10 Vol. XLIIL, Art. 6. — S. Tsuboi : 



long to the earliest stage. Subsequently, at intervals, repeated 

 extrusion of " black lavas " took place, followed by the ejection of 

 ashes, sands, lapilh, etc. and the extrusion of " gray lavas ". In 

 this way a great cone (the present somma) was built up, but a 

 depression took place at its summit and a central cone appeared 

 after repeated eruptions. 



He divided the volcanic history into two stages : the olkine- 

 bearing stage represented by " Fudeshima lava ", " Okata lava ", 

 and " black lavas " ; and the ol'ivineless stage represented by 

 " gray lavas " and the lavas of the central cone. 



Very recently the same writer'^ advanced the view that the 

 area adjacent to the island is rising, or has risen, more rapidly in 

 tlie east than in the west, thus explaining the asymmetrical form 

 of the volcano, — that the eastern slope is gentler than the western. 



During the eruption in 1912-^4, the island was visited by 

 FusAKicHi Ômoei-\ Seiji Nakamuea'\ Denzô Satô'\ and Yôzô Oka- 

 muea'\ who reported on tlie volcanic eruptions. 



Kyotoku Fujl"^ also visited the actual scene of activity and 

 measured the temperature of flowing lava by m.eans of the Holboen- 

 Kuelbaum optical pyrometer and found it to be from 995"C. to 

 1048^C. in the red hot portion, and 857°C. in the dull portion. 



1) E. Ohashi, " On the Asymmctiical Form of Ôshima," Jovr. Giol. Soc. Tôykô, Vol. XXIV. 

 No. 281, p. 72, 1917 (in Japanese). 



2) "Preliminary Eeport on the Eruption of Volcano Miharn," J{(port Earthq. Invest. 

 Com., No. 81, 1915 (in Japanese). 



3) «The Eruption of Volcano Mihara, (Jshima, Idzu," Tûyô Gaknqei Zasshi, Nos. SGS & 

 369, 1912 (in Japanese). 



4) "The Present Activity of the Mihara Volcano," Jour. Geogr. Tokyo, No. 2S9, 1912. 

 (in Japanese). 



5) "Eeport on the Eruption of Volcano Mihara," Beport Geol. Surv. Japav, No. 48, 1914 

 )in Japanese). 



6) " A Method of Determining the Melting or Solidifying Eange of Temperatures of Lava, 

 by the Measurement of the Electric Condnciivity," Proceedings of (he Tokyo Mathematico- 

 jliysical Society, 2aä Ser., VqI. Yll., No. 14, 1914. 



