CH. II] CLIMATE 9 



The range of temperature varies according to the slope, to 

 some extent, and on open plains at high elevations there is often 

 a very considerable range of temperature, making the climate 

 very unlike that of places lying upon the slopes quite near by. 

 Thus at Nuwara Eliya in Ceylon, which lies upon an open plain 

 at an elevation of 6200 feet, the thermometer ranges between 28 

 arid 81 during the drier season of the year, while at Hakgala, 

 only six miles off, and 600 feet lower, the extremes are about 

 37 and 79 during the same period, Hakgala lying upon the 

 ordinary mountain slopes. Consequently, perhaps, many Euro- 

 pean plants of the north succeed at Nuwara Eliya, while they 

 merely struggle for life at Hakgala. The greater range of 

 temperature on the plain is probably largely due to l^ie greater 

 radiation that goes on ; and it will be noticed that there is more 

 difference between the minima than between the maxima. 



The character of the soil also has to some extent an effect 

 upon the climate, a sandy soil being liable to get much more 

 heated during the day and cooled at night than a clayey one, 

 so that there is a greater range of temperature upon the former. 

 Drainage of the soil, more particularly in swampy land, thus 

 has a tendency to make the range of temperature greater. 



The effect upon the climate of the clearing of the forests in 

 a country has been a fruitful source of dispute, many of the 

 disputants ignoring the fact that it need not necessarily be the 

 same in all countries. So far as the tropics are concerned, its 

 general effect seems to be to make the climate warmer and drier. 

 In Ceylon, for example, at Peradeniya and Kandy, 1600 feet 

 above sea level, most of the houses built prior to 1850 had fire- 

 places, which are now quite unnecessary, all the forest having 

 been cleared from the neighbourhood, and the mean temperature 

 having apparently risen. In the Federated Malay States, the 

 climate at corresponding elevations appears to be slightly cooler 

 or at least more uniform and damper than in Ceylon, the whole 

 country being much covered with forest. 



The clearing of the forest acts in a disastrous way upon the 

 streams, these being now much exposed, and consequently liable 

 to dry up during dry weather. Most of the streams which rise 

 in the lower parts of the western mountains of Ceylon now dry 



