As mountain-ranges determine the course of rivers, influence the
rainfall, and temper the climate, we must understand the mountain
system of Africa before we can understand the continent as a whole.
Standing on the citadel at Cairo, and looking south, you see a
sandstone ridge which gradually grows in altitude and width of base as
it runs far away to the south, even to the Cape of Good Hope at the
other end of Africa. Successive ranges of mountains follow the coast,
sometimes near, at others two or three hundred miles inland; the land,
in the latter case, ascending from the coast. The only breaks in this
long chain are where the Zambezi and Limpopo force their way to the
Indian Ocean.
In Abyssinia, on the Red Sea, there is a range of snowy mountains
14,700 feet in height. A few hundred miles to the southeast, and near
Lake Victoria Nyanza, almost under the equator, is another snow-capped
mountain, Kilima Njaro, 18,700 feet high,--the highest mountain in
Africa,--and the mountains of Massai-Land, a continuation of the
Abyssinian Mountains. Another range, apparently an offshoot of the long
range from the Red Sea, forms a wall 100 miles long, and 10,000 feet
high, on the east of Lake Nyassa, separating the waters of that lake
from the Indian Ocean. This range continues to the Zambezi. South of
this river the mountains rise 8,000 to 10,000 feet in height. In Cape
Colony are several ranges of mountains. The highest peak is Compas
Berg, 8,500 feet. In the eastern center of Africa, in the equatorial
region, is an elevated plateau in which is the lake region, then there
is a sudden rise, and a gradual descent towards the Atlantic. There are
few continuous ranges of mountains on the western coast; but at Kamerun
there is a cluster of mountains reaching an elevation of 13,100 feet;
and south of Morocco some of the peaks of the Atlas Mountains reach an
elevation of 12,000 to 13,000 feet, but they have little if any
influence on the rainfall or temperature of the country. It will be
seen from this statement that eastern Africa has high mountain-ranges
rising into an elevated plateau; that the land in Equatorial Africa
gradually descends toward the west and north-west until within one or
two hundred miles of the Atlantic Ocean, when the descent is rapid to
the low and unhealthy coast-lands. Through equatorial Africa runs the
Kongo, the land north of the Kongo gradually rising to an elevation of
about 2,000 feet, and then descending to 1,200 feet at Lake Chad. South
of the Kongo the land rises to an elevation of 3,000 feet, and retains
this elevation far south into the Portuguese territory.
Careful computations have been made to ascertain the average elevation
of the continent. The mean of the most careful estimates is a little
over 2,000 feet. The interior is therefore elevated above the miasmatic
influences of the coast, but exactly what effect this elevation has
upon the temperature can only be ascertained after careful
investigation and a series of observations. North of Guinea and
Senegambia the coast is less unhealthy; but, as the Desert of Sahara
extends to the ocean, the country is of little value, and is therefore
left to the native tribes, unclaimed by Europeans.
In the International Scientific Series it is stated that there are in
Africa ten active volcanoes,--four on the west coast, and six on the
east,--but I have not found any corroboration of this report, and think
it very doubtful if there are any volcanoes now in eruption. The Kilima
Njaro and Kamerun were formerly active volcanoes, for the craters still
exist. In the south the diamond-fields are of volcanic ash formation.