April 14, 1870] 
NATURE 
609 
It springs in the Mossamba Mountains, which are on 
the inner borders of Angola and Benguela, its sources 
being close to those of the Quango River, a tributary 
of the Congo. The Kassabi is known to flow north- 
ward as far as the 8th parallel of latitude, and to the 
westward of the capital of the Muata Yanvo, the great 
negro potentate of Central South Africa. Livingstone 
crossed its head on his journey from the Zambesi to 
Loanda, and reports which he collected from the subjects 
of the Yanvo’s kingdom all tend to prove that whatever 
direction its middle course may take, in its lower course 
the Kassabi flows round to westward, and is joined by the 
Quango, The trader Gracga, who penetrated to the Muata 
Yanvo’s capital in 1846, says that the territory of this chief 
is “shut in” by the great rivers Kassabi and Lurua (a 
tributary of the Kassabi),and he affirms that the Kassabi 
has an easterly direction beyond this. 
The Hungarian traveller, Ladislaus Magyar, has pene- 
trated furthest of the three Europeans who have visited 
this region, and his report agrees well with this last. He 
states that the Kassabi, after forming the waterfall of 
Muewe (in about r1° S.) bends gently to northward, but 
further on takes an easterly direction in its lower course, 
and attains a great breadth at the place where it “¢owches 
upon” the extensive lake Mouva, or Uhanja.* Now if we 
turn the Kassabi River eastward in latitude 8° south, in 
agreement with the above description, we find that it 
meets the position which Dr. Livingstone’s letters give 
to Ulenge, the lake or marsh to which the Chambeze 
ultimately flows, and whose waters Livingstone tells us 
by report are “¢aken up” by the Lufira, a “large river 
which by many confluents drains the western side of the 
great valley.” Is not the Lufira, then, the lower course 
of the Kassabi River, and Lake Ulenge of Livingstone, the 
Uhanja of Magyar? If this be the case, the same diffi- 
culties which appear in the way of the Chambeze River 
joining the Nile, hold also against the Kassabi, which 
would seem to join this river at Lake Ulenge. 
Next, the question arises, If these rivers do not form a 
part of the Nile system, where shall we find an outlet for 
them? The answer to this is plainly, in the Congo 
River, 
The Congo was described by the Jesuit missionaries 
who first visited its mouth as “so violent and so powerful 
from the quantity of its waters and the rapidity of its 
current, that it enters the sea on the west side of Africa, 
forcing a broad and free passage (in spite of the ocean) 
with so much violence that for the space of twenty leagues 
it preserves its fresh waters unbroken by the briny 
billows which encompass it on each side.” In the intro- 
duction to his narrative of the British expedition 
to the Congo River in 1816, Tuckey says: “If 
the calculation be true that the Congo at its lowest 
state discharges into the sea two millions of cubic 
feet of water in a second, the Nile, the Indus, and the 
Ganges are but rivulets compared with it, as the Ganges, 
which is the largest of the three, discharges only about 
one-fifth of that quantity at its highest flood.” This state- 
ment may be somewhat exaggerated, but Tuckey actually 
found that this vast river has a width of two, three, or even 
four miles, whilst flowing with a current of two or three 
miles an hour,f and this not at its mouth, but inland 
beyond the mountainous coast region. The northward 
wall-like continuation of the Mossamba mountains, on the 
2oth meridian, to beyond the equator, which Dr. Beke 
supposes to exist,{ would not admit of a longer course 
than about 500 miles for the Congo, and a basin of that 
extent is utterly inadequate to collect and maintain such 
a body of water as that which this river is known to have, 
in a region where the annual rainfall averages only 12 to 
* Magyar's journey in Petermann’s Mittheilungen, 1860. 
+ P. 342 of the Narrative. a * 
t Map to accompany a paper on Dr, Livingstone’s discoveries in “ Illus- 
trated Travels,” Part xy. 
15 inches (Livingstone’s observation at Loanda). Sucha 
vast river cannot be formed in a short course, but must 
have its rise far in the interior of the continent ; and if 
the Kassabi River and its drainage be taken to the Nile, 
where shall we find a sufficiently lengthened course for 
the Congo? 
Tuckey’s unelaborated notes give the opinion that the 
“ extraordinarily quiet rise * of the river (Congo) shows it 
to issue from some lake which had received almost the 
whole of its waters from-the north of the line ;” and again 
be says, “I cannot help thinking that the Congo will be 
found to issue from some large lake or chain of lakes con- 
siderably to northward of the equator.” The reason of 
Tuckey’s supposition that the lakes, which are evidently 
necessary to maintain the volume of water in the Congo 
throughout the year, would be found north of the equator, 
is, that he found the rising of the river beginning on the first 
days of September. At the time of his journey little or 
nothing was known of the times of the rainy seasons in 
Central Africa from actual experience. The observations 
of travellers in the continent since that time have greatly 
increased our knowledge of these seasons, and show 
them to be regulated by the apparent movement of the 
sun between the tropics. An area of low atmospheric 
pressure, with its attendant inflowing winds and rains, is 
constantly moving up and down the part of Africa which 
lies between the tropics, following the vertical sun. If 
every part of Africa were level and equally surrounded by 
water, it would result from this movement of the area of 
low pressure, that a rainy season would begin at each 
point shortly after its latitude had passed vertically beneath 
the sun, and a double rainy season would thus be produced : 
a greater when the low pressure area is moving equator- 
ward in each hemisphere drawing in the sea winds; anda 
lesser when that area is passing north or south outward 
from the equator towards the extremities of the continent, 
inducing rather the land winds, whose moisture is already 
in great part spent. This rule holds good on the low 
coast lands, where other exterior influences do not dis- 
turb the arrangement, but over the high plateau of the 
interior of South Africa, the commencement of the 
rains seems rather to precede than to follow the vertical 
sun, and in the equatorial regions two of the rainy seasons 
are prolonged into one, which lasts for eight months of 
the year. Under the equator at the mouth of the Ogowai 
River, on the west coast, Du Chaillu found the rainy season 
beginning in October; farther inland, in the Fan country, 
the rains set in in September, and in the same latitude, 
between Victoria Lake and Tanganyika, Burton tells us 
that the rainy season begins in August. Between 5° and 
10° south latitude Livingstone’s observation shows that on 
the west coast at St. Paul de Loanda the lesser rains 
begin in November, but in the same latitude in the centre 
of the continent Burton reports the rains of the Tan- 
ganyika basin beginning in September, or two months 
earlier; and Livingstone in his latest journey could not 
proceed to Lake Bangweolo from the Cazembe’s town, 
where he arrived about the middle of September, because 
the rains had set in. Lake Ulenge lies between these 
latitudes, or in about 5° south, so that the rise of the 
waters of the Congo River, if its upper course be through 
this lake, is perfectly explicable, without the necessity 
of taking its reservoir lakes to the north of the equator. 
The lower course of the Congo is probably in a curve to 
north-westward from Ulenge, afterward turning south-west 
to meet the farthest point which Tuckey reached, where it 
was flowing from north-east. The rains would begin to 
fill Lake -Ulenge, as well as the part of its lower course 
below this which is in the centre of the continent, in 
* The maximum rise of the Congo was observed to be only rr feet, gene- 
rally 8 or 9, or lessthan that of perhaps any river of equal magnitude. ‘Chat 
of the Zambezi (above the confluence of the Shiré), a lakeless basin, has been 
found by Livingstone to be as much as 80 feet perpendicularly ; and at 
Khartoum the White Nile rises nearly 18 feet. 
+ As also in the Abyssinian highland, 
