tions of the Ecliptic are called by twelve different Names, viz.

1. v Aries, the Ram. 2. 8 Taurus, the Bull. 3. Gemini, the Twins. 4. Cancer, the Crab. 5. a Leo, the Lion. 6. m Virgo, the Virgin. 7. Libra, the Ballance. 8. Scorpio, the Scorpion. 9. ↑ Sagittarius, the Archer. 10. Capricornus,

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the Goat. 11. Aquarius, the Waterer. 12. x Pisces, the Fishes *.

These Names refer to the Stars, among which the Sun feems to pafs in his annual Circuit round the Earth. These are called the twelve Signs of the Zodiac +. If we would know to what Part of the Ecliptic the Sun is vertical any time of the Year, we may learn it from the four innermost Circles upon the wooden Horizon.

On the firft, or innermoft, are marked the Degrees of the twelve Signs.

The fecond has the Names, Characters, and Figures of those Signs.

The third is a Calendar of Months and Days, according to the New Style, anfwering to the Degrees of the twelve Signs by which is feen what Sign and Degree the Sun is in every Day throughout the Year.

*The Reader may fee a memorial Stanza for the Twelve Signs and their Order in Dr. Watts's Aftronomy, P. 9. or a fingle Latin Distich in the Gradus ad Parnafjum, on the word Zodiacus.

+ Concerning the Invention of thus dividing the Zodiac, the Reader may, perhaps, be pleafed with confulting the Sequel to the 4th lol. of Nature difplayed, Dialogue I.

B 4

The

The fourth is a Kalendar, in the fame manner, according to the Old Style.

N. B. Points at go Degrees diftant from any greater Circle, are called the Poles of that Circle. But when we fpeak of THE POLES, without mentioning the Circle to which they relate, we always mean the Poles of the Equator, which are the Extremities of the Axis of the Earth's diurnal Rotation. These are alfo called the Poles of the World.

Suppofe the Earth were cut in half at any greater Circle, it would produce a Plane, which is called the Plane of that Circle; as the Plane of the Equator; the Plane of the Meridian, &c.

A Map reprefenting the Surface of half the Globe, is faid to be projected upon the Plane of the Meridian, when the Pole of the Meridian is in its Center; and the Poles of the Equator are in the Periphery er Circumference. A Map projected upon the Plane of the Equator, has the Pole of the World in its Center. A Map projected upon the Plane of the Horizon of London, has London in the Middle of it.

N. B. Maps of the World are generally projected upon the Plane of the Meridian but Maps of the Stars upon the Plane of the Equator, or of the Ecliptic,

of

Of the Leffer Circles, viz. the Tropics, the Polar Circles, Parallels of Latitude, and the Horary Circle.

I, The TROPICS are two leffer Circles, each at 23 Degrees diftance from the Equator, to which they are parallel or equidiftant in all Parts. That on the North of the Equater is called the Tropic of Cancer, to which the Sun is vertical at the Summer Solstice, or longest Day of the Year to the Northern Hemisphere. That on the South is the Tropic of Capricorn, to which the Sun is vertical at our winter Solstice, which is the longest Day of the Year to the Southern Hemisphere.

II. The two POLAR CIRCLES are parallel to the Tropics, each at 23 Degrees distance from the Pole. The Northern is called the Arctic Circle, the Southern the Antarctic.

N. B. A Globe which does not confift of one continued Surface, but only of the greater and leffer Circles, made of Brafs, Wood, Pafteboard, &c. and put together in their natural order, is called an ArmilJary Sphere.

Other Circles drawn parallel to the Equator are called PARALLELS of LATITUDE: 99, or rather 89, fuch Circles drawn

I

drawn at equal Distances betwixt the Equator and the Pole, mark the Degrees of Latitude, which are number'd on the graduated Edge of the Brazen Meridian.

The Parallels of Latitude and Meridians are the Lines which are drawn upon Maps, croffing one another, and marking the Degrees of Latitude and Longitude.

III. The Brafs Circle with an Index fasten'd at the North Pole of the Globe, is called the HORARY CIRCLE; it is divided into twice 12 Hours, anfwering to the Time in which the Earth performs its diurnal Revolution: The upper 12 is for 12 at Noon, the lower for, 12 at Night,

CHA P. II.

Of the Divifions of the Earth.

TH

HE whole Surface of the terraqueous Globe admits of feveral different Divifions; as

FIRST, By the various Pofitions of the Globe in refpect to the Horizon.

1. Where the Poles of the Horizon are in the Equator, it is called a Right Sphere's because

because then the Equator, and all its Parallels, cut the Horizon at right Angles.. There the Poles of the World are in the Horizon; all the Stars rife and fet, and the Days and Nights are always equal.

2. Where the Poles of the World are the Poles of the Horizon, it is called a Parallel Sphere; the Equator, and all its Parallels, being then parallel to the Horizon. There the Sun, Moon, and Stars, appear to move round in Circles parallel to the Horizon; the fame Hemisphere of fixed Stars is always above the Horizon; and there is but one Day and one Night in a Year, each of fix Months.

3. When the Poles of the Horizon are any where betwixt the Equator and the Poles of the World, it is called an Oblique Sphere; the Equator, and its Parallels, there croffing the Horizon obliquely. There fome Stars never fet, others never rife; the Days and Nights are of different Lengths in different Seasons of the Year; and there one Pole of the World only is feen, which is elevated, more or lefs, according to the Obliquity of the Sphere. For the Elevation of the Pole, in any Place, is the Height of it above the Horizon, measured by Degrees on the Meridian; and it is always equal to the Latitude of the Place: So that the Pole being duly elevated for any Place, and the Place brought under the graduated

Edge