294 



cox. 



September, which is the period of maximimi precipitation in the western 

 zone, but there is no definite dry and wet season ; the explanation is that 

 on account of the direction of the trade winds and the topography of the 

 countr}- the precipitation is much augmented during the months of 

 October to May rather than deficient during the period from June to 

 September, as will be recognized by the excessive annual rainfall. These 

 facts are shown in Tig. 6 which represents graphically the results of 

 the rainfall for Surigao given in Table V. The same inference is drawn 

 from an examination of Table YI which gives the mean humidity by 

 months. Surigao has a humidity for the period of November to May 

 higher than that of any other locality; during the period from June to 

 September which represents the maximum and the minimum respectively, 

 the mean humidities of Manila and Surigao are almost identical. There- 

 fore, the five stations above enumerated fall naturally into the eastern 

 zone with uniformlv distributed rainfall. 





5 



9, 



jAiv. rea. mak. apr. may june july aug. sept. oct. nov. dec. 



Fig. 6. — Mean rainfall in Surigao. 



The humidity or the saturation deficit (100 — humidity) which reg- 

 ulates plant transpiration is only second in importance to rainfall, upon 

 which, at the present time in most places in the Philippines the planter 



