172 
AFRICA SINCE 1888 
standing this lack of long mountain ranges, its average altitude — 
about 2,000 feet — is higher than that of the other continents. 
The country" north of the equator presents a great similarity to 
the country south of it, though the features on the north are on 
a much larger scale. North of the equator is the greater lake 
Chad, south of it the smaller lake Ngami ; north of lake Chad 
is the great desert of Sahara ; south of lake Ngami is the small 
desert of Kalahari. North of Sahara, on the Mediterranean, and 
south of Kalahari, on the Indian ocean, are fertile tracts of 
limited extent, where the rainfall is abundant and vegetation 
flourishes. 
The greater part of the territory between the Mediterranean 
and Sudan and between the Atlantic and the Red sea, and a 
considerable portion south of the Zambesi, comprising nearly 
one-half of Africa, is practically Sahara — that is, a waste or desert. 
The Sahara is a plateau of diversified structure, with hills and 
numerous dried-up water-courses ; regions of dunes or steppes, 
overgrown with alfa, alternating with sandy waste. At sunset 
the temperature falls quickly, causing a difference of one hun- 
dred degrees between day and night. Scattered through the 
desert are about four hundred oa.ses, where the date palm flour- 
ishes. In many places wells have been dug, and great caravans 
follow the line of these oases and wells. The desert of Kalahari, 
in South Africa, is much smaller, has a more temi^erate climate, 
resembles our arid lands, and, like the latter region, is to a large 
extent suitable for the pasturing of cattle. 
Although Africa is about five thousand miles long and four 
thousand five hundred miles wide in the broadest part, stretch- 
ing over seventy degrees of latitude, about two-thirds of its area 
lies within the tropics, with a vertical sun twice a year, giving it 
the hottest climate in the world. The average temperature is 
eighty degrees, while north and south of the tropics the average 
temperature is only ten degrees less. In the tropics the climate 
is so enervating and unhealthy for Europeans that they cannot 
live there more than two or three years, while the same climate 
is most favorable to the negro. 
The Germans occupied the Kamerun, in western Africa, near 
the equator, supposing that a great mountain rising fourteen 
thousand feet directly from the ocean would prove an excellent 
health resort; but the miasmatic vapors ascend the mountain 
slopes and render it an unfit habitation for the European. The 
rainfall in equatorial Africa is most abundant, from sevent\" to 
