17t^ Volcanoes. 



Lisbon in 1755, various parts of the world suffered under the 

 effect of a similar cause, and within a few succeeding years 

 there happened some of the most violent eruptions that ever 

 afflicted the world. In 1759 the American continent was 

 dreadfully agitated, and Jorullo was in a condition of violent 

 eruption, attended with some most remarkable phenomena. 

 In 1760, Vesuvius opened at once fifteen fissures, and from 

 each vomited immense volumes of lava ; and during the same 

 year Kattlagiaa, in Iceland, broke out with intense parox- 

 ysmal violence, attended with such electric phenomena as were 

 never before witnessed. Thirty days after the destruction of 

 the city of Caraccas, the volcano of St. Vincent became 

 active ; and at the moment it broke forth, a subterranean 

 noise was heard, and the earth was shaken for nearly 2200 

 square leagues^ From these, and numerous other similar 

 facts which we might have selected, it will be evident that 

 earthquake of most alarming character frequently precedes 

 volcanic eruption; but it is only when the activity is very 

 intense that the earth is thus severely shaken. We should, 

 perhaps, be warranted by facts, in stating that the vio- 

 lence of the earthquake is always a criterion to the intensity 

 of the subsequent eruption ; but, however this may be, we do 

 not remember an instance in which volcanic action has not 

 been preceded by earthquake. But earthquake has frequently 

 been unattended with eruption, which may have resulted 

 either from a want of sufficient energy to form a vent, or from 

 the escape of the gases generated by the subterranean heat. 



The violence of an earthquake seldom lasts more than a 

 minute ; but successive shocks are sometimes felt at very short 

 intervals. During the agitation immense chasms are fre- 

 quently formed, through which flames, torrents of water, or 

 dense volumes of gaseous fluid, are thrown. The effects, 

 therefore, of earthquakes, independent of the volcanic action 

 which usually follows, are of a most extensive and dreadful 

 character, and little inferior to the actual ejection of lava. A 

 more appalling description of the consequences of an earth- 

 quake cannot be given than a relation of the circumstances 

 that followed this awful catastrophe in 1638, as observed by 

 Kircher. The father was on his way to Euphemia ; but so 

 violent was the agitation of the water, and so dreadful the 

 noises which seemed to issue from it, that it was found impos- 

 sible to proceed, and he landed with his companions at Lopi- 

 zicum. " Here," he says, " scenes of ruin appeared every- 

 where around me ; but my attention was quickly turned from 

 more remote to contiguous danger, by a deep rumbling sound, 

 which every moment grew louder. The place where we 



