CLIMATE. 141 



lie within the tropics, the sun's rays maintain their intensity throughout the year, 

 the discrepancies between winter and summer being very slight, and due mainly to 

 the purity of the air and density of the clouds. As in the "West Indies and in all 

 countries subject to regular monsoons, the Abyssinian year is regulated by the 

 appearance and disappearance of the rains. 



The rainy season varies in time and duration according to the height, latitude, 

 and position of the various provinces. Some regions have even two rainy seasons, 

 being lands of transition belonging at once to two meteorological domains. The 

 southern Abyssinian uplands have two winters, the first commencing in July, when 

 the sun is nearly vertical above the soil, and ending in September ; the second and 

 shorter falling in January, February, or March, when the belt of clouds formed at 

 the zone of contact between the trade- winds and polar currents is deflected south- 

 wards. In the central region tlie winter, or azmara, commences usually in April, 

 continuing, with a few interruptions, till the end of September ; but at the north- 

 west base of the mountains, in the Bogos, Galabat, Gedaref, and Senaar provinces, 

 this rainy season is broken into two, one beginning in April or May, the other, 

 accompanied by tremendous downpours, lasting throughout the months of July, 

 August, and September. The rains, brought by the wind blowing from the Red 

 Sea or Indian Ocean, fall nearly always in the afternoon, accompanied by tempests, 

 but soon clear off, leaving the sky unclouded during the night and following morn- 

 ing. On the eastern slope of the mountains, however, the seasons are reversed, the 

 rains brought by the north wind falling in winter, which lasts from November to 

 March. 



The African coast of the Red Sea lies within the zone of the Mediterranean 

 winter rains, whilst those of Arabia, the interior of Egypt, and Upper Abyssinia 

 belong to a different climatic system. Certain mountains situated on the boundary 

 of the two zones are alternately beaten by winter and summer rains, and the Abys- 

 sinian shepherds have but to go round the mountain to find, according to the 

 season, the herbage necessary for their flocks or land ready for culture. During 

 this period the air enveloping the lowland plains is excessively damp, the hygro- 

 meter never indicating a less proportion than 60 per cent., while the air of the 

 plateaux is, on the contrary, usually dry. 



In the districts where the annual rainfall has been roughly estimated, it is 

 found to vary from two to three inches yearly. But the discrepancy must be much 

 greater in some upland valleys, where the rainclouds are driven together by the 

 winds. Here hailstorms are very frequent. Floodings are known to be extremely 

 dangerous in valleys surmounted by precipitous and barren rocks ; but on the 

 eastern ledges of the Abyssinian border ranges these sudden deluges rushing 

 through steeply inclined watercourses are even more dangerous than elsewhere. 

 During the rainy season all communication ceases between the plateaux, which 

 are divided one from the other by deep kwallas. In the plains of Samhar the 

 caravans, journeying through sand, saline clays, and lavas, are occasionally stopped 

 by the intolerable heat reflected from the earth or rocks, or else by the sandy 

 whirlwinds of the kharif, or colimms of red sand sweeping over the desert. 



