SOME PHYSICAL FEATURES.
Naturally, in looking upon the contour of a country, we wish to consider its general features, that we may call up a mental picture of it. You know how quickly you can recall an absent friend, if you are familiar enough with his form and features to make a clear mental photograph.
The best authors divide Africa, for convenience, into five different sections: first, the triangular-shaped region south of the Gulf of Guinea and Cape Guardafui; second, the great tract called Soudan, which lies north and northwest of this triangular plateau; third, the Sahara, or Great Desert, which stretches between the Soudan and the cultivated tract that borders the Mediterranean Sea; fourth, the Atlas region, which includes the mountainous countries of Morocco, Algeria, Tunis, and Tripoli; fifth, the region which borders on the Red Sea, and comprises Abyssinia, Nubia, and Egypt.
The first section is mostly a high table-land, with mountains fringing its edges. The Lupata range, which runs parallel with the coast, forms the eastern crest of this table-land. Two snow-clad mountains, Kilimanjaro and Kenia, rise to an elevation of about twenty thousand feet, and mark the greatest height of this table-land in any one section of it.
The table-land does not rise abruptly from the coast. A belt of lowlands lies between the coast and where the elevation begins. These lowlands range from fifty to three hundred miles in breadth.
The eastern extremity of the table-land stretches into the mountainous country of Abyssinia. Its most northern extremity, the summit of Abba Yared, is fifteen thousand feet high.
In the south, the hills of Cape Colony rise by gradual stages from Table Mount to the summits of the mountain ranges in the northern part of the Colony. These summits are estimated to be from seven thousand to ten thousand feet high.
The spaces between these ranges are either valleys covered with shrubs, or broad, elevated terraces. In Cape Colony, which was founded by the Dutch, these valleys have been named kloofs. The terraces have been named karroos. It will be well to remember these names, as we shall find them again in later descriptions of this region.
The second section, Soudan, has sometimes been called Central Nigritia. This tract includes the countries which are watered by the Senegal, Gambia, and Niger, together with the coast of Lower Guinea and the basin of Lake Tchad.
In the western part of this section there is a mountainous table-land. This table-land does not attain any great elevation, but the rivers Senegal, Gambia, and Niger have their rise here.
Many of the older geographers describe a chain of mountains, the Kong, running parallel with the coast of Guinea; but more modern authors, in their descriptions of the edge of the plateau, state that it approaches the coast only at intervals beyond the low delta of the Niger, as far as Cape Verd, and that the supposed Kong Mountains do not exist.
East of the Niger the country is merely hilly, interspersed here and there with very fertile, often swampy, plains. In the basin of Lake Tchad is a vast plain, formed of alluvial deposits. This plain is one of the largest upon the globe, and is noted for its great fertility.
The third section, or Great Desert, extends south nearly to the Senegal, the northern bend of the Niger, and Lake Tchad. Northward, it extends to the Atlas range in Morocco and Algeria. Towards Egypt it reaches nearly to the Mediterranean Sea.
The Sahara is not a vast plain of trackless sand, as we might suppose. The greater part of it, on the contrary, rises into great table-lands. Some of these table-lands contain groups of mountains, rising often to the height of more than six thousand feet. This height is almost equal to that of Mount Washington in New Hampshire, or Mount Katahdin in Maine. It is somewhat greater than that of Mount Marcy in New York, or Mount Mansfield in Vermont.
We must consider the Sahara, then, not a monotonous expanse of burning sand, but a region presenting great variety in its form and characteristics.
From south to north it has an average breadth of about one thousand miles. From the Atlantic Ocean to the western edge of the Nile valley its length is about two thousand miles.
Throughout the entire desert rain rarely falls. Indeed, over a great portion of it there is never a drop of rain. For this reason the land is dry and sterile.
In some portions of the desert there are vast tracts of shifting sand. Frequent and violent winds blow these sands high into the air, and travelers often find themselves suddenly overtaken by one of these sand-storms, to their great discomfort and danger.
Most of us have experienced the discomfort from a sudden cloud of dust and dirt, when the rude winds of March have full force. We can imagine, in a slight degree, the fury of one of these storms of blinding, burning sand.
We can picture the unfortunate bewildered traveler overtaken by one of these storms. Blinded, half-smothered, unable to battle with so unsuspected a foe, he sinks helplessly to the ground. The shifting sands heap themselves over his prostrate form. Alone, unknown, with naught to mark his resting place, he lies buried in the wastes of the Sahara.
Fortunately, all parts of the Great Desert are not so dangerous to life. A large portion, if not the greater portion of it, consists of barren but firm soil. This soil is composed of hardened sand, sandstone, and granite. Quartz rock is sometimes found in small quantities. This portion of the Sahara often rises into ridges, or small hills. These chains of hills are often fully as desolate and bare as the plain from which they rise.
Many of the plains of the Sahara vary from the uniform type. Sometimes on one of them the ground is covered with stones or loose boulders. These are fully as fatiguing to the traveler as the loose, drifting sand. Often these plains are rent by deep chasms. Frequently they are hollowed into great basins.
Into the plains which contain these chasms the rain descends from the gullies of the Atlas mountain system. This sometimes forms streams, which the thirsty sands swallow, or which are quickly evaporated by the burning rays of the sun.
The deeper basins of the Sahara are often of considerable extent. Some of them contain valuable salt deposits.
There are vast tracts, too, of sterile sand, where not even the smallest of plants will take root. In the absence of plant life, animals disappear, and for days the weary traveler may pursue his journey and meet neither beast, bird, nor insect to break the monotony of the dreary waste of sand.
The description of the Sahara by one author is most realistic. "Nowhere are the transitions of light and shade more abrupt than in the desert, for nowhere is the atmosphere more thoroughly free of all vapors. The sun pours a dazzling light on the ground, so that every object stands forth with wonderful clearness, while all that remains in the shade is sharply defined, and appears like a dark spot in the surrounding glare.
"The stillness of these wastes is sometimes awfully interrupted by the loud voice of the simoon. The crystal transparency of the sky is veiled with a hazy dimness. The wind rises, and blows in intermittent gusts, like the laborious breathing of a feverish patient.
"Gradually the convulsions of the storm grow more violent and frequent; and although the sun is unable to pierce the thick dust clouds, and the shadow of the traveler is scarcely visible on the ground, yet so suffocating is the heat, that it seems to him as if the fiercest rays of the sun were scorching his brain.
"The dun atmosphere gradually changes to a leaden blackness, the wind becomes constant, and even the camels stretch themselves upon the ground and turn their backs to the whirling sand storm.
"At night the darkness is complete; no light or fire burns in the tents, which are hardly able to resist the gusts of the simoon. Silence reigns throughout the whole caravan, yet no one sleeps; the bark of the jackal or the howl of the hyena alone sounds dismally, from time to time, through the loud roaring of the storm."
This same author tells us that the sultry breath of the desert is felt far beyond its bounds. It blows over Italy, and crosses even the Alps. Here it rapidly melts the snow of the higher valleys, causing dangerous inundations.
It is no uncommon thing for the dust of the desert to be whirled high into the air and fall upon the decks of vessels crossing the Atlantic far from the coast of Africa. Frequently it flies in clouds over the Red Sea; thus does Nubia greet Arabia.
Considering the scanty vegetation to be found in the Sahara, the scarcity of animal life is not to be wondered at.
The lion, which has been called the king of the desert, contents himself with the borders of his domain. He rarely leaves the wooded mountains of the Atlas region or the fertile plains of the Soudan to wander far into the Great Desert, where there is little water, and only snakes and scorpions are to be found for food in the dry season.
True, among the animals in those sections of the Sahara that are covered with prickly shrubs, may be found the hare and the rabbit, the hedgehog and the porcupine; but the hyena and the jackal, that also haunt these spots, claim these as their booty.
Several varieties of lizards are to be found in the desert. Among them is a large gray monitor and a small white skink. The latter has very short legs. Its movements are so rapid that it seems to swim on the surface, as a fish would in water. Just as its pursuer thinks he has captured it, it disappears, diving under the surface.
It can readily be traced in its retreat and easily taken from the sand. When provisions are scarce, the pursuit of the skink is not considered too much trouble, although its body is so insignificant for food.
There is a proverbial saying that the ostrich needs to drink water only every five days, and could exist much longer without it, if necessary. However this may be, it is certain that this enormous bird penetrates far into the interior of the desert.
The animal life of the Sahara fluctuates from north to south, according to the seasons.
In winter and spring the nomadic tribes wander, with their herds of camels, horses, sheep, and goats, farther into the interior. This is owing to the more favorable conditions; for the heavy rains, falling upon the northern borders of the desert, cover large districts, scorched by the heat of the previous summer, with abundant pasturage and furnish them with a goodly supply of water. As the season advances and the sun gains power, these tribes, with their flocks, retreat again to the borders.
At this favorable season the wild animals—the lion, the gazelle, and the antelope—wander to the sections in the south. Here nature provides the nourishment which the dry summer season could not afford them.
In the southern portions of the Sahara, and in some more northern sections, the tropical rains produce periodical changes in the character of the desert. Under the influence of these rains, the sandy plains soon become clothed with grasses and shrubs.
During the dry season this carpet of green disappears, and the country becomes again an arid tract. Stubbles and tufts of mimosas are the only signs of vegetable life.
The beneficial change from the dry to the rainy season does not always take place. The tropical rains frequently fail to make their appearance in these northern sections, and the hopes of the desert, thirsting for moisture, are doomed to disappointment.