16 



A MONTANE RAIN-FOREST. 



There is no other form of precipitation than rain, hail and snow being 

 unknown, although the former occurs at rare intervals in the lowlands. 

 The precipitation is either in the form of light.showers of brief duration 

 or prolonged but gentle downpours particularly characteristic of the 

 May and winter rainy seasons and not uncommon at night during the 

 winter. There is never, so far as I have observed and can learn, the 

 hard downpour of large raindrops characteristic of tropical lowlands. 

 The frequency of showers too light to register 0.01 inch is high, and 

 they are not without influence on the vegetation. Although the number 

 of rainy days is great and the frequency of light showers is high, yet 

 the bulk of the annual rainfall is registered during the prolonged 

 downpours. In the 168 months of 1892 to 1905 inclusive, there were 

 23 (14 per cent) in which 50 per cent or more of the monthly total fell 

 upon one day; 64 (38 per cent) in which it fell upon two days; 45 

 (27 per cent) in which it fell upon three; and 36 (21 per cent) remaining 

 in which it was more evenly distributed. The heaviest single daily- 

 falls of rain at Cinchona were 28.66 inches on May 25, 1898; 11.50 

 inches on August 10, 1903 (accompanying the hurricane which visited 

 the island on that date), and 18.30 inches on November 8, 1909. 



Dew is formed abundantly in open situations on clear nights at all 

 seasons of the year. 



SUNSHINE AND CLOUDINESS. 



No indication of the relative amounts of sunshine and cloudiness 

 is given by the figures exhibiting the number of rainy days, owing to 

 the high frequency of foggy or cloudy days on which there is not an 

 appreciable amount of precipitation. No records of sunshine have 

 been kept at Cinchona by the Department of Public Gardens and 

 Plantations. From November 1905 to March 1906 I kept a rough 

 record of the number of hours of sunshine by observing the time at 

 which it clouded over every day, and by estimation of the number of 

 hours of sun during the part of the day when it is intermittently cloudy. 

 My figures are shown in table 8, expressed in percentages of the total 

 possible hours of sunshine. 



Table 8. — Average percentage of sunshine, Nov. 1905 to Mar. 1908. 



