PHILIPPINE SOILS. 



295 



must rely to maintain the soil moisture, wliich controls absorption. The 

 mean humidity recorded in 16 different parts of the Archipelago is given 

 in the following table. 



Table VI.— Mean humidity 1904-1909. 

 [Numbers give per cent and are the average of several daily observations.] 



Station, province, island. 



Jan. 



Feb. 



Mar. 



71.4 



70.9 



72.0 



72.7 



71.6 70 3 



76.2 



73.1 



77.7 



79.5 



77.6 



74.5 



77.7 



73.7 



71.8 



82.3 



80.1 



77.2 



80.1 



77.8 



80.7 



85.6 



84.4 



84.0 



86.5 



84.4 



81.8 



82.0 



80.2 



79.7 



87.2 



85.9 



87.5 



82.1 



80.8 



77.8 



81.3 



79.8 



76.7 



80.5 



79.8 



76.9 



7S.1 



77.9 



75.9 



88.5 



90.0 



87.1 



. Apr. May. 



June 



July 



Aug. 



Sept 



Oct. 



Nov. 



Dec. 



Aver- 

 age. 



Vlgan, Ilocos Sur, Luzon__ 

 Dagupan, Pangasinan, 



Luzon 



San Isidro, Nueva Ecija, 



Luzon 



Olongapo, Zambales, Lu- 

 zon 



Manila," Luzon 



Iloilo, lloilo, Panay 



Santo Domingo, Batanes 



Islands, Batan 



Aparri, Cagayan, Luzon ._ 

 Atimonan, Tayabas, Lu- 

 zon 



Legaspi, Albay, Luzon 



Capiz, Capiz, Panay 



Tacloban, Leyte, Leyte ... 



Ormoc, Leyte, Leyte 



Cebu, Cebu, Cebu 



Tagbilaran, Bohol. Bohol . 

 Surigao, Surigao, Minda- 

 nao 



72.2 75.9 



71.3 



66.0 



74.1 

 69.8 

 74.0 



79.8 

 83.6 



80.7 



78.2 



82.8 



77.7 



76.6 



75.3 I 77.7 



75.5 77.6 



76.7 



73.5 



80.3 

 75.8 

 79.3 



80.9 

 83.9 



82.0 



81.0 



80.4 



84.9 

 81.1 

 83.6 



81.4 

 83.9 



85.3 



85.4 



86.1 



87.6 

 84.6 

 84.8 



81.6 

 84.4 



84.1 

 80.1 

 87.8 1 86.9 



78.8 

 S0.6 



87.1 



86.2 



85.2 85.3 



81.3 82.0 

 87.3 



81.3 I 81.2 

 83.3 [ 83.6 

 79.2 I 81.0 

 79.2 



84.5 



83.4 



84.9 



85.7 



86.8 



87.7 

 85.0 

 84.3 



82.1 

 85.0 



83.9 

 81.4 

 87.1 

 78.6 

 83.0 

 79.0 

 77.9 



81.9 



83.6 



85.1 



86.8 



87.1 

 85.7 

 85.1 



81.8 

 86.2 



86.7 

 83.3 

 88.2 

 80.4 

 84.9 

 80.5 

 78.2 



84.0 



78.4 



81.7 



84.5 



82.8 

 83.5 

 84.4 



80.2 

 86.5 



86.9 

 82.5 

 88.0 

 81.4 

 85.4 

 81.7 

 80.6 



85.5 



72.7 



79.0 



80.3 



77.3 

 82.5 

 83.4 



77.4 

 86.1 



87.4 

 82.9 

 86.3 

 82.8 

 84.7 

 81.5 

 80.7 



87.5 



71.6' 77.2 



78.1 



77.9 79. 1 



78.2 

 81.1 

 83.9 



80.9 

 79.3 

 81.9 



78.1 80. 1 

 86.0 85. 



88.1 

 83.2 

 87.6 

 84.1 

 83.4 

 80.5 

 80.8 



89.5 



85.1 

 81.4 

 86.9 

 80.6 

 82.0 

 78.6 

 78.4 



» Normal, 1885-1907, Amiual Bept. Dir. P. I. Weatli. Bur. (1907), 150. 



There is not the same marked variation in the mean humidity of the 

 eastern and western zones, as in the rainfall, but as would be anticipated 

 a close association of the two factors is evident. A high saturation deficit 

 or a falling off in the mean humidity at the first five stations which 

 belong to the western zone is to be noted during the driest months from 

 November to May, for there are no exceedingly rainy days and the 

 moisture in the air is practically all evaporated from the soil. For 

 those stations which belong to the eastern zone the saturation deficit is 

 approximately constant. Since there is less variation in humidity than 

 in rainfall and since the former is largely dependent on the latter and 

 is never low the discussion will be continued with reference to rainfall 

 solely. 



While the above differentiation of the rainfall of the Philippines into 

 two t}^es may not be absolute it is sufficiently accurate to assist in the 

 interpretation of the factors which may infiuence the location of irriga- 

 tion projects and the utilization of soils. With such limited data it is 



104660 2 



