In Benguela the plains are healthy and cultivated. More to the north, one encounters nothing but monotonous savannahs and forests with gigantic trees. The soil, at a great number of points, is saturated with water, and, so to speak, enveloped in a shroud of pestilential vapour, which the breeze never scatters.
The low plains of Biafra and Benin, and especially the Delta of the Niger, are unwholesome, rank, and foul-smelling marshes. In their mangrove swamps lurks fever, and a legion of deadly diseases.
“Macies et nova febrium
Terris incubuit cohors.”—(Horace.)
Until the early years of the present century very little was known of the interior of Southern Africa. At this epoch some native merchants traversed the country from one sea to another—from St. Paul de Loanda to the coast of Mozambique and Zanzibar. This exploit was repeated and outstripped by Dr. Livingstone, who, from 1850 to 1856, accomplished a marvellous journey of six thousand miles, through regions never before trodden by the white man’s foot.
Setting out from Kolobeng, the most advanced of the English missionary stations, he arrived, after having crossed some three hundred miles of a region without water, at the beautiful river Zouga, which issues from the western extremity of Lake Ngami.
“A region of drought, where no river glides,
Nor rippling brook with osiered sides,
Nor sedgy pool, nor bubbling fount,
Nor tree, nor cloud, nor misty mount
Appears, to refresh the aching eye;
But barren earth, and the burning sky,
And the blank horizon round and round.”[81]
Lake Ngami is from 45 to 60 miles long, and from 56 to 110 in circumference. Its direction is N.N.E. to S.S.W. Its southern portion curves westward, and it receives from the north-west the Teoughé. The water, very fresh when the lake is full, grows brackish during the dry season. At the latter period it is very shallow, and at eighteen or twenty miles from the shore canoes can be manœuvred with the help of a pole. The banks are everywhere low. At the west a considerable space, utterly bare of trees, proves that the lake was formerly larger. During the months which precede the arrival of the northern waters, cattle, to quench their thirst, make their way with difficulty through the belt of reeds dried up by the sun. The natives, says Livingstone, who reside on the shores of the lake, tell us that trees and antelopes are carried down by the waters during the annual inundation.
The same traveller informs us that the vast regions lying to the north of the lake at such great distances—regions copiously watered, and deluged every year by the heavy tropical rains—pour towards the south the excess of the waters which saturate their soil; and a certain quantity of these waters, encountering the lake on their way, flow into it. It is in March and April that the inundation begins. The waters, on descending, find the rivers dried up, and the lake itself exceedingly shallow. The rivers in this part of Africa flow in channels capable of containing a far greater volume of water than they generally hold. When looking at them, you might believe yourself in some desolated Oriental garden where all the irrigating canals still exist, but where the dams permit only a mere thread of water to take its course.
“The water,” adds Livingstone,[82] “is less absorbed by the earth than lost between banks too wide apart, where the air and the sun evaporate them. I am persuaded that there is not in the whole of this country a river which loses itself amid the sands.”
The country situated to the north is exceedingly level for some hundreds of miles, and abundantly provided with lakes and rivers, which the slightest undulations of the soil divert into innumerable windings. The plain is alternately covered with sombre thickets, lofty forests, and dense herbage. On the banks of some rivers this herbage assumes gigantic proportions, and by its tenacity opposes an effectual barrier to animals. In many places the wide green pastures are enlivened by large herds of cattle, which the natives breed. The land of the Barotses possess immense prairies of this description, the home of numerous herds of elephants. But this richness of the soil is counterbalanced by the insalubrity of the climate. These vast, periodically flooded surfaces become, when the waters recede, the nurseries of deadly fevers, and other formidable maladies, whose destructive influence extends to a great distance.