Part of the Propofition; bring the Pole to the Zenith, the one half of the Ecliptic will be above, the other below the Horizon, but the Sun will be longer above than below, for it really moves in an Ellipfis whofe Focus is out of it's Center; or the Earth does fo, which makes the fame Appearance: there are one hundred eighty feven Days it continues above, and one hundred feventy eight below; which makes the Day about nine Days longer than the Night.

PROPOSITION II.

There are no Days equal except two in the Places between the Equator and the Pole.

TAKE any Place, and elevate the Pole according to it's Latitude, and taking any Day, except thofe two of the Equinoxes, and mark the Sun's Place in the Ecliptic for that Day; turn the Globe and you will fee the Mark will be longer above than below the Horizon, if the Day be between the twenty firft of March, and twenty first of September; but if not, it will be longer below the Horizon: and the Difference will be the greater, the further the Sun is from the Equator.

OR bringing the Sun's Place to the Eaft Horizon, and the Hour Hand to twelve, you will fee, in turning the Globe, the Hours of the Day 'till the Sun fet in the Weft; and it's Continuance under the Horizon.

PRO

PROPOSITION IV.

A Place being given, and it's Latitude, to find the Length of the Day at any

Time.

FIND the Sun's Place at that time in the Ecliptic, and elevate the Pole to the Latitude of the Place, bring the Sun's Place to the Eaft Horizon, and the Hour Hand to twelve; you will fee how many Hours the Sun's Place will take to come to the Weft Horizon; and substract them from twenty four, and you have the Length of the Day.

PROPOSITION V.

In all Places between the Equator and North Pole, the Day is longest when the Sun is in Cancer, and fhorteft when in Capricorn; but in thofe Places between the Equator, and the South Pole the contrary happens; that is, when the Sun is in Cancer, the Days are forteft, and when in Capricorn longest.

TAKE a Place at Pleafure, and elevate the Pole according to it's Latitude; find, by the preceding Propofition, the Number of Hours in the Day, when the Sun is in the first of Cancer; and find alfo the Number of Hours for another Part of the Ecliptic, which will be found lefs, whatever other Part of the Ecliptic be taken.

THE fame way it may be fhown, that the Day is shortest when the Sun is in the first of Capricorn. And the fame Method may be taken when the Sum is on the other Side of the Equator.

COROL