THE ERUPTION OE BANDAI-SAX. 129 



explanation of the phenomenon is that .sparks of fire were produced 

 by stones and rocks striking against each other in the air or falling 

 on a rocky bed. Fragments of rocks are scattered in abundance on 

 the slopes of Obandai. but we could discover nothing to lead us 

 to believe that there had been combustion or any other heat mani- 

 festations. Sensational newspapers in their accounts of the eruption 

 spoke of lurid flames, of a blazing crater and other terrors all probably 

 founded on the peasants' reports of the sparks above mentioned. It 

 very rarely occurs, however, in volcanic eruptions that flames are pro- 

 duced by the burning of gases issuing from craters. Sir W. Hamilton, 

 in describing the Vesuvian eruption of 1779, noted that large vitrified 

 masses (bombs), falling upon the ground, broke into many pieces, and 

 set fire to combustible objects. In this case, however, the fire was 

 produced mainly by the heat of the fused masses, whereas at Bandai 

 the sparks were caused by impact. On the other hand, at the time of 

 the great volcanic eruption of Tarawera, ]\ T e\v Zealand, in 1886, 

 the falling sand was said to have been hot and to have set the trees 

 on fire.* 



As regards unusual optical phenomena, we have heard of one or Optical 

 two only that seem to have been connected with the eruption. Any- p enomena - 

 thing like the twilight-glows, haze, etc, which were such important 

 features after the Krakatoa explosion, could hardly be looked for in 

 this case, which, though exceedingly remarkable in many respects 

 and interesting in the highest degree, was very much inferior in 

 magnitude to the gigantic eruption of 1883 in the Sunda Strait. 

 However, an observer at a place about 87 kilometres or 54 miles 

 E. S. E. from Bandai noticed towards evening on the day of the 

 eruption sparkling rays of red light issuing from the clouds (Report 



* Nature, Vol. 34, 1888, p. 392. 



