The Phenomena of the Atmosphere. 89 



are made a heap of ruins by one of these hurri- 

 canes ; fields of sugar-canes are whirled through 

 the air ; the strongest trees are torn up by the 

 roots and tossed like stubble ; nor can any build- 

 ing be constructed strong enough to afford a 

 shelter from the beating of the storm, and the 

 deluge of wet with which it is accompanied. 

 The island of Jamaica was visited in the year 

 1780 by this fatal calamity, and the damage 

 which ensued is not to be calculated. The hur- 

 ricanes in the West Indies have been attributed, 

 with great probability, to some occasional ob- 

 struction in the usual and natural progress of the 

 equatorial trade winds. 



The harmattan is a wind which prevails oc- 

 casionally during the months of December, 

 January, and February, in the interior parts of 

 Africa, and always blows towards the Atlantic 

 ocean. There are generally three or four returns 

 of it every season; it blows with a moderate 

 force, not quite so strong, indeed, as the sea 

 breeze. A fog or haze always accompanies the 

 harmattan, so that the sun is concealed the greater 

 part of the day, and the largest building cannot 

 be seen at a quarter of a mile distance. The 

 particles which constitute this fog are deposited 

 on the leaves of trees, and on the skins of the 

 negroes, making them appear white. But the 

 most extraordinary property of this wind is its 

 extreme dryness. No dew falls during its con- 

 tinuance (on the average about a week), and the 



