SECT. II.
Geographical Definitions.
Of the Situations of Places upon the Earth; of the different Situations of its Inhabitants; of Zones and Climates.
The situations of places upon the Earth, are determined by their Latitude and Longitude.
Latitude.
1. The Latitude of any place (upon the Earth) is its nearest distance, either North or South from the Equator; and if the place be in the (Northern/Southern) hemisphere, it is accordingly called (North/South) Latitude; and is measured by an arch of the meridian intercepted betwixt the zenith of the said place, and the equator. And all places that lie on the same side, and at the same distance from the equator, are said to be in the same parallel of latitude: the parallels in Geography, being the same with the parallels of declination in Astronomy.
From this definition arise the following Corollaries.
(1.) That no place can have above 90 degrees of latitude, either North or South.
(2.) Those places that lie under the equinoctial (or thro’ which the equator passes) have no latitude, it being from thence that the calculation of latitudes is counted; and those places that lie under the Poles have the greatest latitude, those points being at the greatest distance from the equator.
(3.) The latitude of any place is always equal to the elevation of the Pole in the same place above the horizon; and is therefore often expressed by the Pole’s height, or elevation of the Pole; the reason of which is, because from the equator to the Pole there is always the distance of 90 degrees, and from the zenith to the horizon the same number of degrees, each of these including the distance from the zenith to the Pole: That distance therefore being taken away from both, will leave the distance from the zenith to the equator, (which is the latitude) equal to the distance of the Pole to the horizon.
(4.) The elevation of the equator in any place is always equal to the complement of the latitude of the same place.
(5.) A ship sailed directly (towards/from) the equator (lessens/augments) her latitude, (or (depresses/raises) the Pole) just so much as is her distance sailed.
Difference of Latitude.
2. Difference of latitude is the nearest distance betwixt any two parallels of latitude, shewing how far the one is to the Northward or Southward of the other, which can never exceed 180 degrees. And when the two places are in the same hemisphere (or on the same side of the equator) the lesser latitude subtracted from the greater, and when they are on different sides of the equator, the two latitudes added, gives the difference of latitude.
Longitude.
3. The Longitude of any place (upon the Earth) is an arch of the equator, contained betwixt the meridian of the given place, and some fixed or known meridian; or, it is equal to the angle formed by the two meridians, which properly can never exceed 180 degrees, tho’ sometimes the Longitude is counted Easterly quite round the globe.
Since the meridians are all moveable, and not one that can be fixed in the heavens, (as the equinoctial circle is fixed, from whence the latitudes of all places are determined to be so much either North or South) the longitudes of places cannot so well be fixed from any other meridian, but every Geographer is at his liberty to make which he pleases his first meridian, from whence to calculate the longitudes of other places. Hence it is that geographers of different nations reckon their longitudes from different meridians, commonly choosing the meridian passing through the metropolis of their own country for their first: Thus, the English geographers generally make the meridian of London to be their first, the French that of Paris, and the Dutch that of Amsterdam, &c. and mariners generally reckon the longitude from the last known land they saw. This arbitrary way of reckoning the longitude from different places, makes it necessary, whenever we express the longitude of any place, that the place from whence it is counted be also expressed.
From the preceding definitions arise the following corollaries:
1. If a body should steer directly North, or directly South, quite round the globe, he’ll continually change his latitude; and pass through the two Poles of the world, without deviating the least from the meridian of the place he departed from; and consequently on his return will not differ in his account of time from the people residing in the said place.
2. If a body should steer round the globe either due East, or due West, he’ll continually change his longitude, but will go quite round without altering his latitude; and if his course should be due East, he’ll gain a day compleatly in his reckoning, or reckon one day more than the inhabitants of the place from whence he departed; or if his course had been West, he would have lost one day, or reckon one less.
The reason of which is evident; for admitting our traveller steers due East; so many miles in one day as to make his difference of longitude equivalent to a quarter of an hour of time, it is evident that the next day the Sun will rise to him a quarter of an hour sooner than to the inhabitants of the place from whence he departed; and so daily, in proportion to the rate he travels, which in going quite round, will make up one natural day. In like manner, if he steers due West after the same rate, he’ll lengthen each day a quarter of an hour, and consequently the Sun will rise to him so much later every day; by which means, in going quite round, he’ll lose one day compleat in his reckoning. From whence it follows,
3. If two bodies should set out from the same place, one steering East, and the other West, and so continue their courses quite round, until they arrive at the place from whence they set out, they’ll differ two days in their reckoning at the time of their return.
4. If a body should steer upon an oblique course (or any where betwixt the meridian and the East or West points) he’ll continually change both latitude and longitude, and that more or less, according to the course he steers; and if he should go quite round the globe, he’ll differ in his account of time, as by the second Corol.
5. The people residing in the Easternmost of any two places, will reckon their time so much the sooner than those who live in the other place, according to the difference of longitude betwixt the two places, allowing one hour for every 15 degrees, &c. and the contrary.
II. Of Zones and Climates, &c.
Zones, Torrid, Temperate, and Frigid.
4. Zones are large tracts of the surface of the Earth, distinguished by the tropics and polar circles, being five in number; viz. one Torrid, two Temperate and two Frigid.
The Torrid, or Burning Zone, is all the space comprehended between the two tropics; the ancients imagined this tract of the Earth to be uninhabitable, because of the excessive heat, it being so near the Sun. All the inhabitants of the torrid zone have the Sun in their zenith, or exactly over their heads twice in every year; excepting those who live exactly under the two tropics, where the Sun comes to their zenith only once in a year.
The two Temperate Zones lie on either side of the globe, between the tropics and the polar circles.
The two Frigid Zones are those spaces upon the globe that are included between the two polar circles.
Amphiscians.
Ascians.
The inhabitants of the Earth are also distinguished by the diversity of their Shadows. Those who live in the torrid zone, are called Amphiscians, because their noon-shadow is cast different ways, according as the Sun is to the northward or southward of their zenith; but when the Sun is in their zenith, they are called Ascians.
Heteroscians.
Ascians Heteroscians.
Periscians.
The inhabitants of the temperate zones, are called Heteroscians, because their noon-shadow is always cast the same way: But those who live under the tropics are called Ascians Heteroscians; those who live in the frigid zones are called Periscians, because sometimes their shadow is cast round about them.
These hard names are only Greek words, importing how the Sun casts the shadow of the several inhabitants of the Earth; which would be a too trifling distinction to be made here, was it not for the sake of complying with custom.
The inhabitants of the Earth are also distinguished into three sorts, in respect to their relative situation to one another, and these are called the Periœci, Antœci, and Antipodes.
Periœci.
5. The Periœci are those who live under opposite points of the same parallel of latitude. They have their seasons of the year at the same time, and their days and nights always of the same length with one another, but the one’s Noon is the other’s Midnight; and when the Sun is in the equinoctial, he rises with the one, when he sets with the other. Those who live under the Poles have no Periœci.
Antœci.
6. The Antœci live under the same meridian, and in the same latitude, but on different sides of the equator; their Seasons of the year are contrary, and the days of the one are equal to the nights of the other, but the hour of the day and night is the same with both; and when the Sun is in the equinoctial, he rises and sets to both exactly at the same time. Those who live under the equator have no Antœci.
Antipodes.
7. The Antipodes are those who live diametrically opposite to one another, standing, as it were, exactly feet to feet: Their days and nights, summer and winter, are at direct contrary times.
The surface of the Earth is by some distinguished into Climates.
Climates.
8. A Climate is a tract of the surface of the Earth, included between two such parallels of latitude, that the length of the longest day in the one exceeds that in the other by half an hour.
The whole surface of the Earth is considered, as being divided into 60 climates, viz. from the equator to each of the polar circles 24, arising from the difference of ½ hour in the length of their longest days; and from the polar circles to the Poles themselves, are six, arising from the difference of an entire month, the Sun being seen in the first of these a whole month without setting; in the second two; and in the third, three months, &c. These climates continually decrease in breadth, the farther they are from the equator. How they are framed, viz. the parallel of latitude in which they end (that being likewise the beginning of the next) with the respective breadth of each of them, is shewed in the following table:
A TABLE of the Climates.
| Climates | Longest | Latitude. | Breadth | ||
|---|---|---|---|---|---|
| Day. | D. | M. | D. | M. | |
| 1 | 12½ | 8 | 25 | 8 | 25 |
| 2 | 13 | 16 | 25 | 8 | 00 |
| 3 | 13½ | 23 | 50 | 7 | 25 |
| 4 | 14 | 30 | 25 | 6 | 30 |
| 5 | 14½ | 36 | 28 | 6 | 8 |
| 6 | 15 | 41 | 22 | 4 | 54 |
| 7 | 15½ | 45 | 29 | 4 | 7 |
| 8 | 16 | 49 | 1 | 3 | 32 |
| 9 | 16½ | 51 | 58 | 2 | 57 |
| 10 | 17 | 54 | 27 | 2 | 29 |
| 11 | 17½ | 56 | 37 | 2 | 10 |
| 12 | 18 | 58 | 29 | 1 | 52 |
| 13 | 18½ | 59 | 58 | 1 | 29 |
| 14 | 19 | 61 | 18 | 1 | 20 |
| 15 | 19½ | 62 | 25 | 1 | 7 |
| 16 | 20 | 63 | 22 | 0 | 57 |
| 17 | 20½ | 64 | 6 | 0 | 44 |
| 18 | 21 | 64 | 49 | 0 | 43 |
| 19 | 21½ | 65 | 21 | 0 | 32 |
| 20 | 22 | 65 | 47 | 0 | 26 |
| 21 | 22½ | 66 | 6 | 0 | 19 |
| 22 | 23 | 66 | 20 | 0 | 14 |
| 23 | 23½ | 66 | 28 | 0 | 8 |
| 24 | 24 | 66 | 31 | 0 | 3 |
| Length of Days. | Latitude. | |
|---|---|---|
| Months. | D. | M. |
| 1 | 67 | 21 |
| 2 | 69 | 48 |
| 3 | 73 | 37 |
| 4 | 78 | 30 |
| 5 | 84 | 5 |
| 6 | 00 | 00 |
III. Of the Poetical rising and setting of the Stars.
Cosmical, Acronical, and Heliacal rising and setting.
The ancient Poets make frequent mention of the Stars rising and setting, either Cosmically, Acronically, or Heliacally; whence these distinctions are called Poetical.
A Star is said to rise or set Cosmically, when it rises or sets at Sun-rising; and when it rises or sets at Sun-setting, it is said to rise or set Acronically. A Star rises Heliacally, when first it becomes visible, after it had been so near the Sun as to be hid by the splendor of his rays: And a Star is said to set Heliacally, when it is first immersed, or hid by the Sun’s rays.
The Fixed Stars, and the three superior Planets, Mars, Jupiter, and Saturn, rise Heliacally in the morning; but the Moon rises Heliacally in the evening, because the Sun is swifter than the superior Planets, and slower than the Moon.
IV. Of the surface of the Earth, considered as it is composed of Land and Water.
The Earth consists naturally of two parts, Land and Water, and therefore it is called the Terraqueous Globe. Each of these elements is subdivided into various forms and parts, which accordingly are distinguished by different names.
I. Of the Land.
The land is distinguished into Continents, Islands, Peninsula’s, Isthmus’s, Promontories, Mountains, or Coasts.
Continent.
Main Land.
9. A Continent is a large quantity of land, in which many great countries are joined together, without being separated from each other by the sea: such are Europe, Asia, Africa, and the vast continent of America; which four are the principal divisions of the Earth. A continent is sometimes called the Main Land.
Island.
10. An Island is a country, or portion of land, environed round with water: such are Great-Britain and Ireland; Sardinia, Sicily, &c. in the Mediterranean Sea; the Isles of Wight, Anglesey, &c. near England. Also a small part of dry land, in the midst of a river, is called an island, when compared to a lesser, is called the continent; as if we compare the Isle of Wight to England, the latter may be properly called the continent.
Peninsula.
11. A Peninsula is a part of land almost environed with water, save one narrow neck adjoining it to the continent; or which is almost an island: such is Denmark joining to Germany; also Africa is properly a large peninsula joining to Asia.
Isthmus.
12. An Isthmus is a narrow neck of land joining a peninsula to the continent; as the Isthmus of Sues, which joins Africa to Asia, that of Panama, joining North and South America, &c.
Promontory.
Mountain.
13. A Promontory is a high part of land stretching out into the sea, and is often called a Cape or Headland: such is the Cape of Good Hope in the South of Africa; Cape Finistre on the West of Spain; also the Lizard Point, and the Land’s End, are two Capes or Headlands on the West of England. A Mountain is a high part of land in the midst of a country, over topping the adjacent parts.
A Coast or Shore.
Inland.
14. A Coast or Shore is that part of land which borders upon the sea, whether it be in islands or a continent: And that part of the land which is far distant from the sea, is called the Inland Country. These are the usual distinctions of the land.
The Water is distinguished into Oceans, Seas, Lakes, Gulfs, Straits, and Rivers.
The Ocean, or Main Sea.
15. The Ocean, or Main Sea, is a vast spreading collection of water, not divided or separated by lands running between; such is the Atlantic or Western Ocean; between Europe and America; the Pacific Ocean, or South Sea, &c.
Note, Those parts of the ocean which border upon the land, are called by various names, according to those of the adjacent countries; as, the British Sea, the Irish Sea, the French and Spanish Sea.
A Lake.
16. A Lake is a collection of deep standing water, inclosed all round with land, and not having any visible and open communication with the sea: But when this lake is very large, it is commonly called a sea; as the Caspian Sea in Asia, &c.
A Gulf.
Creek or Haven.
17. A Gulf is a part of the sea almost encompassed with land, or that which runs up a great way into the land; as, the Gulf of Venice, &c. But if it be very large, ’tis rather called an Inland Sea; as the Baltic Sea, the Mediterranean Sea, the Red Sea, or the Arabian Gulf, &c. And a small part of sea thus environed with land is usually called a Bay. If it be but a very small Part, or, as it were, a small arm of the sea, that runs but a few miles between the land, it is called a Creek or Haven.
A Strait.
18. A Strait is a narrow passage lying between two shores, whereby two seas are joined together; as, the Straits of Dover, between the British Channel and the German Sea; the Straits of Gibralter, between the Atlantic and the Mediterranean Sea. The Mediterranean itself is also sometimes called the Straits.
These are all the necessary terms commonly used in Geography. The names of the several countries and seas, and all the principal divisions of the Earth, the reader will find expressed upon the Terrestrial Globes. To give a tolerable account of the produce of each country, the genius of the people, their political institutions, &c. is properly a particular subject of itself, and quite foreign to our design. We shall next proceed to the use of the Globes; but first it may not be amiss to take a short review of their appurtenances.
Those circles of the sphere that are fixed, are (as has been already said) drawn upon the Globes themselves; those that are moveable, are supplied by the Brass Meridian, the Wooden Horizon, and the Quadrant of Altitude.
Brass Meridian.
1. That side of the Brazen Meridian, which is divided into degrees, represents the true Meridian; this side is commonly turned towards the East, and ’tis usual to place the globe so before you, that the North be to the right hand, and the South to the left. The meridian is divided into 4 quadrants, each being 90 degrees, two of which are numbered from that part of the equinoctial, which is above the horizon, towards each of the Poles; the other two quadrants are numbered from the Poles towards the equator. The reason why two quadrants of the meridian are numbered from the equator, and the other two from the Poles, is because the former of these two serve to shew the distance of any point on the globe from the equator, and the other to elevate the globe to the latitude of the place.
Wooden Horizon.
2. The upper side of the wooden frame called the Wooden Horizon; represents the true horizon; the circles drawn upon this plane have been already described; we may observe, that the first point of ♈ is the East, and the opposite being the first point of ♎ is the West, the meridian passing through the North and South points.
Quadrant of Altitude.
3. The Quadrant of Altitude is a flexible plate of thin brass, having a nut and screw at one end, to be fastened to the meridian of either globe, as occasion requires. The edge of this quadrant which has the graduations upon it, called the fiducial edge, is that which is always meant whenever we make mention of the quadrant of altitude.
Hour Circle.
4. The Horary or Hour Circle, is divided into twice twelve hours, the two XII’s coinciding with the meridian; the uppermost XII is that at Noon, and the lowermost towards the horizon is XII at Night. The hours on the East side of the meridian are the Morning Hours, and those on the West side the Hours after Noon. The axis of the globe carries round the Hand or Index which points the hour, and passes through the center of the hour circle.
The things above described are common to both globes; but there are some others which are peculiar or proper to one sort of globe. The two Colures, and the Circles of Latitude from the ecliptic, belong only to the Celestial Globes; also the ecliptic itself does properly belong only to this globe, tho’ it is always drawn on the Terrestrial, for the sake of those that might not have the other globe by them. The equinoctial on the celestial globe is always numbered into 360 degrees, beginning at the equinoctial point ♈; but on the terrestrial, it is arbitrary, where these numbers commence, according to the meridian of what place you intend for your first; and the degrees may be counted either quite round to 360, or both ways, ’till they meet in the opposite part of the meridian, at 180.
