206 NICOBAR ISLANDS AND ABORIGINES 



have resulted in great mortality from this cause, although where 

 jungle exists an improvement is said to have taken place when 

 the land has been cleared. 



The average mean annual temperature is about 82.5°, the 

 maximum in the shade between 93° and 94° and the minimum 

 73°. March and April are the hottest months, with means of 82° 

 and 83° and a maximum of 89°, while August to December — 

 when the mean temperature is 79° — is the coolest part of the 

 year. The mean annual temperature at Nankauri is 80°, and 

 while the highest reading recorded is 99°, the lowest is 70°. 

 The mean diurnal range there varies between 9° and 11° 

 only. 



Although the seasons of the monsoons are the same, they 

 are not so well defined among the Nicobars as on the coast of 

 the Bay of Bengal generally ; but heavy rains occur in May, 

 June and July — when the south-west monsoon is at its height — 

 and rains rarely cease until December. March is the driest 

 month, and while from May to December there is an average 

 monthly rainfall of 12 inches, with twenty wet days per month, 

 for the rest of the year the monthly average is only 2.9 inches, 

 with showers on twenty-six days only. 



At Nankauri the mean humidity is 79 per cent, and the 

 annual rainfall no inches; while, as regards the southern group 

 of islands, there is good ground for the belief that much more 

 rain falls, probably not less than an average of 150 inches 

 annually ; this is doubtless attributable to the forest-clad mountains 

 of Great and Little Nicobar. 



The prevailing winds are the monsoons — the south-west from 

 the beginning of May till mid-October, followed by variable 

 winds to the end of the year ; the north-east monsoon from 

 January until April, with an interval of more variable winds 

 before the other sets in. Hurricanes seldom visit the islands, 

 but in March 1892 the central group was subjected to a cyclone 

 which caused much destruction in the forest. During the south- 

 west monsoon frequent thunderstorms and gales of wind occur, 

 especially in the vicinity of Great Nicobar. The north-east 



