CHAPTER IV.[1]
PHYSICAL GEOGRAPHY—CLIMATE—GEOLOGY—ZOOLOGY—BOTANY.
Before proceeding to the colonizing era, it will be requisite to present an estimate of the value and importance of the African continent in relation to the rest of the world. This requires some preliminary notice of the physical condition of its territories, and the character and distribution of the tribes possessing them. Africa has not yet yielded to science the results which may be expected from it. Courage and hardihood, rather than knowledge and skill, have, from the circumstances of the case, been the characteristics of its successful explorers. We have, therefore, wonderful incidents and loose descriptions, without the accurate observation and statement of circumstances which can render them useful.
The vast radiator formed by the sun beating vertically on the plains of tropical Africa, heats and expands the air, and thus constitutes a sort of central trough into which gravitation brings compensating currents, by producing a lateral sliding inwards of the great trade-wind streams. Thus, as a general rule, winds which would normally diverge from the shores are drawn in towards them. They have been gathering moisture in their progress, and when pressed upwards, as they expand under the vertical sun, lose their heat in the upper regions, let go their moisture, and spread over the interior terraces and mountains a sheet of heavily depositing cloud. This constitutes the rainy season, which necessarily, from the causes producing it, accompanies the sun in its apparent oscillations across the equator.
The Gulf of Guinea has in its own bosom a system of hurricanes and squalls, of which little is known but their existence and their danger. A description of them, of rather an old date, specifies as a fact that they begin by the appearance of a small mass of clouds in the zenith, which widens and extends till the canopy covers the horizon. Now if this were true of any given spot, it would indicate that the hurricane always began there. The appearance of a patch of cloud in the zenith could be true of only one place out of all those which the hurricane influenced. If it is meant that wherever the phenomenon originated, there a mass of cloud gradually formed in the zenith, this would be a most important particular in regard to the proximate cause of the phenomenon, for it would mark a rapid direction upwards of the atmosphere at that spot as the first observable incident of the series. That the movements produced would subsequently become whirling or circumvolant, is a mechanical necessity. But the force of the movement ought not to be strongest at the place where the mischief had its origin.
The squalls, with high towering clouds, which rise like a wall on the horizon, involve the same principles as to the formation of the vapor, and are easily explicable. They are not necessarily connected with circular hurricanes; but the principles of their formation may modify the intensity of the blasts in a circumvolant tornado. Since in the Gulf of Guinea they come from the eastward, it is to be inferred that they are ripples or undulations in an air current. In regard to all of this, it is necessary to speak doubtfully, for there is a great lack of accurate and detailed observation on these points.
Its position and physical characteristics give to this continent great influence over the rest of the earth. Africa, America, and Australia have nearly similar relations to the great oceans interposed respectively between them. Against the eastern sides of these regions are carried from the ocean those strange, furious whirlings in the shallow film of the earth’s atmosphere, which constitute hurricanes. It is evident that these oceans are mainly the channels in which the surface winds move, which are drawn from colder regions towards the equator. The shores are the banks of these air streams. The return currents above flow over every thing. They are thus prevalent in the interior, so that the climatic conditions there are different from those on the seaboard. These circumstances in the southern extra-tropical regions are accompanied by corresponding differences in the character of the vegetable world.
These winds are sometimes drawn aside across the coast line—constituting the Mediterranean sirocco, and the African harmattan. Vessels far off at sea, sailing to the northward, are covered or stained on the weather side of their rigging (that next to the African coast), with a fine light-yellow powder. A reddish-brown dust sometimes tinges the sails and rigging. An instance of this occurred on board the “Perry” on her outward bound passage, when five hundred miles from the African coast.
The science of Ehrenberg has been searching amid the microscopic organisms contained in these substances, for tokens of their origin. In the red material he finds forms betraying not an African, but an American source, presumed to be in the great plains of the Amazon and Orinoco. This suggests new views of the meteorology of the world; but the theories founded on it, are not clear of mechanical difficulties.
If we stand on almost any shore of the world as it exists at present, and consider the character of the land surface on the one hand, and of the ocean bottom on the other, we shall see that a very great difference in the nature of the beach line would be produced by a depression of the land towards the ocean, or by an elevation of it from the deep. The sea in its action on the bottom fills up hollows and obliterates precipices; but a land surface is worn into ravines and valleys. Hence a depression, so that the waters overflowed the land, would admit them into its recesses, and river courses, and winding gulleys—forming bays, islands, and secure harbors. Whereas elevation would bring up from the bottom its sand-banks and plains, forming an extent of slightly winding and unsheltered shore. The character of a coast will therefore depend very greatly upon its former history, before it became fixed. We have this contrast in the eastern and western sides of the Adriatic, or in the western and eastern sides of the British islands. These circumstances are to some degree controlled by the effects of partial volcanoes, or of powerful winds and currents. But on the whole, it may generally be inferred that a long unbroken shore indicates that the last change on the land level was one of elevation; while a coast penetrated, broken, and defended by islands has received its conformation from being stopped in the process of subsiding.
The coast of Africa has over almost its whole circuit, that unbroken or slightly indented outline which would arise from upheaval. The only conspicuous exception to this, is in the eastern region, neighboring on the Mozambique Channel, where the Portuguese and the Arab possess the advantage, so rare in Africa, of having at their command convenient and sheltered harbors. There are centres of partial volcanic agency in the islands of the Atlantic, north of the equator, and in the distant spots settled by Europeans outside of Madagascar; but this action has not, as in the Mediterranean or Archipelago, modified the character of the continental shore. It is not known that there exists any active volcano on the continent.
Africa, therefore, if it could be seen on a great model of the world, would offer little, comparatively, that was varied in outline or in aspect. There would be great tawny deserts, with scanty specks of dusky green, or threads of sombre verdure tracing out its scant and temporary streams. There would be forests concealing or embracing the mouths of rivers, with brown mountains here and there penetrating through them, but rarely presenting a lofty wall to the sea. Interior plains would show some glittering lakes, begirt by the jungle which they create. But it is a land nearly devoid of winter, either temporary or permanent. Only one or two specks, near the mouth of the Red Sea, and a short beaded line of the chain of Atlas, would throw abroad the silver splendor of perpetual snow. It is the great want of Africa, that so few mountains have on their heads these supplies for summer streams.
The sea-shore is generally low, except as influenced by Atlas, or the Abyssinian ranges, or the mountains of the southern extremity. There is, not uncommonly, a flat swampy plain, bordering on the sea, where the rivers push out their deltas, or form lagoons by their conflict with the fierce surge upon the shore. Generally at varying distances, there occur falls or rapids in the great rivers, showing that they are descending from interior plains of considerable elevation. The central regions seem, in fact, to form two, or perhaps three great elevated plateaux or terraced plains, having waters collected in their depressions, and joined by necks; such as are the prairies of Illinois, between the St. Lawrence and the Mississippi, or the llanos of South America between its great rivers. The southern one of these African plains approaches close to the Atlantic near the Orange River. Starting there at the height of three thousand feet, it proceeds round the sources of the river, and spreads centrally along by the lately visited, but long known lakes north of the tropic. The equinoctial portion of it is probably drained by the Zambeze and the Zaire, flowing in opposite directions. It appears to be continuous as a neck westward of Kilmandjaro, the probable source of the Nile; till it spreads out into the vast space extending from Cape Verde to Suez, including in it the Niger and the Nile, the great desert, and the collections of waters forming Lake Tzad, and such others as there may be towards Fitre.
The mountains inclosing these spaces form a nearly continuous wall along the eastern side of Africa. The snows of Atlas form small streams, trickling down north and south; and, in the latter case, struggling almost in vain with the tropical heats, in short courses, towards the Desert of Sahara.
There are found separate groups of mountains, forming for the continent a broken margin on the west. There may also be an important one situated centrally between Lake Tzad and the Congo; but there appears no probability of a transverse chain, stretching continuously across this region, as has hitherto had a place on maps, under the title of the “Mountains of the Moon.”
No geological changes, except those due to the elevation of the oldest formations, appear to have taken place extensively in this continent. The shores of the Gulf of Guinea, and of the eastern regions, abound with gold, suggesting that their interior is not covered by modern rocks. The two extremities at Egypt and Cape of Good Hope, have been depressed to receive secondary and tertiary deposits. There may be other such instances; but the continent seems, during a time, even geologically long, to have formed a great compact mass of land, bearing the same relations as now to the rest of the world.
The valleys and precipices of South Africa have been shaped by the mighty currents which circulate round the promontory of the Cape; and the flat summit of Table Mountain, at the height of three thousand six hundred feet, is a rocky reef, worn and fretted into strange projections by the surge, which the southeasters brought against it, when it was at the level of the sea.
The present state of organized life in Africa tells the same tale. It indicates a land never connected with polar regions, nor subjected to great variations of temperature. Our continent, America, is a land of extremes of temperature. Corresponding to that condition, it is a land characterized by plants, the leaves of which ripen and fall, so that vegetation has a pause, waiting for the breath of spring. All the plants of southern Africa are evergreens. The large browsing animals, such as the elephant and rhinoceros, which cannot stoop to gather grass, find continuous subsistence in the continuous foliage of shrubs. America abounds with stags or deer—animals having deciduous horns or antlers. Southern Africa has none, but is rich in species of antelopes, which have true or permanent horns, and which nowhere sustain great variations of heat and cold. Its fossil plants correspond apparently in character to those which the country now bears.
Its fossil zoology offers very peculiar and interesting provinces of ancient life. These have been in positions not greatly unconformable to those of similar phenomena even now. Great inland fresh-water seas have abounded with new and strange types of organization, in character and office analogous to the amphibious forms occurring with profusion in similar localities of the present interior. These, and representatives of the secondary formations, rest chiefly on the old Silurian and Devonian series, the upheaving of which seems to have given the continent its place and outline. Coal is found at Natal, near the Mozambique Channel, but not hitherto known to be of value.
Africa still offers, and will long continue to offer, the most promising field of botanical discovery. Much novelty certainly remains to be elicited there, but it is very dilatory in finding its way abroad. Natal is the region most likely to be sedulously explored for some time. Vegetable ivory has been brought thence, and elastic, hard, useful timber abounds. Much lumber of good and varied character is taken to Europe from the western regions of the continent; but so greatly has scientific inquiry been repelled by the deadly climate, that even the species affording it are unknown, or doubtfully guessed at.
The vegetation of the south is brilliant, but not greatly useful. It affords the type of that which covers the mountains, receding towards the northeast, until they reach perpetual snow near the equator. That which is of a more tropical character, stretches round their bases and through their valleys, with its profusion of palms, creepers, and dye-woods. These hereafter will form the commercial wealth of the country, affording oil, india-rubber, dye-stuffs, and other useful productions.
The wild animals of Africa belong to plains and to loose thickets, rather than to timbered forests. There is a gradation in the height of the head, among the larger quadrupeds, which indicates the sort of country and of vegetation suitable to them.
The musket, with its “villanous saltpetre,” in the hands of barbarians is everywhere expelling from the earth its bulkier creatures, so that the elephant is disappearing, and ivory will become scarce. Fear tames the wildest nature; even the lion is timid when he has to face the musket. The dull ox has learned a lesson with regard to him; for when the kingly brute prowls round an unyoked wagon resting at night, and his growl or smell makes the oxen shake and struggle with terror, they are quieted by the discharge of firearms.
When Europeans first visited the shores of Africa, they were astonished at the tameness and abundance of unchecked animal life. The shallow bays and river lagoons were full of gigantic creatures; seals were found in great numbers, but of all animals these seem the most readily extirpated. The multitudes which covered the reefs of South Africa are nearly gone, and they seem to be no longer met with on the northern shores of the continent. The manatee, or sea-cow, and the hippopotamus, frequented the mouths of rivers, and were killed and eaten by the natives. They had never tamed and used the elephant: that this might have been done is inferred from the use of these animals by the Carthaginians. But as the Carthaginian territory was not African in the strict sense of the term, it may be doubted whether their species was that of Central Africa. This latter species is a larger, less intelligent looking, and probably a more stubborn creature than the Asiatic. The roundness of their foreheads and the size of their ears give them a duller and more brutal look; the magnitude of their tusks, and the occurrence of these formidable weapons in the female as well as in the male, are accommodated to the necessity of conflict with the lion, and indicate a wilder nature.
Lions of several species, abundance of panthers, cats, genets, and hyenas of many forms, mainly constitute the carnivorous province, having, as is suitable to the climate, a high proportion of the hyena form, or devourers of the dead. A foot of a pongo, or large ape, “as large as that of a man, and covered with hair an inch long,” astonished one of the earliest navigators. This animal, which indicates a zoological relationship to the Malayan islands, is known to afford the nearest approach to the human form. The monkey structure on the east coast of Africa tends to pass into the nocturnal or Lemurine forms of Madagascar, where the occurrence of an insulated Malayan language confirms the relationship indicated above.
The plains with bushy verdure nourish the ostrich and many species of bustards over the whole continent. Among the creatures which range far are the lammergeyer, or bearded eagle of the Alps, and the brown owl of Europe, extending to the extremity of the south. Among the parrots and the smaller birds, congregating species abound, forming a sort of arboreal villages, or joint-stock lodging-houses. Sometimes hundreds of such dwellings are under one thatch, the entrances being below. The weaving birds suspend their bottle-shaped habitations at the extremities of limber branches, where they wave in the wind. This affords security from monkeys and snakes; but they retain the instinct of forming them so when there is no danger from either the one or the other.
Reptiles abound in Africa. The Pythons (or Boas) are formidable. Of the species of serpents probably between one-fourth and one-fifth are poisonous; but every thing relating to them in the central regions requires to be ascertained. The Natal crocodile is smaller than the Egyptian, but is greatly dreaded.
The following instance of its ferocity occurred to the Rev. J. A. Butler, missionary, in crossing the Umkomazi River, in February, 1853. “When about two-thirds of the way across, his horse suddenly kicked and plunged as if to disengage himself from the rider, and the next moment a crocodile seized Mr. Butler’s thigh with his horrible jaws. The river at this place is about one hundred and fifty yards wide, if measured at right angles to the current; but from the place we entered to the place we go out, the distance is three times as great. The water at high tide, and when the river is not swollen, is from four to eight or ten feet deep. On each side the banks are skirted with high grass and reeds. Mr. Butler, when he felt the sharp teeth of the crocodile, clung to the mane of his horse with a death hold. Instantly he was dragged from the saddle, and both he and the horse were floundering in the water, often dragged entirely under, and rapidly going down the stream. At first the crocodile drew them again to the middle of the river, but at last the horse gained shallow water, and approached the shore. As soon as he was within reach natives ran to his assistance, and beat off the crocodile with spears and clubs. Mr. Butler was pierced with five deep gashes, and had lost much blood.”