XIII. To find all those inhabitants to whom the sun is this môment rising or setting, in their meridians, or midnight. Find the sun's place in the ecliptic, and raise the pole as much above the horizon as the sun that day declines from the equator; then bring the place where the sun is verti cal at that hour, to the brass meridian; so will it then be in the zenith, or centre of the horizon. Now see what countries lie on the western edge of the horizon, for to them the sun is rising; to those on the eastern side he is setting; to those under the upper part of the meridian, it is noonday; and to those under the lower part of it, it is midnight. Thus, on the 10th of April at four o'clock in the morn ing, at Charlestown, (Mass.) It is sun-rise at Sun-setting at Mid day, or noon, at Midnight at MAPS. Brazil, South-America, Isles and Kamtschatka, A Map is a representation of the earth's surface, or some part of it, delineated on a plane, according to the laws of perspective, and contains such circles, or parts of circles, as the size and situation of the place delineated will admit. The top of a map represents the north, the bottom, the south; the right hand side, the east, and the left hand, the west. From the top to the bottom, are drawn merid ians or lines of longitude: and from side to side, parallels of latitude. The outermost of the meridians and par. allels are marked with degrees, by means of which, and a scale of miles usually placed in the corner of a map, the situations and distances of places may be found, as on the artificial globe. Rivers are described in maps by black lines, and are wider toward the mouth, than toward the head or s ring. Mountains are represented as on a picture, by a sort of cloud; forests and woods by a kind of shrub; bogs and morasses, by shades; sands and shallows, by small dots roads, usually by double lines; and towns, by an 0 or a small house. Near harbors, the depth of water is some. times expressed by figures, representing fathoms NATURAL DIVISIONS OF THE EARTH'S SURFACE. The first grand division of the earth is into Land and Water. Divisions of Land. A great extent of land, not entirely separated by water, is called a cONTINENT. There are commonly reckoned two Continents, called the Eastern, comprehending Asia, Europe and Africa; and the Western, including North and South America. New Hol land has sometimes been dignified with the name of continent; but is usually classed by geographers among the islands of the Pacific ocean. A tract of land, entirely surrounded by water, is an IsLAND. Tracts of land, almost encircled by water, as Boston, are PENINSULAS. Necks of land, which join peninsuIas to a main land, are ISTHMUSES. Land projecting far into the sea is a PROMONTORY. The end or point of a promontory is a CAFE. When land rises to a very great height above the level country, it is a MOUNTAIN. When this high land extends unevenly to a great length, it is called a chain or range of Mountains. When a mountain emits flames and sulphur, &c. it is a VOLCANO. The side of a steep mountain is a PRECIPICE. When land rises to a small height it is called a Hill. The spaces between hills are called DALES; and very of ten, and perhaps commonly in America, VALES, OF VAL LEYS. Divisions of Water. The waters, that cover so great a portion of the surface of the globe, are collectively called the OCEAN, and sometimes the SEA. Different and extensive portions of these great waters have obtained the name of OCEANS. These are the At lantic, the Indian, the Pacific, the Southern and the Arctic or Frozen Ocean. The two former are each 3000 miles across; the Pacific 10,000. The extent of the others is not known. Large collections of water that are nearly enclosed by land are called SEAS; and smaller collections of this kind are called SOUNDS, BAYS, or GULFS; as the Mediterranean Sta, Long Island Sound, Chesapeak Bay, the Gulf of Mexico. A narrow communication between a sea or bay, and the ocean, or between two seas or lakes, is a STRAIT, MOUTH, ENTRANCE, or INLET. A great body of fresh water, surrounded by land, or communicating with the ocean only by a long river, is called a LAKE. Smaller collections of fresh water are called PONDS. The fountains of water at the heads of rivers, brooks, or rivulets, and from which wells are supplied, are called SPRINGS. When the fountains are warmer than usual, or are impregnated with fixed air, salts, sulphur, metals, and other mineral substances, they are called MEDICINAL, or MINERAL SPRINGS. Streams or bodies of running water, according to their magnitude are called RIVERS, BROOKS or RIVULETS. CREEKS are narrow branches of the ocean, indenting and sometimes insulating the sea coast. Some branches of rivers are sometimes called Creeks. When a large body of water tumbles over a precipice, it is called a CATA RACT or FALLS, as the Falls of Niagara. If the quantity of water be small, it is a CASCADE. Standing water, in which earth, with grass or shrubs upon it, appears in different parts ;-and low, sunken grounds, full of trees and mire, are salled MORASSES, BOGS, FENS, but more commonly, among us, SWAMP. COMPONENT PARTS OF THE EARTH. The Earth is composed of land and water, and is therefore called terraqueous. It is ascertained, from recent discoveries, that the waters contained in the concavities of the globe, cover at least two thirds of its surface. The earth below its surface is composed of various substances, collectively called FosSILS. All substances dug out of mines of whatever kind, such as metals, coal, sulphur, ochre, &c. are called MINERALS. Such of the minerals as can be malleated or beaten out with a hammer, are called METALS. These are common. ly reckoned seven in number which are reckoned according to their weight in the following order :-1. Platina, a white metal, newly discovered in the gold mines of South-America, in many of its properties resembling gold. 2. Gold. 3 Lead. 4. Silver. 5. Copper. 6. Iron. 7. Tin. To. these should be added Quicksilver. Three of these, Plati na, Gold, and Silver, (of which Platina is much the heavi est) are called perfect metals, because they remain longest unchanged by fire. The other four are called imperfect metals, because they may be destroyed, or changed into earth by fire. By a chymical operation on Iron, Steel is produced. A mixture of Tin and Lead, in certain portions, forms the compound called PEWTER. The best chymists divide bodies, or the objects of chymistry, into salts, earths, inflammable substances, metals and waters. The effects of heat and mixture on these bodies constitute what is called The Science of Chymistry VOLCANOES. VOLCANOES are burning mountains, which include in their bowels sulphur, bitumen, and other combustible matters, the effect of which, when kindled into a flame, is more violent than that of gunpowder, or any thing yet known in nature. As the explosive force of gunpowder arises from the conversion of water into air, that which takes place in volcanoes is undoubtedly from the same cause. Volcanoes may be compared to huge cannon. From their mouths, some of which are a mile and a half wide, are vomited forth dreadful volumes of smoke and flame; torrents of bitumen, sulphur, and melted metals; clouds of cinders and stones; and sometimes rocks of enormous bulk are thrown to a great distance. In the great eruption of Mount Vesuvius, in 1779, a stream of Lava* of an im Lava is the melted matter, which issues from Volcanoes. mense magnitude, is said to have been thrown to the height of at least 10,000 feet above the top of the mountain. The quantity of lava thrown out sometimes is so great as to enter cities, forests, and the ocean, in large rivers. Fields have been covered with it, 100 and even 200 feet in thickness. The force of the explosion has been so great as to shake the earth, agitate the sea, and even mountains, and overthrow the most solid edifices. There are three noted volcanoes, viz. Monnt Hecla, in Iceland; Mount Etna, in Sicily; Mount Vesuvius, in Naples. There are many others of less note in Asia, Africa, and America. EARTHQUAKES. There are two kinds of EARTHQUAKES; One is caused by the action of subterraneous fires, and the explosion of volcanoes, which are felt only at small distances, and at the time when volcanoes act, or just before they open, The other is supposed to be produced by immense quantities of inflammable air, contained and compressed in the caverns and crevices of the earth, which being greatly rarified by internal fires, and finding no outlet, forces a passage through all obstructions. Earthquakes are usually preceded by a general stillness in the air; the sea swells and makes a great noise; the fountains are troubled and send forth muddy water; the birds seem frightened, as if sensible of the approaching calamity. The shock comes on with a rumbling noise, like that of carriages on frozen ground, or thunder; the ground heaves and rolls or rocks from side to side. The shocks are of ten repeated, and succeed each other, at short intervals, for a considerable length of time. Awful chasms are sometimes made during the shocks, from which issue water, and in some instances flames. Whole cities have been swallowed up in these chasms, and thousands of people in them. History affords innumerable instances of the dreadful and various effects of earthquakes, |