8 AGRICULTURE IN THE TROPICS [PT. I 



the shade will in general be 60 80 lower. While in places 

 like Singapore, where the influence of the monsoons is slight, 

 there may be sunshine nearly every day, in places like Ceylon, 

 where they are very pronounced, there may be weeks or even 

 months with hardly a gleam of sunshine during the first onset 

 of the monsoons. 



Rain in the tropics usually falls in violent showers, rapidly 

 raising the levels of the streams, making roads and flowerbeds 

 " swim " with water, and doing a good deal of damage by the 

 silting up of stream beds, washing away of soil, etc. The usual 

 shower varies from 0'03 to 3'0 inches, and it falls in a much 

 shorter time than in Europe. 



Wind in the tropics is, generally speaking, light compared 

 with that found, for instance, in Great Britain. In the monsoon 

 region of South Asia, near the equator the wind blows fairly 

 steadily for six months in one, and six in the other direction, 

 the year being less evenly divided further north. 



In tropical, as in other countries, elevation has a very 

 definite influence upon the climate, the mean temperature 

 and that for practically all hours of the day and night falling 

 about 3'5 4 F. for every 1000 feet of ascent. Thus in Ceylon, 

 to take places with about similar and similarly distributed rain- 

 fall, the mean temperature of various months in Colombo, at sea 

 level, runs from 79 to 83, at Peradeniya, 1560 feet above sea 

 level, from 74 to 79, and at Hakgala, 5600 feet above sea level, 

 from 58 to 63. To dwellers in Europe, where the thermo- 

 meter may easily range from the highest to the lowest of these 

 figures in one day, these may seem trifling differences, but they 

 have a most marked effect upon vegetable life where they go 

 on, as these do, all the year round. Hardly a plant grown in 

 the botanic gardens at Hakgala is the same as in the gardens 

 at Peradeniya, and this is not from any wish to keep the collec- 

 tions dissimilar, but because plants which will grow at the 

 latter place will often not grow at the former except under glass. 

 With the exception of camphor and tea, which come from much 

 further north, and are most accommodating to temperature, 

 but few cultivations can be successfully carried on in both 

 places. 



