174 LIGHT SCIENCE FOR LEISURE HOURS. 



loss of life and property in Calcutta harbor, the de- 

 struction on land was greater. A vast wave swept 

 for miles over the surrounding country, embankments 

 were destroyed, and whole villages, with their inhab- 

 itants, were swept away. Fifty thousand souls, it is 

 believed, perished in this fearful hurricane. 



The gale which has just ravaged the Gulf of Mexi- 

 co adds another to the long list of disastrous hurri- 

 canes. As we write, the effects produced by this 

 tornado are beginning to be made known. Already 

 its destructiveness has become but too certainly evi- 

 denced. 



The laws which appear to regulate the generation 

 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 southeast monsoons 

 are at their height. At the same season the African 

 southwesterly 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 aris- 

 ing show their force first at a distance of about six or 



