Scientific Intelligence. — Meteorology. 179 



the coast under consideration ; but it occurs with peculiar force 

 on what is called the windward coast, especially at Sierra Leone. 

 Its denomination is derived from the Portugese, it being a cor- 

 ruption of the word trueno, which means thunder-storm. Its 

 approach is first discernible by the appearance of a small clear 

 silvery speck, at a high altitude in the heavenly expanse, which 

 increases and descends towards the horizon, with a gradual and 

 slow, but visible motion. In its descent it becomes circumscribed 

 by a dark ring, which extends itself on every side, and as soon 

 as the silvery cloud approaches the horizon, veils it in impene- 

 trable gloom. At the moment the elements seem to have ceased 

 their operations, and the very functions of nature to be para- 

 lysed ; the atmosphere appears to be deprived of the spirit of 

 vitality, and a sensation of approaching suffocation pervades 

 and oppresses the physical system. The mind is wrapped in 

 awe and suspense, but the latter is speedily relieved by the dark 

 horizon being suddenly illuminated by one broad blaze of elec- 

 tric fluid ; peals of distant thunder then break upon the ear, 

 and rapidly approach, and increase in fervency and violence, till 

 the shocks become appaling ; when the thunder is at its loud- 

 est, a tremendous gust of wind rushes with incredible and often 

 irresistible vehemence from the darkened part of the horizon, 

 not rarely in its course carrying away roofs of houses and chim- 

 ney-tops, blowing down or uprooting trees, and laying the stouts 

 est and largest ships on their beam-ends, or sinking them under 

 weigh or at anchor ; and to that succeeds a furious deluge of 

 rain, which falls in one vast sheet, rather than in drops, and 

 concludes this terrible convulsion. The lightning is of the most 

 vivid description, and, contrary to what has been reported of it,, 

 seldom sheet-lightning, but forked and piercing, and often ex- 

 tremely destructive, both to things animate and inanimate. Its 

 apparently doubtful, wild course, is sometimes directed to a large 

 and lofty tree, and the foliage, at the points of contact, is blasted 

 on the instant, the exposed branches are severed from the trunk, 

 and probably the enormous trunk itself is rent to its basis and 

 destroyed. When it comes in contact with a house, it fre^ 

 quently leaves it as great a wreck as ships have been seen to b^ 

 on coming out of a severe action, or after a destructive storm ; 

 and, octasionallv, the building entered by it may happen to re- 



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