Page:Africa by Élisée Reclus, Volume 4.djvu/474

 888 SOUTH AND EAST AFRICA. Arabia; towards the west, that is, on the terraces and spurs of the Ethiopian highlands, it differs little from that of Shoa. No doubt this region, taken as a whole, is comprised wiihin the influence of the north-east trade winds; but these atmosj)heric currents are frequently deflected from their normal course by the changes of barometiie pressure and temperature, by which they are attracted towards the interior, at one time of the African at another of the Arabian penin- sula. During ihj winter months of the northern hemisphere, from October to March, ihc north-east tiade winds prevuil with most uniformity, blowing at this period mainly parallel with the south-west coast of Somali Land. During the summer months the normal winds are reversed, and the monsoon then veers round towards the north-west, and even the north. Partial shiftings also deflect the atmospheric current in the direction of the west, and they are then accompanied by fogs and vapour-ehurged clouds from the Indian Ocean. The mean winter temperature ranges from about 70° to 79° or 80° F., while that of summer is seldom more than 80^ F. According to Menges, the range for the whole year scarcely exceeds an extreme deviation of 20° F. between the hot and cold sea.sons, at le ist on the Berbera coast.* The regular winter rains, which however are rarelv very copious and attended only by comparatively mild thunder storms, are due to the nortli-east monsoons, which prevail from December to March. As a rule, this season is marked rather by fair weather and clear skies, or else by light clouds, which drift over the coastlands without precipitating any moisture. The true wet season is ushered in with the southern monsoon, which lasts from April to July or August, and which is accompanied by tremendous hurricanes beating furiously against this exposed seaboard. Farther inland the mostly waterless wadys and torrents are now flushed by the tropical downpours, and the arid wastes bloom again for a brief interval. This rainy period, tlie (jn or (jngi of the Somali, is followed by the haga, when the skies are overcast, but no moisture falls, and the surface of the land resumes its usual arid aspect. The cycle of the seasons is completed by the dair, the coldest j)eriod, and the Ji/<i/, a dry month which precedes the return of the heavy rains. These van(»us seasons are delayed in the direction from east to west, that is to say, from the coastlands towards the inland plateaux ; but here the rain-bearing clouds, being arrested by the slopes of the mountains, discharge a more abundant rainfall than along the seaboard. The average annual rainfall on the Shoa highlands is estimated at about forty inches. Flora. In the low-lying districts the soil, being badly watered, is naturally unproduc- tive except in a few favoured localities, where the vegetation vies in splendour and exuberance with that of the Indian seaboard under the same latitudes. But elsewhere the few scanty wells or reservoirs and rivulets of brackish water are msutticicnt to support anything beyond a poor stunted flora scattered thinly over • November 28th, at night, 68° F. April 2nd during the day, 89° to 90° F. *