THE ERUPTION OF BAJSDAI-SAN. 117 



and steam must have been forced through the U shaped aperture 

 aforesaid. Emerging therefrom at a very high velocity, it swept the 

 whole Biwa ravine which preserved more or less the U shape down- 

 ward, and ravaged the eastern half of the inferior peak Akahani. The 

 evidences of this were clearly apparent on the ground itself, the divi- 

 ding lines between the wind-swept area and the comparative calm which 

 prevailed on either hand having been so sharply defined that the belt of 

 levelled forests and ruined houses was separated by a few metres only 

 from the unharmed areas to the right and left of it. Nothing new 



O CD 



can be claimed for this phenomnon, which is a well-known charac- 

 teristic of certain storms, especially of whirlwinds having their apex 

 near the earth's surface. But its definition on this occasion was in- 

 teresting and well-marked. 



Attempts have been made to associate these particular coups de 

 vent with the moderate northwesterly breeze that prevailed at the 

 time. Dut it is obvious that, though this wind determined the direc- 

 tion of the dust-cloud in the higher regions of the atmosphere, it 

 must have been powerless to contribute sensibly to those intense 

 blasts which descended the Biwa-sawa and swept over the region at 

 the base of the mountain. 



Next let us examine how the wind behaved on the other sides of 

 the volcano. On the east, as before described, Kushiga-mine formed 

 a screening wall which deflected the course of the hurricane; on the 

 west, Yugeta-yama, the part of Kobandai that remained undestroyed, 

 and other ranges of hills arrested the expanding steam and the rush 

 of air, and saved the forests behind. But on the north, there being 

 no obstruction in that quarter, to which moreover the discharges were 

 directed at an inclination to the vertical, the effects were probably 

 tremendous, as was evidenced by the condition of Marumori-yama. 

 Indeed, every spot of the ground to the north of the crater, for several 



