of " Pele's Hair." a term that is used to describe the hair-like threads 
of lava formed at Kilauea by explosions in the molten lava. Nos. 
506 and 507 are black ash from Haleakala Crater on Maui, while 
Xo. 132 is a sample of black ash from Oahu which had been sub- 
merged at one time by the sea. Xo. 227 is a sample of coral sand from 
the island of Oahu. There is a marked similarity in the composition 
of the lavas from both islands. xV slight variation in the content 
of soda and magnesia is the only perceptible difference. The same 
is also true of the volcanic ash from different sources, except that 
potash should be included as one of the variable constituents. The 
coral sand contains 92.4 per cent of carbonate of lime. The impor- 
tant silicates occurring in the lavas include the pyroxenes, amphi- 
boles, and soda-lime feldspars, while the ash contains more or less 
magnetic iron oxid. 
The primary agent of disintegration in Hawaii is weathering. 
However, the climatic factors influencing decomposition vary so 
widely even in adjacent districts that the soils formed are far from 
uniform in composition or properties. Eainfall varies from a frac- 
tion of an inch to over 200 inches per annum, hence there are humid, 
dry, and even arid districts. Temperature changes, while not rapid, 
vary from the tropical heat to temperate conditions, with snow at 
times in the higher mountains. Again there must be included as 
an agent of disintegration the trade winds which play no small part 
in the transportation of soil grains. The process of lava disintegra- 
tion is generally referred to as laterisation, but in certain of the 
districts submersion by the sea following their formation has ma- 
terially influenced the disintegration of the laterite and the com- 
position of the soil. 
Since practically all the known weathering agents are concerned 
in the formation of Hawaiian soils, acting either separately or in 
different combinations, it is not surprising that the types vary so 
greatly in closely situated districts. 
CHANGES DURING DISINTEGRATION. 
In a previous publication of this station 1 analyses are given show- 
ing the effects of disintegration on the composition of lava during 
the process of soil formation. These analyses are reproduced here 
in order to show more clearly the relation between the composition 
of the soil particles and the original lava. 
1 Hawaii Sta. Bui. 2G (1912). 
