106 SCIENCE PROGRESS 



resembling that of Kagoshima on January 12 ; and, lastly, on 

 March 21, eruptions occurred in Suwanose-jima. These four 

 volcanoes, together with Kaimon-dake, lie nearly along a 

 straight line, the distances between successive summits from 

 north to south being 28, 29, 31, and 91 miles. And this straight 

 line is nearly at right angles to the line of recent craterlets 

 in Sakura-jima. 



Displacements of the Ground. — Some of the most novel, as 

 well as the most remarkable, of Prof. Omori's observations are 

 those which relate to the more or less lasting movements of the 

 ground. The small tsunami or sea-wave probably pointed to 

 some displacement of the sea-bed. It was noticed also soon 

 after the eruption that the sea-level had undergone a change, 

 a distinct elevation, with regard to the surrounding coast of 

 Kagoshima Bay. For instance, at the spring tide of March 13, 

 the low districts at the south end of Kagoshima were covered 

 with sea-water at high tide. Along the north-western and 

 northern parts of the bay, the relative rise was still greater, 

 embankments and stone walls were damaged at several places, 

 and extensive rice-fields behind them were devastated. Prof. 

 Omori estimates the maximum rise at about 3 ft. at Kago- 

 shima and at about 3! ft. along the northern shore of Kago- 

 shima Bay. The greatest change was that observed in Sakura- 

 jima, on the north coast of which the relative rise of the sea 

 was not less than 6\ ft. 



These changes of elevation, however, were by no means 

 permanent. They reached their maximum about the end of 

 19 14. After this, a decrease set in, and Prof. Omori estimates 

 that, if it should continue according to the law which governed 

 its rate in the early stages, the sea may be only about an inch 

 above its original level after the lapse of forty years. 



As to the cause of the change of level, there can be little 

 doubt. It can hardly be due, as has been suggested, to the 

 heating of the waters of the Bay or to the blocking of the Straits 

 of Seto. Prof. Omori claims that the only efficient cause is 

 the actual subsidence of the surrounding land. That some 

 subsidence might be expected to take place is obvious from the 

 vast withdrawal of material, more than half a cubic mile, in 

 the form of lava and ashes. 



A more precise conception of the magnitude of the crust- 

 displacements is afforded by a renewal of various lines of level- 



