But we have not placed the title of Mrs Somerville's book at the head of this paper, as an occasion to involve ourselves in these dark and abstract discussions. We are for out-of-door life; we would survey this visible round world, whose various regions, with their products and their inhabitants, she has brought before us.
"Physical geography," thus commences our writer, "is a description of the earth, the sea, and the air, with their inhabitants animal and vegetable, of the distribution of these organised beings, and the causes of that distribution. Political and arbitrary divisions are disregarded: the sea and the land are considered only with respect to these great features, that have been stamped upon them by the hand of the Almighty; and man himself is viewed but as a fellow-inhabitant of the globe with other created things, yet influencing them to a certain extent by his actions, and influenced in return."
Physical geography stands thus in contrast with political and historical geography. Russia is here no despotism, and America no democracy; they are only portions of the globe inhabited by certain races. To some persons it will doubtless seem a strange "geography" that takes no notice of the city, and respects not at all the boundaries of states. Those to whom the name recalls only the early labours of the school-room, when counties and county-towns formed a great branch of learning—where the blue and red lines upon the map were so anxiously traced, and where, doubtless, some suspicion arose that the earth itself was marked out by corresponding lines, or something equivalent to them—will hardly admit that to be geography which takes no note of these essential demarcations, or allow that to be a map in which the very city they live in cannot be found. To them the Physical Atlas will still seem nothing but a series of maps, in which most of the names have still to be inserted. They unconsciously regard cities and provinces as the primary objects and natural divisions of the earth. They share something of the feeling of that good man, more pious than reflective, who noted it as all especial providence that all the great rivers ran by the great towns.
Others, however, will be glad to escape for a time from these landmarks which man has put upon the earth, and to regard it in its great natural lineaments of continent and sea, mountain and island. To do this with advantage, it is necessary to disembarrass ourselves, both in the book and the map, of much that in our usual nomenclature ranks pre-eminently as geography. Nor is it easy to study this, more than the older branch of geography, without an appropriate atlas. To turn over the maps of Mr Johnston's, and con the varied information which accompanies them, is itself a study, and no disagreeable one. Of the extent of this information we can give no idea by extract or quotation; it is manifestly in too condensed a form for quotation; it is a perfect storehouse of knowledge, gathered from the best authorities.
The first thing which strikes an observant person, on looking over a map, or turning round a globe, is the unequal division and distribution of land and water. Over little more than one-fourth of the surface of the earth does dry land appear; the remaining three-fourths are overflowed by water. And this land is by no means equally disposed over the globe. Far the greater part of it lies in the northern hemisphere. "In the northern hemisphere it is three times greater than the south."
Of the form which this land assumes, the following peculiarities have been noticed:—
"The tendency of the land to assume a peninsular form is very remarkable, and it is still more so that almost all the peninsulas tend to the south—circumstances that depend on some unknown cause which seems to have acted very extensively. The continents of South America, Africa, and Greenland, are peninsulas on a gigantic scale, all tending to the south; the Asiatic peninsula of India, the Indo-Chinese peninsula, those of Corea, Kamtchatka, of Florida, California, and Aliaska, in North America, as well as the European peninsulas of Norway and Sweden, Spain and Portugal, Italy and Greece, take the same direction. All the latter have a rounded form except Italy, whereas most of the others terminate sharply, especially the continents of South America and Africa, India, and Greenland, which have the pointed form of wedges; while some are long and narrow, as California, Aliaska, and Malacca. Many of the peninsulas have an island, or group of islands, at their extremity—as South America, which terminates with the group of Terra del Fuego; India has Ceylon; Malacca has Sumatra and Banca; the southern extremity of New Holland ends in Van Diemen's Land; a chain of islands run from the end of the peninsula of Aliaska; Greenland has a group of islands at its extremity; and Sicily lies close to the termination of Italy. It has been observed, as another peculiarity in the structure of peninsulas, that they generally terminate boldly, in bluffs, promontories, or mountains, which are often the last portions of the continental chains. South America terminates in Cape Horn, a high promontory which is the visible termination of the Andes; Africa with the Cape of Good Hope; India with Cape Comorin, the last of the Ghauts; New Holland ends with South-East Cape in Van Diemen's Land; and Greenland's farthest point is the elevated bluff of Cape Farewell."
These are peculiarities interesting to notice, and which may hereafter explain, or be explained by, other phenomena. Resemblances and analogies of this kind, whilst they are permitted only to direct and stimulate inquiry, have their legitimate place in science. It was a resemblance of this description, between the zig-zag course of the metalliferous veins, and the path of the lightning, which first suggested the theory, based, of course, on very different reasonings, that electricity had essentially contributed to the formation of those veins—a theory which Mrs Somerville has considered sufficiently sound to introduce into her work.
What lies within our globe is still matter of conjecture. The radius of the earth is 4000 miles, and by one means or another, mining, and the examination of the upheaved strata, and of what volcanoes have thrown out, we are supposed to have penetrated, with speculative vision, to about the depth of ten miles.