ocean, though encircling the globe on every side, and stretching from pole to pole, is also arranged in areas more or less defined by the intervention of the land-masses. The main divisions are the Atlantic, the Pacific, Indian, Arctic, and Antarctic Oceans, which, for convenience of description, are frequently subdivided into North and South Atlantic, North and South Pacific, Northern, Southern, and Polar Seas. The technicalities employed in treating of the relations of land and water-shore-line, coast-line, island, peninsula, isthmus, cape, bay, gulf, strait, channel, and the like— are so obvious, and of such frequent use in everyday language, as scarcely to require any special explanation. The physical results arising from the present distribution of sea and land are manifested chiefly in tides, currents, unequal reception and radiation of the sun's heat; and as a consequence, winds, vapours, rains, and all the other phenomena that give rise to climatic diversity. What may be the proximate cause of the present arrangement of sea and land -why the land should lie chiefly in the northern hemisphere, and largely within the temperate zone, while it disappears in a succession of narrow cape-like lobes towards the south-neither Geology nor Geography can determine. One thing, however, is certain, that it is part of a great geological sequence of continuous oscillations between sea and land, each change being attended by its own physical and vital phenomena; and that, as in the past history of the globe, so in the present, no alteration in this terraqueous arrangement can take place without a corresponding alteration in all the essentials of Physical Geography.

For the minor subdivisions of land and water, which are arbitrary and political, rather than physical, the student may consult Mackay's Manual of Modern Geography, or any similar work equally recent and ample in its information.

V.

THE LAND-ITS CONFIGURATION.

45. HAVING glanced at the distribution of land and water, and their general relations to each other, as composing the terraqueous surface of the globe, we now proceed to consider their special features-the mountains, table-lands, plains, and valleys of the one— the composition, depth, temperature, tides, and currents of the other. And first, in the present chapter, of the Land, whose features are more within our reach, and have been longer and more minutely the subjects of geographical investigation. How is this dry land disposed on the surface of the globe? This is its position as depending on latitude and longitude. What the outline of its form or shape as regards the ocean, by which it is on every side surrounded? This, in geographical language, is its contour. How, again, does it rise above the waters; and what the surface inequalities presented to the atmosphere? This is its vertical relief. Position is the place it occupies on the surface of the globe; contour the outline bathed by the waters of the ocean; vertical relief the surface-line that rises into the atmosphere; and the student will readily perceive that upon these three elements of position, contour, and relief, depend the climate, physical aspects, and vital diversity of any portion of the dry land.

Relative Position.

46. Latitude and longitude, we have said, determine the position of any spot on the earth's surface, be it islet, island, or continent; and just as these limits bring it within tropical, temperate, or arctic zones, so will its climate and products assume aspects of a corresponding character. How different the physical and vital characteristics of Europe and Asia had they lain mainly within tropical, instead of stretching, as they now do, mainly along tem

perate latitudes! How different also the condition of North and South America if, instead of stretching from north to south, through all the different zones of temperature, they had lain, like the Old World, from east to west, along the same parallels of latitude! And how altered, in like manner, had been the physical, vital, and perhaps also the intellectual, characteristics of Great Britain, if, instead of trending northward and southward, between the 50th and 60th parallels, it had stretched westward to the same extent into the waters of the Atlantic! Position, in fact, is an all-important element in geography; hence the value of accurate mapping, and a knowledge of this mapping to every one, whether engaged in commercial pursuits or in the study of natural phenomena. The cause of the present position of the dry land lies far, as yet, beyond the indications of science. We learn from Geology that the existing position is not that which obtained in former ages; and that, in fact, every epoch was characterised by its own special distribution of land and water. The consideration of these alternations belongs to Geology: Geography has mainly to deal with the existing aspects of nature.

Contour or Horizontal Outline.

47. Though Geology and Geography are alike unable to account for the present disposition of sea and land, there are still some features in the contour of the respective land-masses that demand a passing notice. Not that we know the producing cause of these features, nor that they are deserving the attention occasionally bestowed upon them, but simply because they are arrangements productive of obvious results, and as such are clearly significant of purpose and design. Thus, though the greater bulk of the land lies in the northern hemisphere, the greatest extension of the Old World continent is from east to west, while that of the New World is from north to south. In this way, the Old World, lying largely along the same zones, presents a greater uniformity of external conditions; while the New World, crossing the zones-frigid, temperate, and torrid-is subject to a greater diversity of temperature, and, as a consequence, to all the conditions that arise from this diversity. 2. Both continents attain their greatest dimensions from east to west along the same parallel of latitude, namely, that of 50° N.-a disposition that places much of North America, Europe, and Asia within the temperate zone, while only the narrower portions of South America, Africa, and the East India Islands lie directly under the burning heat of the equator. 3. Both continents,

as formerly noticed, spread widely towards the north, where they nearly approach each other, and terminate broadly along the same parallel (72° N.) or nearly so; while, towards the south, they gradually grow narrower, and terminate in far-separated promontories. Indeed, the southward trending of the great lobes of South America, Africa, and Australia, and their separation from their main continents by narrow isthmuses or islands, has suggested the analogy of three double worlds-North and South America, EuropeAfrica, and Asia-Australia—a curious coincidence certainly, which a glance at the map will readily confirm. 4. In like manner, the direction of all the principal spurs and peninsulas in both continents (California, Florida, Greenland, Scandinavia, Spain, Italy, Greece, Hindostan, Malaya, Kamtchatka, &c.) is towards the south-a feature by far too general not to suggest to the inquiring mind a sameness in the producing cause. 5. These southward-trending spurs, moreover, are in most instances curiously accompanied by an outlying island or islands as South America by Tierra del Fuego and the Falkland Islands, Africa by Madagascar, Hindostan by Ceylon, and Australia by Tasmania. And in connection with this may be noticed the fact, that these promontories terminate in abrupt rocky precipices-as Cape Horn, in Tierra del Fuego; Cape of Good Hope, with its Table Mountain; Cape Comorin, in India; and Cape South-East, in Tasmania-all the broken and worn extremities of expiring mountain-chains.

48. Continuing these analogies, we may notice, 6. The general disposition of the continents and larger islands in the direction of their principal mountain-axes; so that, given the direction of the mountain-chains, we know the longitudinal disposition of a continent, or given the direction of a continent, and we can foretell the strike of its mountains. 7. The almost complete separation of South America from North America, of Africa from the Old World, and the severance of Australia from Asia; as well as the curious resem. blance that obtains between North America with the West India Islands on its south-east, Europe with the Grecian islands on the south-east, and Asia with the Indian Archipelago in the same quarter, are curious coincidences that have been long noticed by geographers. 8. The general tendency of islands to arrange themselves in clusters or archipelagoes, is a fact also suggestive of a common geological cause. And, lastly, the numerous indentations of the that confer irregularity and extent of coast-line on the land in the northern hemisphere, is a feature that strongly contrasts with the uniform and unbroken coasts of South America, Africa, and Australia, in the southern hemisphere. Indeed, this last relation -viz., that of a broken and deeply indented coast-line, furnished

sea,

with peninsulas, gulfs, inland seas, and harbours-is one of the most important in Physical Geography, as on it depend greater diversity of climate and productions, and all those facilities for navigation and commerce which confer on nations their wealth, power, and independence. Europe and North America stand pre-eminent for their relative extent of coast-line; and hence in a great measure their industry, maritime enterprise, and civilisation. Assuming that the capacity of a country for external communication can in some degree be estimated by the proportion of its coast-line to its superficial area, the following tabulation will briefly exhibit this relation :

Here it will be seen that Europe has 1 mile of coast for every 170 square miles of surface, and North America 1 mile of coast for every 260 square miles of surface—a proportion more than double that of the other continents; hence one great physical reason for the commercial and industrial supremacy of their populations.

49. Besides the preceding analogies, there are several others that have been noticed by geographers; and though such comparisons are often more fanciful than real, they are all less or more suggestive, and may occasionally lead to a satisfactory theory. But whatever may have been the causes that produced the present arrangement of the land-masses, no change could take place in their relative situations without being attended by corresponding changes in the nature of their climate, and in the character of their vegetable and animal inhabitants. Had they lain chiefly within the tropics-been situated partly in the northern and partly in the southern hemisphere, with a broad belt of tropical ocean between-been arranged either longitudinally or latitudinally in parallel zones, or been broken up into smaller masses by the more frequent intervention of the ocean-a totally different set of climatic agents would have prevailed, and been consequently attended by a totally different distribution of plants and animals. During geologic changes, when large tracts are being gradually submerged and others are gradually elevated into dry land, whole races of plants and animals are extinguished, while others shift ground and find means of dispersion over the newly elevated regions. present the plants and animals of the Old World differ from those

At