COMPOSITION OF HAWAIIAN SOIL PARTICLES. 
CONTENTS. 
Page. 
Introduction 1 
Origin of Hawaiian soils 1 
Changes during disintegration 5 
Selection of soil types 6 
Page. 
Composition of the soil particles 8 
Properties of the soil particles 10 
Conclusions 12 
INTRODUCTION. 
One of the primary characteristics of Hawaiian soils is the wide 
diversity of types which makes difficult their classification according 
to the usual methods employed in soil surveys. A wide variation in 
chemical composition, as well as in physical properties, is found 
within very short distances. During a recent investigation in this 
laboratory upon the determination of humus, the character of the 
clay in Hawaiian soils, as regards certain of its properties, was found 
to be radically different from that in mainland soils. Chief among 
these abnormal properties is the incomplete coagulation when coag- 
ulants are added. This is especially true in case of addition of 
ammonium carbonate, which has been successfully used on mainland 
soils for the coagulation of clay in humus extracts. 
This peculiarity of the clay has led to a study of the composition 
of the coagulable and noncoagulable grains and a further investiga- 
tion upon the composition of the clay, fine silt, silt, fine sand, and 
coarse sand separates in the important Hawaiian types of soil differ- 
ing in color, chemical composition, and physical properties. 
ORIGIN OF HAWAIIAN SOILS. 
In order to understand clearly the composition of the soil separates, 
it is necessary to know something of the origin of Hawaiian soils, 
at least the three possible sources from which they may be derived, 
namely, volcanic lava, volcanic ash, and coral sand. As, with the 
exception of small areas near the sea. coral sand need not be con- 
sidered a- a factor in soil format ion in the islands, and as there is 
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