Altogether about three-fourths of the rainfall are thus lost _en route_, and preliminary estimates have determined the mean discharge at about 203,000 cubic feet, which is less than two-thirds of that of the Danube, draining an area scarcely half as large as that of the Russian River.
The volume of water discharged by the Volga, which is at least equal to that of all the other influents of the Caspian together, is sufficient to exercise a considerable influence on the level of the sea. Thus the floods of 1867, the heaviest that had occurred for forty years, raised it by more than two feet, the abnormal excess representing 9,600 billions of cubic feet, or about three times the volume of the Lake of Geneva. On the other hand, the delta steadily encroaches on the sea, though at a rate which it is almost impossible to determine. The sedimentary matter held in solution, estimated by Mrczkovski at about the two-thousandth part of the fluid, continues to form islands and sand-banks, while generally raising the bed of the sea round the face of the delta.
The Volga abounds in fish, and the fishing industry supports a large number of hands. Its lower reaches especially form for the whole of Russia a vast reservoir of food, varying with the seasons, and yielding large quantities even in winter by means of holes broken in the ice at certain intervals.
On the islands of the delta are numerous stations where the fish is cut up, and the roe prepared to be converted into fresh and salt caviar. The _bieluga_ and the sterlet, both of the sturgeon family, attain the greatest size, and are the most highly esteemed, but their number seems to have diminished since the appearance of the steamboat in these waters.
THE CONGO
J. HOWARD REED
The Congo is not only the largest river of the “Dark Continent,” but is second only in point of size and volume to the majestic Amazon of South America. It may, therefore, truly be called the largest river of the Old World.
On referring to the latest maps of Africa we find that the most distant source of the Congo is to be found in the River Chambeze, which rises about midway between the south end of Lake Tanganyika and the north end of Lake Nyasa, at a height of 4,750 feet above the level of the sea. Taking a south-westerly course, this stream flows for some 250 miles, until it reaches a huge depression, where it forms a lake, known to the natives by the name Bangweolo. This lake is about 115 miles long by from forty to sixty miles wide, with an area of from 6,000 to 7,000 square miles. At the south-west corner of Bangweolo the river emerges, having a width equal to that of the Thames at London Bridge, and flows northward under the name of Luapula. About 200 miles further to the north Lake Moero, with an area of about 3,500 square miles, is reached. From the north end of this lake the river again issues, flowing away generally in a northward direction.
At a point about 200 miles from Lake Moero the river, known from the lake to this point as the Luwa, is joined by another stream of much larger size, which rises some 500 miles to the south-west, and is known as the Lualaba. Both these branches of the main river, from their sources to this point, have, of course, had their volumes greatly increased by the innumerable tributary streams flowing into them from the hills and highlands on either side. The two great rivers are now united into one majestic stream, which, bearing the name of Lualaba, continues its flow in a north-north-westerly direction. A little above the point of junction the river receives, on its eastern side, the Lukuga River, which drains the surplus waters of Lake Tanganyika and its tributaries, and augments the mighty volume of the main river.
When we remember that Lake Tanganyika is 400 miles long, from twenty to forty miles broad, has an area of 12,650 square miles, and is fed by tributaries which drain about 70,000 square miles of country, we can form some idea of the enormous body of water which is added to the main stream by the Lukuga River.
About 100 miles to the north of where the Lukuga joins the Lualaba, namely, at the Arab settlement of Nyangwe, the main river is more than a mile wide, with a volume and velocity, according to Stanley, of 230,000 cubit feet of water per second. About 300 miles to the north of Nyangwe are to be found the Stanley Falls, where the river, augmented by the discharged waters of a number of important tributary streams, dashes itself madly down a series of wild rapids and terrible cataracts. These falls extend for a distance of from sixty to seventy miles. From this point the majestic river begins to turn slightly to the westward, and, continuing its course first north-west, then west, and finally south-west--in the form of a gigantic horseshoe--reaches, after a thousand miles’ uninterrupted flow, the open expanse of Stanley Pool. Between Stanley Falls and Stanley Pool the volume of the great river is still further increased by the addition of the waters of a great number of large tributary streams, many of which are themselves extensive rivers, draining many thousands of square miles of territory, and navigable for several hundred miles.
[Illustration: COPYRIGHT BY UNDERWOOD & UNDERWOOD, N. Y. THE CONGO]
Among the great tributaries should be mentioned specially the following; the Aruwimi, noted as the scene of the terrible sufferings of the famous Emin Pasha relief expedition; the Ubangi, or Welle-Makua, which is itself a mighty river, rising away in the “Heart of Africa,” and flowing some 1,200 miles before it joins the main stream. On the south bank may be named the Lubilash or Boloko, navigable for 200 miles; the Lulongo, with its branches--the Lopori and Maringa--navigated for 500 miles by the Rev. George Grenfell; the Chuapa, with its branch, the Busera, up which Mr. Grenfell has also steamed some 500 miles. To these may be added the Kwa, which with its tributaries--the Lukenye, the Kasai, the Sankurn, the Kwango, and a number of others--adds enormously to the volume of the Congo, and affords some 1,500 miles of navigable water.
The great river from Stanley Falls to Stanley Pool has an average width of some five miles, but in places it reaches as much as sixteen miles wide, and is split up into separate channels by large islands, with which its bosom is studded. After passing through Stanley Pool the river ceases to be navigable for about 235 miles--except for one comparatively short break of eighty miles--owing to the angry cataracts known as the Livingstone Falls. Below the falls the river again becomes navigable to the Atlantic Ocean, some 110 miles distant.
The majestic river rushes with such an enormous volume into the open ocean that, for many miles out at sea, its stream can be distinctly traced, and its waters remain fresh, refusing for a long time to become contaminated by the salt of the mighty waste of waters.
The main river and its tributaries have already been explored for at least 11,000 miles. This, of course, gives a length of river banks of no less than 22,000 miles. It can be better grasped what this means when we remember that the whole coast-line of Europe, following every indentation of the shore--from the most northern point of Norway to the spot in the Black Sea where the Caucasus Mountains separate Europe from Asia--is only 17,000 miles, or 5,000 miles less than the total length of river banks past which the mighty Congo continually sweeps. To give another illustration, I may remind you that the circumference of the globe on which we live is 24,000 miles. So that the length of the banks of the Congo--so far as they are at present known--only falls some 2,000 miles short of the total girth of our planet. When the great river becomes more completely known the extent of the river’s banks may probably be found to equal, and very possibly to exceed, the earth’s circumference.
The total length of the main river--omitting the branches--from source to mouth is close upon three thousand miles, equal to the distance from Liverpool to New York.
The area of territory drained is something over 1,500,000 square miles, or equal, roughly speaking, to about one-eight of the whole continent of Africa. It exceeds the total area of India by 200,000 square miles, and would only be equalled by thirty-two Englands. It is needless to quote further figures in order to impress upon us the enormous extent and importance of Africa’s greatest waterway.
The wide-spreading arms of the Congo reach themselves out on all sides to such a distance and extent that the remote headwaters, or fountains, overlap and almost intermingle with the streams which contribute their waters to the other great rivers of the continent. On the north-west we find some of the early streams flowing almost from the same sources which supply tributaries of the Niger and the Shari. In the north-east we find the remote tributaries of the Welle-Makua almost touching those of the Bahr-el-Ghazal, which helps to swell the Nile. The headwaters of the Aruwimi, again, flow from within a few minutes’ walk of where a view can be obtained of the Albert Lake, also belonging to the Nile system. The Malagarazi River, which flows into Lake Tanganyika, and so finds its way to the Congo, rises in the same hills which gave birth to the Alexandra Nile, a western affluent to Lake Victoria. We find, also, many of the great tributaries on the southern bank of the Congo flow from highlands which also pay tribute to streams flowing to the Zambezi.