Page:Africa by Élisée Reclus, Volume 4.djvu/134

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SOUTH AND EAST AFRICA.

Except at some points of the coast, such as Simon's Town and Pieter Maritzburg, the atmosphere is less humid than in West Europe, being extremely dry, especially on the plateaux. Table Mountain frequently presents in summer a remarkable phenomenon, which is due to the greater dryness of the lower aërial strata. The south-east winds, which strike against the huge sandstone block, rise above its south-eastern slopes, and the moisture becoming condensed in the cold atmosphere of the summit, spread out in a dense whitish cloud over the plateau. This "tablecloth," as it is locally called, does not terminate abruptly at the brink of the precipice, but rolls over down towards the city spread out at its foot. Magnificent cascades of sun-lit mist descend some two or three hundred yards, floating like folds of delicate drapery on the breeze, and gradually dissolving in the lower atmospheric regions. Here all the moisture brought by the trade winds becomes absorbed, and except on the cloud-capped summit of the mountain, the whole country remains bathed in sunshine under the bright azure sky. In winter, when the north-west

Fig. 32. — Isothermals of South Africa.

winds prevail, the phenomenon is reversed, and then the billowy mists roll down from the plateau on the opposite side towards Simon's Town.

The rainfall is very unequally distributed on the seaboard and in the interior of South Africa; but on the whole the actual quantity of moisture precipitated is relatively slight, and certainly far less than that of West Europe. Copious rains occur only in a small number of privileged localities, such as the slopes of Table Mountain, where the relief of the land compels the clouds to discharge their contents more freely, Hence in these southern latitudes the year is not divided, as in the equatorial zone, into two well-marked seasons, one rainy, the other completely dry. On the contrary, showers occur everywhere, even on the inland plateaux, throughout the whole year, although usually distributed with a certain regularity from month to month. On the Atlantic side moisture is brought by the returning winds, and consequently abounds mostly in winter from May to August, and especially in the month of July. On the rest of the seaboard between False Bay and