Analyses of lava and adjacent lava disintegration products. 
Constituents. 
C. 
D. 
G. 
A. 
Disinte- 
B. 
Disinte- 
E. 
Disinte- 
F. 
Lava. 
gration 
products. 
Lava. 
gration 
products. 
Lava. 
gration 
products. 
Lava. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
52.45 
20.29 
52.15 
24.01 
51.98 
26.82 
52.24 
11.49 
37.97 
12.57 
36.27 
15.85 
30.13 
16.00 
3.66 
15.01 
3.36 
14.29 
2.90 
16.86 
3.73 
6.90 
3.22 
7.07 
3.31 
6.84 
3.03 
5.89 
.36 
.19 
.50 
.43 
.92 
.06 
.68 
10.32 
.33 
8.54 
.17 
9.57 
.22 
9.54 
'5.81 
.20 
6.51 
.09 
5.61 
.11 
5.90 
.89 
.25 
.84 
.24 
.97 
.46 
.86 
2.44 
.27 
2.64 
.31 
2.70 
.57 
2.65 
.20 
.78 
.61 
.49 
.51 
.74 
.53 
.38 
.23 
.28 
.34 
.22 
.19 
.11 
4.07 
4.69 
4.07 
4. 84 
1.50 
2.21 
1.50 
1.02 
16.84 
.94 
15.61 
1.04 
18.34 
.54 
H. 
Disinte- 
gration 
products. 
Silica (Si0 2 ) 
Alumina (Al 2 3 ) 
Ferric oxid (Fe 2 03> 
Ferrousoxid (FeO) 
Manganese oxid (M113O4) — 
Lime(CaO) 
Magnesia (MgO) 
Potash (K 2 0) 
Soda(Na 2 0) 
Sulphur trioxid (S0 3 ) 
Phosphorus pentoxid (P2O5) 
Titanic oxid (Ti0 2 ) 
Combined water (H 2 0) 
Per cent. 
32.00 
35.28 
11.80 
1.53 
.08 
.22 
.14 
.30 
.61 
.70 
.04 
2.13 
15.06 
Samples A, B, E, and F are the unaltered lava, while C, D, G, and 
H are the adjacent weathered products or soil formed from the 
respective lava samples. These samples were taken by W. P. Kelley 
from gulches on Oahu, where large exposed lava bowlders have 
undergone weathering to such an extent that samples may be taken 
showing all stages of disintegration from the unaltered lava rock to 
the soil. The alkalis and silica are the most soluble constituents, 
and the former are almost entirely leached away in the process of 
disintegration. The iron is rapidly oxidized to the ferric condition, 
accompanied by a change to red, yellow, or brown soil, depending on 
the state of hydration. 
SELECTION OF SOIL TYPES. 
In selecting soils for this investigation, the policy of selecting all 
the more important soil types, adopted in previous soil studies in 
this laboratory, was pursued. The impossibility of drawing con- 
clusions from results obtained from one type of Hawaiian soil has 
been brought out in previous bulletins of this station. The mechan- 
ical and chemical composition of the soils used are given in the fol- 
lowing tables : 
Mechanical analyses of the soils. 
Soil particles. 
Soil 
No. 164. 
Soil 
No. 291. 
Soil 
No. 292. 
Soil 
No. 339. 
Soil 
No. 392. 
Soil 
No. 428. 
Soil 
No. 448. 
Soil 
No. 474. 
Soil 
No. 547. 
Clay 
Per cent. 
21.10 
51.70 
19.50 
3.79 
} ■» 
Per cent. 
59. 35 
12.13 
7.28 
7.46 
/ .39 
1 
Per cent. 
7.23 
12.41 
8.69 
22.04 
18.75 
20.91 
Per cent. 
19.19 
22.37 
20.42 
18.13 
.22 
.13 
Per cent. 
7.87 
19.36 
13.93 
35. 71 
10.22 
Per cent. 
0.69 
1.76 
5.38 
15.83 
32.82 
13.81 
Per cent. 
6.85 
20.00 
13.45 
16.31 
8.60 
1.94 
Per cent. 
5.24 
24.20 
18.00 
30.70 
} 3.43 
Per cent. 
9.33 
Fine silt 
35.00 
Silt 
30. 15 
Fine sand 
10.75 
Coarse sand 
1.57 
