Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/280

there is a considerable elevation, even in its midst there is a periodical rainfall. The Kalahari region is almost rainless, on account of the great heat to which it is subjected; but specially because the winds coming towards it from the eastward, the prevailing winds, expend their moisture on the high slopes of the plateau which face the Indian Ocean. Heavy dews, consequent on the rapid changes of day and night temperature in these bare regions, partly compensate the deficiency of rain.

The portions of the continent which lie beyond the tropics north and south, the outer slopes of the plateau of Barbary and of the Cape Colony, have no marked rainy season, and the times of the occurrence of rain are altered, the summers of both being drier, the showers more frequent in winter. In Natal, and on the slopes of the plateau in its neighbourhood, rain may be expected in any month; but the greatest falls occur from October to March. The absolute quantity of rain which falls in Africa has as yet been measured at so few points, that no definite conclusions can be arrived at respecting it.

Although Africa belongs almost entirely to the torrid and warm zones, its vegetable productions are essentially groves of oranges and olives, plains covered with wheat and barely, thick woods of evergreen oaks, cork-trees, and sea-pines, intermixed with cypresses, myrtles, arbutus, and fragrant tree-heaths, form the principal features of the landscape. On this northern coast the date-palm is first found; but its fruit does not arrive at perfection, and it is chiefly valued as an ornamental object in gardens. Various kinds of grain are cultivated. Beyond this region of the coast and the Atlas chain, with the borers of the Sahara, commences a new scene. It is in this region, extending to the border of Soudan, that the date-tree forms the characteristic feature. Being peculiarly adapted to excessive dryness and high temperature, it flourishes where few other plants can maintain an existence. Were it not for the fruit of the invaluable date-tree, the inhabitants of the desert would almost entirely depend on the products of other regions for their subsistence. With the southern boundary of the Sahara, the date-tree disappears, the baobab or monkey bread-tree takes its place, and, under the influence of the tropical rains, a new, rich, and highly-developed flora presents itself. These trees, together with huge cotton-trees, oil-palms, sago-palms, and others of the same majestic tribe, determine the aspect of the landscape. The laburnum expands its branches of golden flower, and replaces the senna of the northern regions, and the swamps are often covered with immense quantities of the papyrus plant. Instead of waving fields of corn, the cassava, yam, pigeon-pea, and the ground-nut, form the farinaceous plants. The papaw, the tamarind, the Senegal custard-apple, and others, replace the vine and the fig. In Southern Africa, again, the tropical forms disappear, and in the inland desert-like plains, the fleshy, leafless, contorted, singular tribes of kapsias, of mesembryanthemums, euphorbias, crassulas, aloes, and other succulent plants, make their appearance. Endless species of heaths are there found in great beauty, and the hills and rocks are scattered over with a remarkable tribe of plants called Cycadaceæ. Plants of the protea tribe also add to the extraordinary variety in the vegetable physiognomy of that region.

Of the characteristic African plants, the date-tree is one of the most important, as it is likewise among the nearly one thousand different species of palms. It furnishes, as it were, the bread of the desert, beyond which it occurs only in Western Asia, wherever a similar dry and hot climate prevails. This tree requires a sandy soil, and springs must not be absent. The dates furnish food not only for man, but for the camel and the horse. For the latter purpose the stones are used in many parts, and are said to be more nourishing than the fruit itself. The Arabs make a great variety of dishes of which dates form the chief part. Of the sap of the tree palm-wine is prepared, and the young leaves are eaten like cabbage.

In Southern Africa are the extensive miniature woods of heaths, as characteristic as the groves of date-palms in the north. No less than five hundred species have already been discovered. These plants, of which some reach the height of 12 to 15 feet (Erica urceolaris), are covered throughout the greater part of the year with innumerable flowers of beautiful colours, the red being prevalent.

The papyrus is an aquatic plant, having a stem from 3 to 6 feet high. It inhabits both stagnant waters and running streams, and is common in the countries of the Nile, particularly Egypt and Abyssinia. Its soft, smooth flower-stem afforded the most ancient material form which paper was prepared, and for this reason it is one of the noticeable African plants. It has, however, also been used for other purposes; its flowering stems and leaves are twisted into ropes; and the roots, which are sweet, and used as food.^[1]

The following table, compiled from the "synonymic lists of species of mammals" given by Mr Andrew Murray,^[2] affords a general view of the distribution of terrestrial mammals in the different parts of Africa,—the figures denoting the number of species found in each of the divisions, those in the last column being the number peculiar to Africa:—

The order Quadrumana is well represented, more particularly within the tropics, whence they decrease northwards and southwards. The most important members of this family are the antropoid monkeys, the chimpanzee and gorilla, in Tropical and Western Africa. Baboons and mandrils, with few exceptions, are peculiar to Africa. Only a few species of the genus Macacus, which is East Indian, are found in Africa. The only short-tailed species (Macacus Innuus)