PHILIPPINE SOILS. 



321 



An attempt was made to prepare the sample bj' passing under water through a 

 sieve of 0.25-millimeter mesh as indicated by Schone, but no concordant results 

 were obtained owing to imperfect disintegration of the floccules. Although disin- 

 tegration can not be accomplished by passing through a sieve it can be done 

 satisfactorily by shaking the samples for six hours in 250-cubic-centimeter bottles 

 together with about 75 cubic centimeters of distilled water to which 10 drops of 

 ammonia has been added.^* 



Some of my results in substantiation of these statements are given in Table 

 XIII. 



Table XIII. a — Comparison of the disintegration of soils by shaking and by 

 passing under loater through a sieve. 



[Numbers give percentages.] 



Soil. 



Air-dried sample disintegrated by shaking 6 hours 

 in water. 



Num- 

 ber. 



Color. 



Depth 

 in cm. 



Sand, 1.0 

 to 0.1 

 mm. 



Very fine 



sand, 0.1 



to 0.05 



mm. 



Silt, 0.05 

 to 0.01 

 mm. 



Fine silt, 



0.01 to 

 0.002 mm. 



Clay, 

 <0.002 

 mm. 



Total. 



1 

 2 

 3 

 4 



Light brown 



f 0-15 

 I 0-15 

 ( 0-15 

 1 0-15 

 ( 0-15 

 ( 0-15 

 f 15-30 

 1 15-30 



15.55 

 15.80 

 27.26 



14.23 

 13.00 

 17.66 



22.11 

 23.53 

 12. 38 



33.03 

 32.25 

 28.64 

 29.16 

 34.84 

 37.00 

 34.30 

 36.42 



15.47 

 15.54 

 13.64 

 14.46 

 9.67 



100. 39 

 100.12 

 99.58 



Black 



Brown 



20.74 

 20.40 

 18.97 

 17.60 



17.80 

 16.85 

 16.51 

 14.38 



16.64 



15. 80 



6.81 



9.19 



99.69 



{«) 



33.46 

 23.70 



100. 05 

 101.29 



Soil. 



Air-dried sample disintegrated by passing under water 

 through a sieve.'' 



Num- 

 ber. 



Color. 



Depth 

 in cm. 



Sand, 1.0 

 to 0.1 

 mm. 



Very fine 



sand, 0.1 



to 0.05 



mm. 



Silt, 0.05 

 to 0.01 

 mm. 



Fine silt, 



0.01 to 

 002 mm. 



Clay, 

 <0.002 

 mm. 



Total. 



1 

 2 

 3 

 4 



Light brown 



Black 



Brown 



( 0-15 

 1 0-15 

 ( 0-15 

 I 0-15 

 f 0-15 

 I 0-15 

 j 15-30 

 i 15-30 



34.46 

 22. 44 

 21.00 

 21.24 

 27. 56 



16.71 

 14.90 

 27. 34 

 27. 36 

 18. 54 



36.53 

 31. 65 

 24.71 

 20.51 

 42. .58 



10.48 

 25.96 

 22.56 

 24.55 

 12 



1.-79 

 5.01 

 3.51 

 5.05 

 .85 



99,95 



100.04 



99.12 



98.71 



101. 53 



(') 







36.19 



23.09 



29.43 



8.42 



2.39 



99. .52 



















' ivioisture separately determined and the results calculated to the dry basis. AH clay 

 percentages were obtained by direct determination. 



'' That portion which would not pass the 0.25-millimeter sieve was weighed separately 

 and added to the largest fraction. 



' Subsoil of No. 3. 



A comparison of the relative sizes of the grains given above, shows the mag- 

 nitude of the error when the soil is only passed tfirough a sieve. 



The soil should not be oven dried before it is disintegrated and separated into 

 the individual fractions. The conclusion lias been indicated, though not rigidly 

 drawn, that ''drying a soil at llO'^C does not seriously modify its meflianical com- 



Bitll. U. fi. Dept. Agr., Bur. of Soils (1904), No. 24, 9 and 20. 



