158 LIGHT SCIENCE FOR LEISURE HOURS. 



and the progress of cyclonic storms are well worthy of 

 careful study. 



The regions chiefly infested by hurricanes are the 

 West Indies, the southern parts of the Indian Ocean, 

 the Bay of Bengal, and the China Seas. Each region 

 has its special hurricane season. 



In the West Indies, cyclones occur principally in 

 August and September, when the south-east monsoons 

 are at their height. At the same season the African 

 south-westerly monsoons are blowing. Accordingly 

 there are two sets of winds, both blowing heavily and 

 steadily from the Atlantic, disturbing the atmospheric 

 equilibrium, and thus in all probability generating the 

 great West Indian hurricanes. The storms thus 

 arising show their force first at a distance of about six 

 or seven hundred miles from the equator, and far to 

 the east of the region in which they attain their 

 greatest fury. They sweep with a north-westerly 

 course to the Gulf of Mexico, pass thence northwards, 

 and so to the north-east, sweeping in a wide curve 

 (resembling the letter U placed thus CH) around the 

 West Indian seas, and thence travelling across the 

 Atlantic, generally expending their fury before they 

 reach the shores of Western Europe. This course is 

 the storm-track (or storm- ^ as we shall call it). Of 

 the behaviour of the winds as they traverse this track, 

 we shall have to speak when we come to consider the 

 peculiarity from which these storms derive their names 

 of 'cyclones' and f tornadoes.' 



The hurricanes of the Indian Ocean occur at the 



