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PHYSICAL GEOGRAPHY. 



loudest thunder, and, almost directly afterwards, a river, the channel of which had been 

 dry, came down in a stream several feet in depth, and as broad as the whole bed. Hence 

 the. steeple and obelisk form of the rocks, with their naked aspect, which has, not 

 unaptly, been compared to bones stripped of their flesh. 



In the tropical countries of South America, the sea- 

 sonal rains are, perhaps, more intensely copious than 

 in any other part of the torrid zone, and the floods of its 

 rivers are of corresponding magnitude. At the mission 

 of San Antonio de Javita, on the Orinoco, during the wet season, the sun and stars are 

 seldom visible, and Humboldt was told by the padre, that it sometimes rained for four 

 and five months without intermission. The traveller collected there, in five hours, 21 

 lines of water in height on the first of May, and 14 lines on the 3d, in three hours; 

 whereas at Paris there fall only 28 or 30 lines in as many weeks. Humboldt traces the 

 transition from the one great season of drought to that of rain, which divides the year, 

 in an interesting manner, with the atmospheric phenomena which accompany the change. 

 About the middle of February in the valleys of Araqua, he observed clouds forming in 

 the evening, and in the beginning of March the accumulation of vesicular vapours became 

 visible. " Nothing," he remarks, in beautifully graphic style, " can equal the purity of the 

 atmosphere from December to February. The sky is then constantly without clouds, and 

 should one appear, it is a phenomenon that occupies all the attention of the inhabitants. 

 The breeze from the east and north-east blows with violence. As it always carries with 

 it air of the same temperature, the vapours cannot become visible by refrigeration. 

 Towards the end of February and the beginning of March the blue of the sky is less 

 intense ; the hygrometer gradually indicates greater humidity ; the stars are sometimes 

 veiled by a thin stratum of vapours ; their light ceases to be tranquil and planetary ; 

 and they are seen to sparkle from time to time at the height of 20 above the horizon. 

 At this period the breeze diminishes in strength, and becomes less regular, being more 

 frequently interrupted by dead calms. Clouds accumulate towards the south-east, 

 appearing like distant mountains with distinct outlines. From time to time they are 

 seen to separate from the horizon, and traverse the celestial vault with a rapidity which 

 has no correspondence with the feebleness of the wind that prevails in the lower strata of 



