THE GREAT ERUPTION OF SAKURA-J[MA IN 1914. 117 



becoming half-cooked while emerging from tlic cool sea-bottom 

 through the upper hot zone. The same tiling liappcned in the 

 Sawaiian eruption of 1902. 



vi. The Lapilli, Ash and Sand. — The recent activity of Sakura- 

 jima was manifested in two ways, beginning with explosions 

 followed by lava efftisions. During the first phase a prodigious 

 amount of disrupted masses was thrown up to the sky, of various 

 size and nature. The western vents were of excessive intensity, 

 projecting blocks of 1 m. or more in diameter, which fell on shore 

 near Yokoyama at a distance of two and a half kilometers from 

 the orifices, and made conical holes in the ground {see p. 66 and 

 PI. V. Fig. 2). The blocks are of juvenile as well as resurgent 

 origin, as will be seen described in the Petkogeaphical Part. We 

 are here mainly concerned with lapilli, sand and ash. 



According to the usage of mining engineers and especially of 

 agrogeologists various grades are established in the order of size 

 in the skeletal portion of soil in mechanical analysis, viz.. 



Size expressed in diameter. Name. 



Minimixm size 10 an Boulder. 



Varying between 10 mi. .ind 10 mm Pebble. 



„ „ 10 mm. „ 1 „ Gravel. 



1 „ „ 0.1 Sand. 



0.1 „ „ U.OI ., Sût. 



Less than 0.01,, Mud. 



Kanai,^^ of the Kagoshima Higher Agricultural College, has 

 treated the loose éjecta ù'om Sakura-jima on the sieve method 

 with the following results : 



a) The ash is composed of hypersthene (not amblystegite), 

 plagioclases and comminuted colorless vesicular glass, of a size 

 less than 0.25 mm., which make up 7 OX to 95% of the whole 

 mass. It is the size which approximately corresponds to that of 



1) Journ. (hoi. Soc. Tokyo, July Number, 1914. 



