Altitude, in geography, is employed to denote the perpendicular height of any object, as the altitude of a mountain is its height above a given level, generally that of the sea.

Antarctic is a term applied, in opposition to Arctic, to the south pole, to the regions which encompass it, and to the circle by which they are supposed to be bounded at the distance of 23° 28' from the pole.

Antipodes is a term applied to those inhabitants of the terrestrial globe who live diametrically opposite to each other. It is derived from the circumstance of their being opposed feet to feet. As the antipodes are every way distant 180° from each other, they have equal latitudes, the one north and the other south. They have also the same seasons and length of day and night, but at contrary times, it being summer with one while it is winter with the other, and day with one while it is night with the other.

Archipelago is a term applied to any part of the sea containing numerous islands, particularly to that part of the Mediterranean situated between the coast of Asia Minor and European Turkey.

Basin is a term employed to denote those lower tracts of the earth's surface which are watered by large rivers, and into which the waters of the adjacent districts descend.

Bay is an arm or portion of the sea extending into the land; as the Bay of Biscay.

Cape is the termination of a promontory, or portion of land projecting into the sea or a lake; as the Cape of Good Hope.

Cardinal Points of the compass are the east, west, north, and south points of the horizon. These divide the horizon into four equal parts of 90° each.

Channel is the bed of a river. It is also applied to an arm of the sea; as the Bristol Channel.

Chart is a representation of the whole or part of the earth's surface, on a plane. The word is generally employed to denote maps of particular parts of the ocean, with the surrounding coasts, capes, bays, headlands, &c.

Circles of the Sphere are such as are supposed to be described either on the surface of the earth, or on the apparent sphere of the heavens. They are generally divided into two

classes, great and small; the former dividing the surface into two equal, the latter into two un equal parts. The great circles are the meridians, equator, ecliptic, and horizon; the small circles are parallels of latitude, &c.

Circles Polar are the two circles which encompass the polar regions, and are 23 degrees from the poles.

Climate is a term that expresses that particular combination of temperature and humidity to which any region or country is generally subject; or, in more general terms, it implies the actual state of the incumbent atmosphere.

Continent is a large tract of land, containing several contiguous countries, without any separation of its parts by the intervention of water.

Crater is the opening of a volcanic mountain from which the smoke and ignited matter issue.

Current is a body of water in motion, either on land or in the ocean.

Degree is the 360th part of a circle, or the 30th part of a sign. Each degree is divided into 60 equal parts or minutes, and each minute into 60 seconds.

Degree of latitude is that part of a meridian included between two points at which the difference in the elevation of any of the heavenly bodies, at the same instant, is equal to the 36th part of a circle.

Degree of longitude is the space between two meridians; that make an angle of one degree with each other at the pole. The degrees of longitude at different latitudes are unequal, and correspond to those of latitudes only at the equator. As the meridians approach each other till they meet at the poles, the degrees of longitude continually decrease until they become nothing at these points; hence a degree of longitude in any latitude is less than a degree on the equator.

Delta is a term frequently applied to those triangular spaces of low land between the different mouths, or near the estuaries of great rivers, which have been formed by the alluvial deposites of their waters. Thus the lower part of Egypt is usually called the Delta.

Equator is the great circle of the spheres which is everywhere equally distant from the poles. It is thus supposed to divide the surface

of the sphere into equal hemispheres, the one north, and the other south. All places situated on the equator have no latitude, and the days and nights are always of the same length. Longitude is also reckoned in degrees of the equator.

Equinoctial is a great circle of the heavens corresponding to the equator on the earth. It cuts the horizon of any place in the east and west points; and when the sun arrives at this circle, it rises and sets in these points, and the days and nights are then equal all over the globe. Declination is reckoned north and south from it. Equinoxes are the times when the sun enters the equinoctial points. This is about the 21st of March and the 23d of September; the former being the vernal, and the latter the autumnal equinox.

Evaporation is the conversion of water into vapor, which, by this process, is raised into the atmosphere, and, by a subsequent, but partial condensation, forms clouds. As a very considerable part of the earth's surface is covered with water, which is constantly evaporating and mixing with the atmosphere in the state of vapor, a precise determination of the rate of evaporation must be of great importance in physical geography. Accordingly, many experiments have been made by different philosophers to determine this point. From these we learn, that evaporation is confined entirely to the surface of the water, to which it is consequently proportional. Much more vapor, therefore, rises in maritime countries, or those interspersed with lakes, than in inland countries. More also rises during hot weather than cold; hence the quantity of evaporation depends upon the tempera-,

ture.

Geography is a description of the earth's surface; but the enlarged sense of the term includes a description, both of the inhabitants and productions of the terrestrial globe. Mathemat ical geography describes the figure and magnitude of the earth, its diurnal and annual revolutions, the cause of day and night, the succession of the seasons, the method of determining the positions of places on the earth's surface, and the comparison of linear measures, with the construction and use of maps. Physical geography delineates the principal features in the aspect of nature, by which the diversified regions of the globe are distinguished from each other, and portrays their agency on its inhabitants and productions. Civil or Political geography delineates the empires, kingdoms, and states, which occupy the surface of the earth, and exhibits the monuments of human industry and skill.

Glaciers is a name given to extensive fields of ice among the Alps Some of them clothe the elevated valleys on these lofty regions, while others envelope the sides and summits of the mountains; the former are denominated lower, and the latter upper glaciers. Those in

the valleys consist chiefly of solid ice. On the summits of the mountains they are composed of

snow.

Gravitation is the tendency which every particle of matter has to every other particle, at finite distances from each other. What is called gravitation with respect to the gravitating body, is called attraction, in reference to the body gravitated to. As all bodies, whatever may be their nature or magnitude, are only aggregated particles, gravitation takes place proportionally between them; and this power thus becomes the most universal agent of the material world. It is by it that bodies retain their forms; that the component parts of the earth, and the other planets, are not dissipated in the boundless regions of space; that terrestrial bodies, when unsupported, descend to the earth; that the planets and their satellites are retained in their orbits; and that the solar system itself maintains its place in the universe.

Harbor is a place of safety for ships.

Hemisphere is half the globe when it is supposed to be cut through the centre by the plane of one of its great circles. Thus the equator separates the northern and southern hemispheres; the meridian divides the eastern and western, and the horizon the upper and lower.

Horizon is the great circle of the sphere which divides its surface into the upper and lower hemisphere. In this sense it is called the rational horizon, and its plane passes through the centre of the earth.

Horizon sensible or visible is the small circle of the sphere which bounds the observer's view, and separates the visible from the invisible part of the globe.

Island is a portion of land wholly encompassed by water; as Great Britain or Ireland.

Isthmus is a narrow neck of land uniting two continents, or frequently a peninsula to a continent; as the Isthmus of Darien.

Lake is a portion of water, either entirely surrounded by land, or having no other outlet than a river, by which its contents are discharged. When a lake is very extensive, it obtains the denomination of sea; as the Caspian Sea.

Latitude is the distance of a place from the equator, and is estimated in degrees, minutes, &c., on the arc of the meridian passing through the place. Hence the latitude is either north or south, as the place is situated on the north or south side of the equator. The latitude of a place is always equal to the elevation of the pole above the horizon of that place.

League is the 20th part of a degree.

Longitude is the distance of a place eastward or westward from the first meridian, and is measured on an arc of the equator. It is by the combination of latitude and longitude that the situation of a place on the earth's surface is determined. As a degree of longitude is the 360th

part of a circle, it is necessarily greatest at the equator, and thence decreases to the poles, where it is nothing.

Map is a plane figure, representing either the whole or a part of the earth's surface; being a projection of the different countries, seas, mountains, coast, rivers, and other features of the globe, in their relative situations and proportions, as nearly as the nature of the problem will admit; for a globular surface cannot be correctly represented on a plane. Maps are therefore either general or particular, as they represent the whole or part of the earth.

The object to be obtained by the construction of a map must determine both its kind and size. If it is to be a general map, embracing a large portion of the earth's surface, the size must be large, and the projection employed such as will introduce but little alteration into the configurations of the countries it contains. Otherwise, the multiplicity of objects it must comprehend, and the alteration they would undergo, would render the representation altogether inadequate to the purpose. If, for instance, it is intended to construct a planisphere to be used in the study of astronomical geography, the stereographic projection on the plane of the horizon is best adapted. If a map of the world, for the purposes of physical geography be the object, the plane of the meridian is to be preferred, as this enables the geographer to present the old and new continents unbroken; the one being exhibited in the eastern, and the other in the western. The principal aim in this choice should be to exhibit the most faithful picture of the regions to be represented, upon the largest scale which the size of the map will admit, and consequently to exclude every thing foreign to the object in view. The top of a map is considered as north, the bottom south, the right hand east, and the left hand west.

Measure. The English statute mile consists of 5,280 feet, 1,760 yards, or 8 furlongs. The Russian werst is little more than 3 of a mile English. The Scotch and Irish mile is about 11 English. The Dutch, Spanish, and Polish, is about 31 English. The German is more than 4 English. The Swedish, Danish, and Hungarian, is from 5 to 6 English. The French common league is near 3 English. The English marine league is 3 English miles.

Meridian is a great circle, passing through the poles of the earth, and any given place on its surface. It therefore divides this surface into two hemispheres, the one being the eastern, and the other the western. The first meridian of any country is that from which its geographers, navigators, and astronomers commence their reckoning of longitude.

Minute of a degree, is the 60th part of a degree; this is subdivided into 60 seconds, and each of these again into thirds, when necessary.

Mountain is any considerable elevation on the

earth's surface. This name is applied both to detached heights, and connected groups or chains of these eminences.

North is that point of the horizon which is equally distant from the east and west points, and is diametrically opposed to the south.

Oasis is a term frequently applied to a fertile district amidst vast deserts of sand. Several of these occur in the sandy oceans of the African deserts; where the contrast was so great, as to induce the ancients to regard them as the Hesperides, or isles of the blessed.

Ocean is the term by which the vast mass of waters covering about two thirds of the earth's surface is designated. For the sake of perspicuity, geographers have supposed it to be divided into various parts, to which they have given particular names.

Pampas is a name given by the South Americans to the vast plains, which characterize their country.

Parallels of latitude are small circles of the sphere parallel to the equator.

Peninsula is any portion of land nearly surrounded by water. The term is generally applied to those parts which project into the ocean, and are joined to the main land by an isthmus.

Plateau is an elevated plain, or any high tableland terminated on all sides by declivities. The central parts of Asia, the middle regions of Spain, and the vast elevated lands on which Mexico is situated are all of this kind.

Polar circles are two small circles of the sphere which encompass the frigid zones, and are 23° 28' distant from the poles.

Pole is the point on the earth's surface where it is penetrated by the axis. As this axis terminates in two opposite points, the one is the north and the other the south pole, and each is 90° from the equator.

Prairie is a term applied to the unwooded tracts in the great valley of the Mississippi.

Promontory is a portion of land projecting into the sea, the end of which is generally called a cape.

River is a considerable body of water collected in the more elevated parts of the land, and descending into the lower, either discharging itself into another river or flowing into the sea. The courses of rivers always mark the greatest declivities of land over which they flow, and their magnitude is generally proportional to the height and distance of their sources.

Savanna is a term by which the vast extended plains in America are frequently denoted.

Sea, in its general extent, implies the whole of that vast body of water which covers a great part of the globe. It is, however, used to denote a particular part of this fluid, as the Baltic Sea, White Sea, &c.

Solar System is that assemblage of planets and satellites which have the sun for their com

mon centre, and which revolve about him, or rather about the centre of gravity of the system. Solstice is that point of time in which the sun is at his greatest distance from the equator, or when he is in those points of the ecliptic which touch the tropic of Cancer and Capricorn. There are, therefore, two solstices in the year, the one when the day is the longest, and the other when it is the shortest.

Sound is a small sea so shallow that it may sounded.

be

South is one of the cardinal points of the compass, and that which is opposed to north. Sphere, in geography, generally implies the relative positions of the equator and the horizon at any point on the earth's surface. Or, as the horizon varies with the position of the observer, it implies the relation of his situation with respect to the equator. As there can only be three distinct positions of these two circles, so there are said to be three kinds of spheres. When the equator and horizon intersect each other, at right angles, the position of the sphere is called a right sphere, which can be the case with those who live at the equator only. When the equator coincides with the horizon, and the parallels of latitude are parallel to it, the position is denominated a parallel sphere. This can only take place at the poles. In all other cases, the equator and horizon intersect each other obliquely, and then the position is called an oblique sphere.

Steppes are plains of great extent, and wholly destitute of the larger species of vegetables. This term is generally employed to denote

plains of this kind in Europe and Asia, while the words savanna and pampas signify the same thing in America.

Twilight is the faint light between perfect day and complete night. It is occasioned by the atmosphere refracting the rays of the sun after he has descended below the horizon. Its duration, therefore, varies not only with the latitude of the place, but also with the time of the year.

Vale signifies an extent of low country lying between ranges of higher ground. Vale and valley have distinct and appropriate meanings; the word valley is the diminutive of vale.

Volcano is a mountain which emits fire, smoke, or ignited matter. The number of active volcanoes on the globe is estimated at about 200.

Wind is a current of the atmosphere. There are three kinds of winds, permanent, periodical, and variable. The former blow between the tropics, and are called trade winds. Periodical winds, called monsoons, blow with great force in one direction nearly half the year, and towards the opposite point during the remainder. Variable winds blow from every point of the compass in the temperate regions of the globe.

Year is that portion of time which the sun occupies in passing through the 12 signs of the zodiac, or rather, which the earth requires to complete one revolution about the sun.

Zone is a division of the earth's surface made by two parallel circles. There are five of these zones, the torrid zone, the two frigid zones, and the two temperate zones.