CHAPTER L.
THE CLIMATE OF AFRICA.
We have considered the climate of Africa but incidentally in connection with the sections which we have viewed. It will be of interest to note the changes in its character in connection with the form of the continent.
While Africa lies almost entirely within the torrid zone, and is therefore the hottest country known to us, yet it presents three great varieties of climate. These correspond with its physical structure. Hence, we find the plateaus, the terraces which lead to them, and the coasts, showing great varieties of climate, though lying very nearly in the same latitude.
The highest temperature is to the north of the equator. In Nubia and in Upper Egypt the intense heat of the sun, acting upon the sands, renders it possible to roast eggs in them; while, along the shores of the Mediterranean the influence of the sea makes the climate much more temperate.
In the vast desert of Sahara, which has an area equal in extent to that of the Mediterranean Sea, and yet is almost destitute of water and well-nigh barren of vegetation, we find the climate showing a uniform yet striking contrast between the heat of the day and the coldness of the night. Towards the south of the Sahara the country is more elevated and consequently somewhat cooler. Some of the more elevated portions near the equator reach the altitude of perpetual snow.
There is no regular fall of snow even in the northern or southern portions of the continent. Radiation of the heat is very great in some parts of Africa, as in the northern sections. The soil of the Sahara, for instance, absorbs heat very rapidly during the day, but during the night it radiates the heat still more rapidly, thus making a great fall in temperature. So rapid is this radiation of heat that ice is said to be formed sometimes during the night when water is left exposed to the atmosphere.
In strong contrast to the hot days and cool nights of the Sahara is the climate of the terraces of Limbu, situated behind the region of the Sierra Leone. Here we find the climate not only temperate but wholesome; while in the region behind the Slave Coast there are beautiful landscapes, abundant springs, new forms of vegetation to delight eye or palate, and an atmosphere as mild and balmy as that of sunny Italy.
In the regions of the Congo the natives call their terrace lands, which are under cultivation and thickly populated, "The Paradise of the World," suggestive of every detail of the beauty of the Garden of Eden, when Adam and Eve were permitted to dwell in it.
The flat coasts of Africa are often flooded over in the rainy season. This renders the climate very oppressive, owing to the humidity of the atmosphere. From the morasses found around the mouths of the rivers a malarious vapor arises, which is most destructive to health. Malarial fever, when it attacks Europeans, is much of the nature of a pestilence in its destruction of life.