THE ERUPTION OF BANDAI-SAX. 119 



a few decimetres to more than a metre in depth ; and they were gener- 

 ally wider at the month than at the bottom. They were found in 

 thousands in the neighbourhood of the crater, as well as on the ex- 

 tensive slopes of bandai and Akahani, a few kilometres away. 



As to the origin of these holes, though they were not perhaps a 

 very important phenomenon of the eruption, it calls for a brief discus- 

 sion, because it has been the subject which has caused a good deal of 

 diversity of opinion and some lively controversy. First of all, they 

 were regarded by some witnesses as miniature craters, each formed by 

 a small explosion of steam. This supposition arose from the facts 

 that several of the holes had the appearance of having been formed by 

 ejections from below the surface, and that in some cases steam had 

 been seen issuing from the holes. But the latter phenomenon was 

 only to be seen near the solfatara adjoining the new crater, from 

 which steam had been issuing for ages; and the appearance of fresh 

 steam-jets in that locality would not be surprising after the convul- 

 sions caused by the catastrophe of the 15th of July. Even, however, 

 if it be allowed that there were a few slight steam explosions in this 

 immediate vicinity, it is, in our opinion, impossible to extend any 

 such hypothesis to the innumerable holes of like appearance that were 

 scattered over the extensive and distant slopes of Obanclai, Akahani 

 &c. Prof. J. Milne on the other hand, regarded the cause of the holes 

 as seismic, but not volcanic, that is to say, he concluded that earth- 

 quake-waves produced at the time of the eruptions, and passing through 

 the soil, caused sub-surface compression and distortion and thereby 

 ejected earthy matter from below, by the spouting action of water. 

 We shall show farther on that the above theory can hardly be applied 

 to any bur a few marshy spots in Numano-taira, to be presently 

 described. 



Others, again, contend that the holes were caused by the fall 



