PHYSICAL PROPERTIES OF HAWAII SOILS 41 
The percentage of colloids was determined by the water-vapor 
adsorption method. The figures obtained were too high, sometimes 
being abnormally in excess of the figures indicated by the pipette or 
the hydrometer method. This was chiefly due to the amount and 
distribution of the organic material and also to disparity in the 
chemical composition of the inorganic phase. 
The pipette and hydrometer methods of mechanical analysis are 
compared. The detailed hydrometer method, which takes into ac- 
count the specific gravity and temperature, gives a good agreement 
with the pipette method. The rapid hydrometer method, while 
showing greater disagreement with the pipette method than does the 
detailed hydrometer method, is sufficiently useful for the routine 
classification of soils. 
LITERATURE CITED 
(1) Alexander, J. (editor) 
1926-1928. colloid chemistry, theoretical and applied, by selected 
INTERNATIONAL CONTRIBUTORS. 2 V., illuS. New York. 
(2) Alway, F. J. 
1925. THE POWER OP SOILS TO ABSORB WATER FROM AIR. Ill Colloid 
Symposium Monograph v. 3, p. 241-246, illus. New York. 
(3) Anderson, M. S., and Mattson, S. 
1926. PROPERTIES OF THE COLLOIDAL SOIL MATERIAL. U. S. Dept. Agr. Bui. 
1452, 47 p., illus. 
(4) Bennett, H. H., and Allison, R. V. 
1928. the soils of cuba. 410 p., illus. Washington, D. C. 
(5) Bouyoucos, G. J. 
1927. the hydrometer as a new and rapid method for determining 
the colloidal content of soils. Soil Sci. 23 : 319-330, illus. 
(6) 
1928. MAKING MECHANICAL ANALYSES OF SOILS IN FIFTEEN MINUTES. Soil 
Sci. 25: 473^80. 
(7) 
1928. THE HYDROMETER METHOD FOR MAKING A VERY DETAILED MECHANICAL 
analysis of soils. Soil Sci. 26 : 233-238. 
(8) Briggs, L. J., and McLane, J. W. 
1910. MOISTURE EQUIVALENT DETERMINATIONS AND THEIR APPLICATION. 
Amer. Soc Agron. Proc 2: 138-147, illus. 
(9) and Shantz, H. L. 
1912. the wilting coefficient for different PLANTS AND ITS INDIRECT 
determination. U. S. Dept. Agr., Bur. Plant Indus. Bui. 230, 
83 p., illus. 
(10) Burgess, P. S. 
1917. A study of the principal plantation soil types as found on the 
island of Hawaii. Hawaii. Sugar Planters' Assoc. Expt. Sta. 
Bui. 45, 100 p., illus. 
(11) Campbell, J. M. 
1917. laterite: its origin, structure, and minerals. Mining Mag. 
[London] 17: 67-77, 120-128, 171-179, 220-229, illus. 
(12) Charlton, J. 
1927. the mechanical analysis of tropical soils. Agr. Research Inst, 
Pusa, Bui. 172, 9 p. 
(13) Cross, W. 
1915. lavas of Hawaii and their relations. U. S. Geol. Survey Prof. 
Paper 88, 97 p., illus. 
(14) Davis, R. O. E. 
1925. COLLOIDAL DETERMINATION IN MECHANICAL ANALYSIS. JOUI*. Amer. 
Soc Agron. 17: 275-279. 
(15) and Bennett, H. H. 
1927. grouping of soils on the basis of mechanical analysis. U. S. 
Dept. Agr. Circ 419, 15 p. 
