291 CHAPTER XVIII. GENERAL FEATURES OF AFRICA.-AFRICAN ISLANDS.-AFRICAN VOLCANIC REGION. O'er Africa the morning broke; From Europe's eye and Europe's yoke, MONTGOMERY. THE vast peninsula of Africa presents some very striking natural features. A large portion of this division of the globe is situated within the tropics; and its extreme northern and southern limits are nearly at an equal distance from the equator. If, therefore, general uniformity of climate depended solely upon latitude, we might expect to meet with great similarity in this respect in all parts of Africa. It, however, appears, that the other conditions producing diversity of climate-such as the alternations of highland and lowland, the absence or presence of rivers, the inequality of the mass of land, and consequent remoteness from, or proximity to, the ocean-are exhibited on a large scale in these extensive regions, causing great variety of temperature and fertility. The whole northern portion of Africa, with the exception of the eastern extremity, is occupied by the extensive range of the Atlas Mountains, and their various branches. These mountains, which in some parts rise above the snow-line, give origin to several rivers and streams, which find an outlet either in the Mediterranean Sea, or the Atlantic Ocean; and although, from the proximity of these mountains to the shores, these streams do not form important rivers, they fertilize the rich plains of Barbary and Marocco. Another great mountain system of Northern Africa, consists of the lofty ranges of Samen and Taranta, which are prolonged in the Donga Mountains, or Mountains of the Moon, which extend far into the interior, forming a succession of elevated terraces and table-lands, throughout Abyssinia and the adjacent country. The mountains of Abyssinia, or Geesh, estimated at fifteen thousand feet above the sea, appear to form the most elevated portion of this range. The central part of Africa is very little known; but the greater portion of that region is supposed to be occupied either by mountains or by elevated plateaus; an inference drawn from the occurrence of numerous important rivers, which are either known, or considered, to take their rise in those regions. Among these, we may mention the Nile, which takes a northerly course; and the Senegal, the Quorra, and various other rivers, which empty themselves into the Atlantic Ocean. The eastern portion of Africa is scarcely better known than the interior, but a range of mountains, more or less continuous, is supposed to extend from Abyssinia to the southern extremity of Africa. The latter region is occupied by mountains of inferior elevation to those of Northern Africa, but which, nevertheless, do not fail to produce very important modifications in the climate and temperature of the country. The most elevated are, perhaps, the Nieuveldt Mountains, which, in some parts, are considered to reach the height of ten thousand feet above the sea, and present some snow-capped summits. The Kous Mountains, which separate Caffraria from the Bechuana country, do not appear to exceed six thousand feet in height; and the Cedar Mountains, with their prolongation, the Kamies or Lion Mountains, range from one thousand six hundred to five thousand feet above the sea level. The Cedar Mountains are described by Sir James Alexander as being very beautiful, with a highly picturesque outline, and adorned with great numbers of the cedar of Lebanon, which tree here attains a magnificent size, and with which these mountains were formerly covered. Marine fossils are found in this range, at the elevation of two thousand feet above the sea; and fine jasper, agates, and garnets, are of frequent occurrence. The extreme south is occupied by the conspicuous, though not very elevated mountain group, which rises immediately above Cape Town, and which includes the precipitous table-mountain, 3580 feet above the sea, and its two supporters, called the Devil's Head, and the Lion's Head. ^ In Western Africa we meet with the Qua Mountains, and the Rumli range; the former being about five thousand, and the latter three thousand feet, in general elevation. The most lofty mountain in this portion of Africa is the Peak of Cameroon, which attains the height of thirteen thousand feet above the sea, and is covered nearly to the summit with trees of luxuriant growth. This elevated mountain is situated at no great distance from Fernando Po, in which island, the lofty summit of Clarence Peak reaches the height of ten thousand feet. Between Fernando Po and the mainland, there is a depth of forty fathoms; and this locality appears to present one of the most remarkable undulations on the surface of the globe. The Kong Mountains, which commence at Cape Verde, and form the southern boundary of the Sahara, or Sahrà, extend to an unknown distance in the interior. The most striking feature, however, in the natural geography of Africa, is the great extent of desert occupying various portions of this region, and which, for the most part, is without elevated land, and destitute of streams of water. The deserts of Northern and Southern Africa, however, although they may agree in their general character, differ very considerably in their particular features. The Sahrà, or Great Desert, as before observed, with the exception of an occasional wady, or oasis, consists chiefly of low rocky hills, and boundless extents of moving sands, parched and pulverized by the intense heat of a tropical sun. "There," says Captain Belcher, "the very atmosphere is sand; the grains of drift sand varying in size, from an almost impalpable powder to that of hemp-seed." "I found," continues the same officer, speaking of the country round Cape Blanco, "the grains equal to dust shot, almost insupport able; but what must a gale of hemp-seed size prove?" Such, however, is the nature of this vast desert, which covers an area nearly three times as great as that of France, and which extends from the shores of the Atlantic to the borders of Egypt. In such a country, where there is No shade, all sun, insufferably bright, we shall not expect that animal life will appear in the same exuberance as in well-watered lands, situated in parallel latitudes; and, in fact, we find that, with the exception of an occasional troop of gazelles (fig. 90), or of ostriches (fig. 128), occurring on its outskirts, or perhaps a few jerboas (fig. 50), and similar animals, in the vicinity of the wadys; to which may be added a small number of beetles, and other insects adapted to endure the scorching heat of these arid sands, the Sahrà may be said to be entirely destitute of inhabitants. As we approach the borders of Egypt, the wadys become more frequent and of greater extent; and at length, on the borders of the Nile, the desert tract is changed into one of the greatest fertility. The occurrence of these wadys, or oases, wherever springs exist, leads to the conclusion, that the sterility of the Sahrà arises from no peculiarity of soil, but from the absence of water; there being no rivers to irrigate and fertilize the western portion of this belt, and rain being almost unknown in its whole extent. This deficiency of water arises in great measure from the configuration of its surface, and its want of trees. We havė seen that mountains and trees attract and condense moisture, and, as this region, in its interior, is destitute of both those requisites, the few clouds which may be wafted across it from the Atlantic, become rapidly dispersed by the intense heat, and do not descend in refreshing showers. Between the Sahrà and the Atlas Mountains, extensive districts are covered by the date-palm (fig. 175), an abundant supply of food being thus bountifully provided, for the inhabitants of the territory bordering on that desolate waste. The deserts or karroos of Southern Africa, differ widely from the Sahra, approaching rather in character to the steppes of Northern Asia. This difference is attributable, partly to the undulations of the surface in Southern Africa, and partly to the greater proximity of every portion of this region, to the waters of the ocean; in consequence of which, these districts receive abundant supplies of rain. These rains are, however, periodical, and the karroos experience a dry season, at which time all vegetation disappears. Like the Sahrà, they possess a sandy soil, but this, instead of presenting a moving surface, is firmly bound together by the fibres and roots of various plants, which at all times derive a certain supply of nourishment from the soil; but which, in the rainy season, spring up, and cover the whole country with rich and spontaneous verdure. These karroos are not, therefore, like the arid Sahrà, unsuited for the support of animal life; but, on the contrary, are peculiarly adapted for the temporary sustenance of such graminivorous animals, as possess sufficient speed of foot, to enable them to traverse a considerable extent of country in search of congenial food. And, accordingly, we find that the Creator has adapted the animal to the vegetable productions of this region; for no country abounds so much as does Southern Africa, with vast herds of gazelles, spring-boks, and other species of antelopes. A large portion of Central Africa, being wholly unknown to Europeans, we cannot attempt to trace even an outline of the interior districts; though under this head we may, perhaps, not inappropriately, consider the fertile regions situated to the south of the Sahrà, to which latter, this portion of Africa presents a strong contrast. This difference is, however, readily accounted for by the different nature of the surface; the regions we are now considering being traversed by lofty mountain ranges, which give rise to numerous magnificent rivers, and diffuse both coolness and moisture over the whole district; thus rendering it one of the finest countries on the face of the globe. These mountains approach the Atlantic near Sierra Leone, which place has |