STORMS 9 



breeze, blowing towards the land, prevails along tropical 

 coasts (where day and night are nearly equal) during 

 the day, and reaches its greatest force about 2 p.m. 

 The land-breeze, blowing towards the sea, prevails 

 at night, and reaches its greatest force about 1 a.m. 



When the wind attains unusual force, the resulting 

 effects are called storms. Storms may occur in all 

 parts of the world, but they are much more frequent 

 and of greater force in some regions than in others. 

 In some places they have certain marked character- 

 istics, which are often indicated by the local names 

 of the prevailing types. Storms may be referred to 

 two predominant types — namely, squalls and cyclones. 

 The squall is a very brief phenomenon of great inten- 

 sity, with a sudden change of pressure ; very often a 

 sharp rise of the barometer, followed in a few minutes 

 by an abrupt fall, accompanies the most violent gust. 

 Squalls have been very imperfectly studied, and no 

 subject appeals more for investigation. The variety 

 known as the " line-squall " occurs simultaneously 

 along a straight or slightly curved line, more or less 

 at right angles to the direction in which it is propagated. 



Cyclonic storms fall into two classes, the chief differ- 

 ence being in the magnitude of the atmospheric dis- 

 turbance producing them. The more intense are small 

 whirls of air, propagated comparatively slowly over the 

 surface, and giving rise to so powerful an up-draught 

 as to raise a column of water from the sea or any loose 

 material from the land. Such a storm is termed a 

 waterspout or a tornado, and is capable of doing 

 immense damage over a very limited area. 



Certain tropical seas are subject to revolving storms 

 of greater dimensions than waterspouts or tornadoes, 

 but affecting no very large areas of the surface, and 

 moving with such comparative slowness that a ship 



