of Germany, Hungary, and Turkey, discharges itself into the Euxine Sea by feveral Channels. 27690

S. Of what Dimensions is the terreftrial Globe?

M. The Circumference of the terreftrial Globe Circumference is 360 Degrees, every Degree being 60 Geogra- of the Globe. phical Miles; fo that the whole Circuit is 21600 fuch Miles, and if the Diameter was a third Part of the Circumference, the Diameter would be 7200 Miles ; but the Dia- Diameter. meter is as 7 to 22, which makes it fomething

lefs than a third Part of the Circumference. If we reduce the Geographical Miles to English Miles, the Circumference of the Earth will be about 24,000 Miles, and the Diameter Soco.

S. What is the Earth founded upon ?

Circles on the

M. The terreftrial Globe refts upon nothing, but appears equally furrounded by the Heavens on every Side; for the better understanding whereof, it will be neceffary to obferve the feveral imaginary Circles defcribed on the artificial Globe, Plate 2. viz. 1. The Equator and Globe, the Circles parallel to it. 2. The firft Meridian and the rest of the meridional Lines. 3. The Zodiac, which includes the Ecliptic. 4. The Horizon. 5. The two Tropics. 6. The Artic and Antartic Circles. It is fuppofed alfo, that a Line paffes thro' the Center of the Globe, called its Axis, round which it moves every 24 Hours, the Ends of which Axis are called the Poles of the Earth, that in the North called the Artic or North Pole, from a Star in the Heavens oppofite to it, which forms Part of the Conftellation called the little Bear, and that in the South called the Antartic or South Pole, as diametrically oppofite to the other. S. Of what Ufe is that Circle denominated the Equator?

Equator.

M. By the Equator the Globe is divided into two equal Parts or Hemifpheres, and on this Circle are marked the Degrees of Longitude, from the first Meridian, either Eaft or Weft. The Parallel Circles are fo called from their running parallel to the Equator, of which there are nine in Number, inclufive between the Equator and cither Pole, ten Degrees diftant from each other, every Degree of Latitude being 60 geographical Miles, and every ten Degrees 600 fuch Miles. Confequently, it is 5400 Miles from the Equator to either Pole, which is one quarter of the Circumference of the Globe.

S. Of what Ufe is the firft Meridian?

M. The

Meridian.

M. The firft Meridian is reprefented by the brazen Circle in which the Globe moves, dividing it into the Eastern and Western Hemispheres, on which Circle are marked the Degrees of Latitude, which are counted Northward from the Equator to the North Pole, and Southward from the Equator to the South Pole.

Where the meridional Lines are 24 in Number, they are 15 Degrees or one Hour afunder; thofe who live under the meridian Line on the right Hand, that is, to the Eastward of the first Meridian, have the Sun one Hour before us; and those who live under the meridional Line on the left Hand, that is, Weft of us, have the Sun an Hour after us; and this shews what is meant by Eastern and Western Longitude. And as Longitude is nothing more than the Distance any Place is Eaft or West of the firft Meridian, fo Latitude is the Distance a Place is from the Equator North or South. If it be North of the Equator, it is called North Latitude, and if it be South of the Equator, it is called South Latitude.

Longitude.

Latitude.

S. Where is the firft Meridian ufually placed?

M. The first Meridian in the old Maps was placed either at Teneriff one of the Canary Isles, 17 Degrees Weft of London, or at Ferre another of the Canary Ifles, 19 Degrees Weft of London. But every Nation almoft at this Day places the first Meridian at their respective capital Cities in their feveral Maps. In Moll's, which are the correctest English Maps we have, London is made the first Meridian at one End of the Map, and Ferro at the other; Ferro being 19 Degrees Weft of London, as has been obferved already. And in thefe Maps the upper End is always the North, the lower End the South; the right Hand Eaft, and the left Hand Weft, the Degrees of Longitude being marked at the Top and Bottom of each Map, and the Degrees of Latitude on the Sides of the Map.

S. What is meant by the Zodiac?

M. The Zodiac is that Circle which cuts the

Zodiac. Equator obliquely, and is divided into twelve Signs, thro' which the Sun feems to pafs within the Space of 12 Months, each Sign containing 30 Degrees of Longitude.

The Ecliptic is a Line paffing thro' the middle of the Zodiac, and fhews the Sun's or rather the Earth's Path or Orbit, in which it moves annually.

S. Why do you fay the Earth's Orbit? Is it not the Sun that moves?

M. No,

M. No, but Geographers fpeak according to Appearances, the Appearance is the fame if the Earth moves from Weft to Eaft, as if the Sun moved from Eaft to West.

Horizon.

S. Which of the Circles is denominated the Horizon? M. The Horizon is the broad Circle in which the Globe ftands, dividing it into the upper and lower Hemispheres. The Place where any one ftands, is the Center of this Horizon and Hemifphere; the fenfible Horizon seems to touch the Surface of the Earth, and is the utmoft Limits of our Sight upon an extenfive Plain. The rational Horizon is fuppofed parallel to this, and to be extended to the Heavens.

The Poles of our Horizon are two imaginary Zenith, NaPoints in the Heavens, called the Zenith and Na- dir.

dir; the Zenith being the vertical Point directly over our Heads, and the Nadir that Point of the Heavens under our Feet, diametrically oppofite to the Zenith.

S. Are any Part of the Heavens under us?

M. As the Earth turns round upon its own Axis every 24 Hours, which makes Day and Night, that Part of the Heavens which was over our Heads at 12 at Noon, must of course be under our Feet at 12 at Night; but fpeaking properly, no Part of the Earth can be faid to be uppermoft or lowermoft. All the Inhabitants of the Earth feem to have the Earth under their Feet, and the Heavens over their Heads, and Ships fail with their Bottoms oppofite to each other.

S. Of what Ufe are the Circles denominated Tropics? M. The Tropics fhew how far the Sun or raTropics. ther the Earth proceeds North or South of the Equator every Year. The Tropic of Cancer furrounds the Globe 23 Degrees North of the Equator, and the Tropic of Capricorn 23 South of the Equator.

S. Where are the polar Circles placed?

M. The polar Circles are drawn 23 Degrees Polar Circles. diftant from each Pole, and 66 diftant from the

Equator.

S. What are thofe Divifions of the Earth called Zones?
M. The Earth is divided into five Zones, viz.

The torrid Zone, the two frigid Zones, and the

Zones.

two temperate Zones; and are denominated Zones, becaufe they encompass the Earth like a Girdle.

The torrid Zone lies between the two Tropics, Torrid Zene.

and is fo denominated from the exceffive Heat of

the Climate, the Sun paffing over it twice every Year.

The

The two frigid Zones lie within the polar Frigid Zones. Circles, and are fo called from the exceffive Cold within thofe Circles.

Temperate
Zones.

The Northern temperate Zone lies between the Tropic of Cancer, and the Artic Circle, and the Southern temperate Zone between the Tropic of Capricorn and the Antartic Circle.

S. What are we to understand by the Elevation of the Pole?

Elevation of the Pels.

M. The Elevation of the Pole is the Height of the Pole above the Horizon, and is always equal to the Latitude of any Place, as the South of England lies in 50 Degrees of North Latitude, fo the North Pole muft of courfe be elevated 50 Degrees above the Horizon there, for which Reafon the Latitude of a Place, and the Elevation of the Pole, are used promifcuously to exprefs the fame thing.

S. Pleafe to explain this by fome Inftances.

M. When you rectify the Globe, and bring any Place to the Zenith, the Horizon muft of course be 90 Degrees diftant from that Place, either North or South. Suppofe then the given Place lie in 50 Degrees of North Latitude, confequentÏy the given Place must be 40 Degrees diftant from the North Pole, and the Pole must be 50 Degrees above the Horizon of that Place, to make up the go Degrees on that Side. On the other hand, as the given Place lies 50 Degrees North of the Equator, your Horizon must extend to 40 Degrees of Southern Latitude, to make up the Complement of 90 Degrees on that Side. To explain this farther, fuppofe you bring Petersburgh to the Zenith, which lies in 60 Degrees North Latitude, and confequently is within 30 Degrees of the Pole, then there muft be 60 Degrees between the Pole and the Horizon to make up the Complement of 90 Degrees. And on the other hand, the Horizon of Petersburgh will extend but to 30 Degrees of Southern Latitude, that making up the Complement of 90 Degrees on that Side, for there will always be 90 Degrees between the Zenith and Horizon on every Side to form the Hemifphere.

S. Of what Ufe is the Hour Circle on the Globe?

Hour Circle.

The brazen horary Circle fixed on every Globe with an Index, fhews how many Hours, . and confequently how many Degrees any Place is Eaft or Weft of another Place; for as every 15 Degrees Eaft or Weft is an Hour, fo every Hour is 15 Degrees.

15 Degrees
one Hour Eaft
or Weft.

I

The

Quadrant of

Altitude.

The Quadrant of Altitude is a pliant brass Plate divided into 90 Degrees, one fourth of the Circumference of the Globe, by which the Dif ftances of Places may be found, and many useful Problems refolved.

S. How are the Inhabitants of the Earth diftinguished in regard to their respective Situations?

M. They are denominated either Periæci, Antæci, or Antipodes.

Periaci.

The Periæci are fituate under the fame Parallel, but oppofite Meridians: It is Midnight with one when it is Noon with the other, but the Length of their Days and their Seafons are the fame; thefe are found by the turning the horary Index 12 Hours, or turning the Globe half round.

Antaci

The Antæci are fituate under the fame Meridian, but oppofite Parallels; thefe have the Seafons oppofite to ours, and the fame Length of Days; but when their Days are longeft, ours are fhorteft. These are found by numbering as many Degrees on the oppofite Side of the Equator as we are on this.

Antipodes.

The Antipodes lie under oppofite Meridians, and oppofite Parallels; thefe have different Seafons, and their Noon-day is our Midnight, and their longeft Day our shortest: These are found by turning the horary Index 12 Hours from the given Place, or turning the Globe half round, and then counting as many Degrees on the oppofite Side of the Equator, as the given Place is on this.

Different

S. Are they diftinguished by any other Circumstances? M. The Inhabitants of the Earth are diftinguifhed by their different Shadows at Noon-day, Shadows. and are denominated either Amphifcii, Afcii, Hetérofcii, or Perifcii.

The Amphifcii inhabit the Torrid Zone, and have their Noon-day Shadows both North and

Amphifcii.

South: When the Sun is South of them, then their Shadows are North, and when the Sun is North of them their Shadows are South; these are alfo called Afcii, because the Sun is vertical twice every Year at Noon-day, and then they have no Shadow.

Afcii.

Heterofcii.

The Heterofcii, who inhabit the Temperate Zones, have their Shadows always one Way at Noon-day. In the Northern temperate Zone their Shadows are always North; and in the Southern temperate Zone, their Shadows are always South at Noon-day.

The