The universal geography : earth and its inhabitants

308 SOUTH AND EAST APRICA.iKisin, cannot prevent the formation of a residuum of saline substances in thishicuslrinc reservoir, whoso waters, according to native report, have a flavour ofsulphur.Cl.IMATi;.To the Usagara Mountains, rising between the phiteau and the seaboard, aremainly duo the contrasts of climate, and consequently of all tlio phenomenadepending on it, including those of the running or stagnant waters. In thisregion of East Africa the moan direction of the winds is normal with the coast.AVhcther the south-east trades are in the ascendant, as is the case during thegreater part of the year, or whether they are succeeded by those of the north-east,as in the month of January, when the whole atmospheric system is shifted southwardswith the course of the sun, or whether the aerial currents are attracted tothe interior of the continent, these currents always set in the direction of thecoast. The rain-bearing clouds are thus arrested by the mountain ranges of theinterior. For the same reason the alternating daily breezes are felt only on themaritime slope. Hence the opposite side facing landwards, as well as the inlandplateaux sheltered from the prevailing easterly winds, arc much farther removedfrom marine influences than might be supposed from their proximity to the IndianOcean.The massika, that is to say, the rainy season, during which the people remain" confined to their houses," generally begins on the coastlands in January, whenthe east winds are displaced by the north-east monsoon. But the heavy downpoursscarcely set in before March or April. After the month of May they falloff, returning again in the ruU season, which lasts from the middle of October tothe end of the year.showers occur.September is the driest month, although even then occasionalIn certain inland valleys opening in the direction of the moisturechargedwinds, it rains throughout the whole year, except perhaps for a fortnightor so in September.Here the massika makes its appearance much sooner than onthe coast, and the mountains are frequently wrapped in dense fog. The totalrainfall certainly exceeds 120 inches on the seaward slope of the Usagara uplands.The same contrast that is observed towards the southern extremity of the continentbetween the Atlantic and Indian Ocean seaboards, is also maintained inthese tropical regions lying between the tenth and sixth degrees of south latitude.At equal distances from the equator both the rainfall and the temperature arehigher on the east than on the w'est coast. According to Ilann, the difference oftemperature under the tenth degree of south latitude, that isabout the Rovuma andCuanza estuaries respectively, is as much as eight degrees Fahrenheit, a contrastwhich must be attributed to the direction of the marine and aerial currents on thetwo coasts. The monsoons on the Atlantic side blow almost constantly from thesouth, and are consequently tempered by the cold Antarctic waters. But on theopposite side of the continent the prevailing winds come from the east, that is byan oceanic basin heated by the vertical solar rays.* The contrast is even greater• Temiieruture of the west coast of Africa, 72^ F. ; temperature of the east coast of Africa, 80° F.