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its solution be affected by, the distance
pleting it. Thus, by the aid of the true length of a degree, was finally established the grand theory of Universal Gravitation.
THE subjects embraced in the foregoing treatise, are dispersed throughout a great number of different books, and are to be met with only in detached parts.
The proofs of the spherical figure of the earth, and the methods of finding the latitudes and longitudes of places, will be found in every Treatise of Astronomy; we shall, therefore, only refer to that part of Malte-Brun's work, which is devoted to Mathematical Geography; to the Nautical Almanack; Woodhouse's Astronomy, vol. i.. chapters 1, 5, 42 and 43; Brinkley s Elements of Astronomy, chapters 1, 3, 16 and 17; Playfair's Outlines of Natural Philosophy, vol. ii. part 1, chapters 1 and 4; and, as a popular work, to Bonnycastle's Astronomy, letters 2, 9 and 10.
For fuller information, with respect to the true figure of the earth, and the lengths of pendulums vibrating seconds in different latitudes, and measurement and lengths of degrees, we may refer to Malte-Brun; Brinkley, chap. 17; Playfair, chap. 3, of part 1, and chap, 6, of part 2; Bonnycastle, letters 15 and 16; Newton's Principia, book 3, props. 18, 19 and 20; Maclaurin's Account of Sir I. Newton's Discoveries, book 4, chap. 6; Pemberton's View of Sir I. Newton's Philosophy, book 2, chap. 6; Rees' Cyclopædia, articles, Earth," and Degree; various Papers in the Philosophical Transactions on the Measurement of Degrees, and on Experiments upon the Pendulum; Clairaut Figure de la Terre; Quarterly Journal of Science, for March 1827, p. 177.
PHYSICAL or natural geography might, if we regarded merely the strict meaning of the words, be limited to signify no more than a description of the principal features of the earth's surface; but it is usual, in treatises upon this branch of geography, to touch also upon the subject of climate and temperature, to show how these, together with other natural causes, affect the condition of the human race-and to advert, in a general manner, to the animals and productions of the globe.
Geographical terms explained. In looking over a map of the world, it is seen at once that the surface consists of various spaces of land, surrounded by an extensive field of water called the sea or ocean. Of these spaces of land, two are of vast extent, and on this account are termed continents
(derived from a Latin word signifying, holding together or connexion). The larger of these continents includes the three divisions of Europe, Asia, and Africa, and is distinguished by the title of the old continent, from its having, till the discovery of America, by Columbus in the year 1492, been the only one with the existence of which Europeans were acquainted. The other, which includes North and South America, is named the new continent. The smaller portions of land which are scattered over the ocean are denominated islands. A
• New Holland, by some geographers, is regarded
as a third continent; but if we consider how much smaller it is than either of the two vast tracts abovementioned, it will appear correct rather to assign it the first station among the islands of the globe. New Holland and the islands around it are, however, not unworthy of being classed as the fifth grand division of the world. English geographers have named them Australia (that is, Southern lands.)
great many islands lying together are called an archipelago.
In many places the land and the ocean run one into the other. When the ocean penetrates into a continent by a narrow passage, and then spreads again into a large expanse, this inland portion of the ocean is usually termed a sea. If the extent of such an inland sea be less, or the passage by which it communicates with the main ocean larger, it is called a gulf or bay. An inland body of water not connected with the ocean or any of its branches, is called a lake. A narrow passage of water leading from one sea to another is called a strait; a narrow neck of land lying between two seas, and connecting two masses of land greater than itself, is called an isthmus. When, on the out into the sea, and is joined to the other hand, a part of a continent runs main land by only a small portion of its circumference, it is named a peninsula, (that is, an almost island). If the projections of land reach but a little way into the sea, they are called headlands, or promontories.
General View of the Globe as consist
ing of Land and Sea.
There is, in fact, only one continuous fluid surrounding the land, all the gulfs and inland seas being branches of this universal ocean; but for the sake of convenience different parts of it have distinct names given to them. The following table, exhibiting the principal seas into which the ocean has been divided, will be clearly understood upon referring to the map of the world on Mercator's projection:
The Caspian Sea, as it is generally termed, forms no exception to this remark, because it is in fact only an immense lake.
The great South East
ern basin, the waters of
ly half the
globe. It includes
The Western basin, forming
channel between the old and new continents.
1. The Antarctic Ocean, which is comprised within the Antarctic circle, that is, between the parallel of 66° 32′ of southern latitude and the South Pole.
2. The Southern Ocean, the boundary of which on one side is the Antarctic circle, on the other a line drawn from Cape Horn to the Cape of Good Hope, thence to Van Diemen's Land, and again by the south of New Zealand to Cape Horn. This line forms the southern boundary of Nos. 3 and 4.
3. The Indian Ocean, lying between Africa on the west, and the peninsula of Malaya with the islands of Sumatra, Java, &c., and New Holland, on the east, and bounded by Persia, and Hindustan on the north. The Red Sea, or Arabian Gulf, the Persian Gulf, and the Bay of Bengal are all parts of this ocean.
4. The Pacific Ocean, divided by the equator into North and South, and inclosed between America on the east, and New Holland, the islands of Java and Sumatra, and the continent of Asia, on the west. On the north it terminates at Behring's strait. The seas of China, Japan, Okhotsk, &c. torm parts of this ocean.
1. The Atlantic Ocean, commencing in the south from a line drawn from Cape Horn to the Cape of Good Hope, and terminated on the north by the Arctic circle. It is divided into North and South by the equator, and its branches are the Mediterranean, the North Sea or German Ocean, the Baltic, Baffin's Bay, Hudson's Bay, the Gulf of Mexico and the Caribbean Sea.
2. The Arctic Ocean, surrounding the North Pole, and bounded by the Arctic circle and the northern shores of the two continents. The White Sea, the sea of Kara, and the Gulf of Obe are parts of it. The Ocean is spread over nearly seven-tenths of the globe; but it is remarkable how unequally the land and water are distributed. If we look at a map of the world projected upon the horizon of London, in which map, consequently, London forms the centre of the one hemisphere and the antipodes* to London, the centre of the other; the first hemisphere, it will be seen, contains a very large proportion of the whole of Considering the whole space included in the northern part of the torrid zone, as equal to 1, the proportion of land is
the land, while the second, if we except New Holland and the extremity of South America, from the twenty-ninth degree of south latitude, consists almost entirely of water. The distribution of water and land is still very unequal, if we compare only the northern and southern hemispheres, that is, the two equal parts into which the globe is divided by the equator. The following calculation will plainly exhibit this fact:
On the same supposition, the proportion of land in the northern temperate zone is
And in the northern icy zone
In the southern part of the torrid zone, the portion of land is
In the southern icy zone (supposed)
In other words, if the quantity of land in the northern hemisphere be represented by 16, the quantity in the southern will be scarcely equal to 5.
About the middle of the last century it was sserted that a great continent must exist towards the south pole, in order to counterbalance the mass of land in the northern hemisphere; but by the voyages of Cook and others, it has been proved that the high southern latitudes contain only a few islands.The absence of a continent near the
south pole does not of itself prove that there is less land there than in the north, since it is possible that the land in general may be only rather more depressed in the south, the necessary result of which would be, that the ocean would spread itself more extensively over the surface of the earth in that quarter.
A small island lying to the south-east of New Zealand, and called Antipodes island, is very nearly the antipodes to London,
On the Figure, &c., of the Continents. The general direction of the land in the two continents is entirely different. In America, it is from pole to pole; in
the old world, it is from south-west to north-east, and, if we keep Africa out of view, it is almost parallel to the equator. The longest straight line that can be drawn on the old continent commences on the western coast of Africa, from
about Cape Verd, and extends to Behring's strait in the north-east of Asia. It is about 11,000 miles in length. A similar line, traced along the new continent, passes from the strait of Terra del Fuego, to the northern shore of North America, and is nearly 9000 miles long. In both continents the direction of the large peninsulas is similar, almost all of them running towards the south. This is the case with South America, California, Florida, Alaska, and Greenland in the New World, and in the Old with Scandinavia, Spain, Italy, Greece, Africa, Arabia, Hindustan, Malaya, Cambodia, Corea, and Kamtchatka. The only exceptions to this remark, are the peninsula of Yucatan in Mexico, and that of Jutland in the north-west of Europe. Both of these are directed towards the north; but they consist of plains and alluvial land, whereas the other peninsulas are more or less of a mountainous character. There is a further resemblance be
tween the two continents, from each being divided into two parts by an isthmus *; but in the character of their outlines they differ very much for while the coast of the Old World (independent of Africa) is broken equally on all sides by gulfs, bays, and inland seas, the New World has a series of openings on its eastern shore only. Of its western side, the only inlet of any magnitude is the gulf of California.
Mountains are the most considerable elevations of the surface of the earth. They may be divided into two classes: those of which the chains are the most lofty, rugged, and extensive, such as the Andes, the mountains of central Asia, the Alps, &c., and those of a less majestic character, which frequently
form branches as it were of the first class. The Apennines, which traverse the whole length of Italy, and the Car
The isthmus of Suez is composed of sand; that of Panama or Darien consists of stupendous rocks.
pathian range, which in a great meacond description. All elevations which sure surrounds Hungary, are of this setake place in such a gradual manner as are either of such an inferior kind, or not to come within these two classes, are termed hills or slopes.
Mountains most commonly are so near to each other, and are disposed in such a manner, as to give the idea of chains. A chain may be defined as a series of mountains, the bases of which that the name is sometimes applied to are continuous; but it is well to observe collections of hills without much regard to its strict meaning. Sometimes chains which proceed from the high table-land run out from a common centre: those of central Asia, may be considered as an example; at others the centre mass itchains are attached: such are the Alps. self is a lofty chain to which secondary In some instances there are irregular groups of several chains, among which this the mountains in Asia Minor and none can be ranked as the principal: of Persia are examples. The most remarkable, however, are long connected chains, which, like the Andes, conin one direction, having on both sides tinue for several thousand miles, nearly inferior ranges, but sending off hardly any secondary chains. These appear to be of the highest antiquity.
Some mountains are completely insulated, that is, are quite remote from any chain or group. Volcanoes are more particularly of this kind.
The character of mountains would of which they are composed. Granite, seem to depend upon the sort of rock when exposed, forms lofty and rugged elevations; gneiss is much less precipitous, and slate commonly not at all
able difference, which Humboldt has In this respect there is a remarknoticed, between the Old and New Continents. In the former the highest points of the Alps consist of granite; but in America, granite is not found higher than 11,000 or 12,000 feet above the level of the sea, and the newest floetz trap or whinstone, which in Europe appears only in low mountains, or at the foot of those of great magnitude, covers the tops of the Andes. Chimborazo and Antisana are crowned with vast walls of porphyry; and basalt, which in our
The name of Andes is given only to the chain on the west coast of South America; the continuation of that chain in North America has other titles; but they evidently form one grand whole.
continent has not been observed higher than 4300 feet, is on the very summit of Pichincha. Other secondary formations, among which may be mentioned limestone, are also found at greater heights in the New than in the Old world.
With respect to their declivities, it is observed that most of the principal mountains have one of their sides very steep, and the other of a gradual slope. The Alps, for instance, have a much more abrupt descent on the side of Italy than on that of Switzerland; the Pyrenees are steeper towards the south than the north, while the chain of Asturias, which branches westward from the Pyrenees, is just the reverse. Mount Taurus, in the part where it approaches the Mediterranean and the Dardanelles, is abrupt on the south, but in Armenia it has a rapid descent northward. The mountains of Scandinavia are steeper towards the west and north-west, than the south and east; and the Ghauts in Hindustan are in like manner precipitous on the west, and sloping in the opposite direction. With all these chains, therefore, and indeed with most of the chains of the globe, their steepest side is found to be that which approaches most nearly to the sea, and consequently their inclination is most gradual towards the interior of the country in which they are situated.
Mountains in their course commonly make numerous curves and angles; but in most cases the general direction of the principal chains appears almost, if not entirely, to correspond with the greatest length of the continents to which they belong. The Andes in South and the Stony Mountains in North America exemplify this remark; as do also the chains which, with little interruption, pass from the north-eastern point of Asia to the south-west coast of Portugal, and to the western side of Africa. The secondary chains, in the same manner, frequently follow the greatest length of the large peninsulas. This is the case with the Apennines in Italy, the Dovrefield in Scandinavia, the Ghauts in Hindustan, &c.
In order to obtain a connected view of the loftiest and most extensive system of mountains upon the globe, we must suppose ourselves placed in New Holland with our face turned towards the north; America will then be on the right, Asia and Africa on the left. From Cape Horn to Behring's strait
along the western coast of America, there is an almost uninterrupted range of the highest mountains: from Behring's strait again succeeds an enormous line passing in a south-westerly direction through Asia, leaving China and Hindustan to the south, somewhat interrupted as it approaches Africa, but still to be looked upon as continuing its course in the mountains of Persia and Arabia Felix. From Cape Gardafui in Africa to the Cape of Good Hope, there appears to be a chain which completes the view.
The series of mountains which we have thus followed, is in the form of an immense irregular curve, which comprises within it, the Pacific and Indian Oceans, with their innumerable islands, besides a portion of Asia, including China, the Birman dominions, and the Indian peninsula. It presents a steep face towards these oceans, while, on the other side, the land very generally slopes towards the Atlantic and Arctic Oceans.
The following is a table of the height of some of the principal mountains of the globe, reckoning from the level of the sea. The elevations of those in Asia and Africa are far from having been ascertained with accuracy. Some recent measurements make the highest summits of the Himalayan range as much as 28,000 feet; but, though these calculations seem very doubtful, it is not unlikely they are at least 25,000 feet high.