THE GREAT EBUrTION OF SAKUKA-JIMA IN 1914. Ill 



from the contact phenomena in limestone which has been influenced 

 b}' injected bathohth of granite, and this temperature is assigned 

 at about 1, 000^-1, 200°C. Wollastonite, a common mineral of 

 contact limestone with granite, also crystallizes below 1,200-. 



The initial temperature of burning lava at the vent of Sakura- 

 jima must lie above 1130 C. for reasons given below. 



The melting or solidifying interval of a chemically decom- 

 posable body is rather long, as in the heterogeneous aggregate of 

 minerals which constitute a rock mass. The melting point at the 

 higher phase of the interval depends upon the acidity of the 

 magma. The modern Japan proper lies within the pétrographie 

 province of andésites (Pacific branch)^\ or the rocks of intermediate 

 acidity. 



As the recent lavas of Sakura-jima have not yet been made 

 the subject of special study, the writer has chosen for comparison 

 the recent lava of Oshima at the entrance of Tokyo Bay. As the 

 physical studies of Japanese lavas are not known in wide circles, 

 and moreover, some results given below are made public for the 

 first time, the writer may be justified in entering somewhat into 

 details, although the lavas under consideration are not those from 

 Sakura-jlma. 



'Jhe Messrs. Fuji und Mizoguchi-^ undertook a melting 



MlHAEA- 



YAMA p(,)int experiment of the la^a welled out in October 1912 



Lava i- i^ 



from the Miliara crater of Oshima Island. The lava is a 

 liyperstheue-andesite of a rather basic nature \\\Û\ SlOoöl%, Al ,0-^22%, 

 Fe,0,lo%, CaO 11%, and 31(j0 2%. The lava in an electric oven 

 began to be plastic from 800 '-860°, ascertained tln'ough electric con- 



1) Koto, ' On the Volcanoes of Japan,' Jour. Geol. Soc. Tokyo, 1916, p. (73). 



2) 'The Melting or Solidifying Eange of Temperature of Lava by Electric Conductivity.' 

 Tokyo Sug.-md. Km, Vol. VII. 1914. 



