1909] THEIR CAUSES AND EFFECTS. 241 



often shakes its island, but the disturbances are rarely felt in nearby 

 Sicily. 



The most violent of all recorded volcanic explosions is that which 

 took place in the Strait of Sunda, August 26-27, 1883, when the 

 volcano of Krakatoa was blown to pieces. This outburst destroyed 

 half the mountain and left soundings of 160 fathoms where part of 

 the cone had formerly stood. It produced sea waves that affected 

 tide gauges half way around the world ; air waves that traveled 

 three times around the globe before they ceased to be distinguish- 

 able ; and it threw dust into the air to such a height that it remained 

 suspended for months, but the earthquake shocks produced were 

 strictly local in character and were scarcely felt at Batavia, 90 

 miles from the crater. 



Another of the great explosions of modern times was that of 

 July 15, 1888, when the Japanese volcano Bandai-san, extinct for a 

 thousand years, burst into sudden eruption. In the immediate 

 vicinity of the mountain a moderately severe earthquake shock last- 

 ing about twenty seconds was felt at half past seven in the morning. 

 This was soon followed by additional shocks which culminated 

 when the explosion occurred at the surface, but none was felt 

 severely beyond a limited area. 



Even the eruptions of the Hawaiian volcanoes, Kilauea and 

 Mauna Loa, which are the types of the class of " quiet volcanoes," 

 have sometimes been accompanied by severe local earthquakes. Many 

 eruptions of Mauna Loa, indeed, have been recorded of which the 

 first indication to the inhabitants of the town of Hilo only a few 

 miles away has been the light seen at night reflected in the clouds 

 from the streams of flowing lava. On March 27, 1868, however, 

 there began a series of earthquakes on the southern flanks of the 

 mountain which increased in frequency and intensity for a week 

 and culminated in one of the most severe eruptions known in the 

 history of the volcano, during which a great fissure opened, dis- 

 charging vast quantities of lava that flowed to the sea. 



In the words of Dr. Titus Coan,^ who was on the island at the 

 time : 



''Am. Jour. Sci., II., xlvi., 107, July, 1868. 



PROC. AMER. PHIL. SOC. XLVHI. Ig2 Q, PRINTED SEPTEMBER "J, I909. 



