12 
CONCLUSIONS. 
(1) There is a wide variation in the composition of soil particles 
of the same size. from different soil types in Hawaii. 
(2) This variation is due primarily to the number and intensity 
of action of the several weathering agents which are instrumental 
in the disintegration of the lava. 
(3) Iron, titanium, and manganese are present in largest amount 
in the coarse grains. Silica, alumina, and phosphoric acid predomi- 
nate in the finest particles, lime and magnesia in the coarse grains. 
(4) The influence of coagulants upon Hawaiian clays varies with 
the composition of the clay. Those most difficultly coagulable are 
higher in iron and silica than those readily coagulable. 
LIST OF PREVIOUS STATION PUBLICATIONS ON HAWAIIAN SOILS. 
BULLETINS. 
No. 26. The Function and Distribution of Manganese in Plants and Soils. 
No. 28. The Effect of Manganese on Pineapple Plants, and The Ripening of the 
Pineapple Fruit. 
No. 30. The Effect of Heat on Hawaiian Soils. 
No. 31. Rice Soils of Hawaii : Their Fertilization and Management. 
No. 33. The Organic Nitrogen of Hawaiian Soils. 
No. 35. Absorption of Fertilizer Salts by Hawaiian Soils. 
No. 37. Ammonification and Nitrification in Hawaiian Soils. 
No. 38. Effect of Fertilizers on the Physical Properties of Hawaiian Soils. 
No. 39. The Biochemical Decomposition of Nitrogenous Substances in Soils. 
No. 40. The Soils of the Hawaiian Islands. 
No. 41. Phosphate Fertilizers for Hawaiian Soils, and Their Availability. 
PRESS BULLETINS. 
No. 23. The Influence of Manganese on the Growth of Pineapples. 
No. 29. The Management of Pineapple Soils. 
No. 33. A Study of Humus in Hawaiian Soils. 
No. 38. The Use of Dynamite in Farming. 
No. 50. The Effect of Arsenite of Soda on the Soil. 
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