1Q The Philippine Jowrval of Scii>nce 



Table I. — Mechanical analyses of soils, etc. — Continued. 



1914 



Source. 



Miscellaneous 



Do 



Do 



Do 



Do 



Do 



Do 



Do— 



Do 



Do... 



Do 



Do -. 



Do 



Do 



No. 



Coarse 

 sand, 

 1-0.5 

 mm. 



Medium 

 sand, 



0.5-O.25 

 mm. 



Fine 



sand, 



0.25-0.10 



mm. 





Per cent. 



Per cent. 



Per cent. 



»9 



0.1 



0.7 



15.5 



"9 





1.3 



14.3 



a 10 



0.5 



1.8 



22.2 



blO 



0.5 



1.3 



19.1 



«11 



0.4 



2.8 



30.7 



oil 



0.6 



2.3 



25.8 



• 12 



0.4 



5.1 



30.5 



bi2 



0.6 



3.9 



25.9 



.13 



8.3 



19.3 



27.8 



613 



7.4 



15.8 



25.3 



a 14 



10.5 



17.9 



23.1 



1.14 



5.5 



16.1 



21.2 



»15 



3.1 



17.1 



28.8 



■■IS 



3.2 



9.9 



28.4 



Very fine 



sand, 

 0.10-0.05 



Silt. 



0.05-0.005 



nmi. 



Per cent. 

 15.2 

 15.3 

 32.7 

 31.5 

 30.2 

 31.4 

 20.7 

 22.5 

 12.1 

 13.9 

 11.2 

 12.5 

 16.6 

 20.6 



Per cent. 



13.2 



13.9 



16.3 



16.3 



7.9 



4.4 



4.7 



5.1 



8.1 



9.2 



8.9 



10.3 



11.2 



13.5 



Fine silt, | Clay less 

 0.05-0.002 than 0.002 



Per cent. 

 34.6 

 35.2 

 18.8 

 21.4 

 20.2 

 24.4 

 19.1 

 21.9 

 15.5 

 18.1 

 16.0 

 18.7 

 15.7 

 19.1 



Per cent. 



20.7 



19.9 



7.7 



9.8 



7.8 



11.1 



19.5 



20.4 



8.9 



10.3 



12.4 



15.7 



7.5 



5.3 



By weight. 



■> By measurement. 



In the table, the numbers Representing the percentages of 

 the coarser and finer fractions are usually, respectively, lower 

 and higher by measurement than by weight. The results by 

 measurement can only approximate those by weight and are 

 satisfactory only for rough work. If it is desired to have a 

 graphic representation of the mechanical structures of the soils, 

 a more accurate and satisfactory way is that suggested by 

 Pratt ^'^ by plotting the mechanical composition by weight of a 

 surface soil and its subsoil, so that not only the relative pro- 

 portion of the different grain sizes is shown, but also the physical 

 composition as a whole. 



Where the data warrant it, we will discuss a region inde- 

 pendently. 



BATANGAS 



We have carried on a rather careful survey of this district. 

 This region has been selected for special study because its 

 agricultural fertility is known. We hope that the data here 

 given will help to establish Philippine soil types, and in time, 

 as the work progresses, it may be possible accurately to state 

 what soils are best suited to a given crop and to interpret the 

 results of any soil in its relation to the ideal soil for a given 

 crop. A study of this kind will also aid in the future manuring 

 and fertilizing of the area. 



A chain of extinct or quiescent and active volcanoes, which 



This Jourtial, Sec. A (1911), 6, 39. 



