Page:Africa by Élisée Reclus, Volume 4.djvu/531

 CLIMATE OF MADAQASOAH. 488 21" F., while at Tamatave, on the sea-coast, it never rises in summer above 93°, and at the island of St. Mary, farther north, above 98° or 100° F.* Madagascar is entirely comprised within the zone of the south-eastern trade winds ; but, owing to the heating of the ground, these winds are generally deflected from their normal course, and usually set in the direction from east to west. Brault's charts, which embody many thousand meteorological observations, nhow that the atmospheric system is most regular during the dry season, that is to say, when the sun stands vertically above the north tropical zone, from April to September. But when it returns to the south, accompaiiiei by its attendant rain-bearing clouds and vjjpours, the winds often change their direction and character. On the coasts of Madagascar they take the form of monsoons, chiefly in the north-west, during the hot, wet seasons from October to Alarch. This is also the period of storms and hurricanes, although the true cyclones, so dangerous in the waters of the Mascarenhas Archipelago, seldom visit the great island. They occasionally, however, reach these latitudes, and in the beginning of 1888 a fierce gale wrecked eleven vessels en the coast of Tamatave.f The summer heats coinciding with the wet season, render a residence on the low-lying east coast extremely dangerous, more especially as this side of the island is more exposed to the vapour-charged clouds rolling up from the Indian Ocean. The ominous title of "graveyard of the Europeans," given to the eastern seaboard of Madagascar, is more particularly justified in the months of January and February, when the sky is overcast with heavy grey fogs. The intermingling of the fresh and salt waters in the estuaries, which receive the discharge of the swollen rivers from the interior, results in a great mortality of the organisms belonging to the two different mediums. The atmosphere, from this and other causes, becomes charged with dangerous exhalations, and to avoid the fevers here endemic, both Europeans and natives hasten to withdraw to the breezy and salu- brious uplands of the interior. But many a traveller has sacrificed his life to his love of science by lingering in the fever- stricken lowland districts. Flora. Like the climatic phenomena, the vegetation is imperceptibly modified with the relief of the land, the different species changing simnltaneously with the general aspect of the indigenous flora. The splendour of the dense tropical vegetation observed by travellers on the well-watered eastern seaboard has led them to suppose that the whole island everywhere possesses a rich soil, clothed with a gorgeous array of verdure. But such is far from being the case. The granitic West Coast Plateaux. Fast Coast. X^o 24' S. Lat ) 4,80U feet high.) 18° 10 S. Lat.) Lowest temperature . 60° F. (July) 42° F (June- August) 59° F. (July) Highest temperature 76° F. (January) 83° F. (November) 93° F. (Dec., January) Difference 26' F. 41° F. 34' F. t Mean rainfall at Tananarjvo (1881 -84), C2 inches. 125— AP
 * 'Winter nnd summer temperatures on both coasts and on the plateaux, according to Grandidier : —
 * (ToUa or Tullear, (Tannnarivo, 18° 55' 8. Lat., (Tamatave,