234 EARTHQUAKES. SECT. XXV. 



at once burst out with inconceivable violence. Witness Vesu- 

 vius, on historical record ; and the volcano in the island of St. 

 Vincent in our own days, whose crater was lined with large 

 trees, and which had not been active in the memory of man. 

 Vast tracts are of volcanic origin where volcanoes have ceased to 

 exist for ages. Whence it may be inferred that in some places 

 the subterraneous fires are in the highest state of activity, in 

 some they are inert, and in others they appear to be extinct. 

 Yet there are few countries that are not subject to earthquakes 

 of greater or less intensity ; the tremors are propagated like a 

 sonorous undulation to such distances that it is impossible to 

 say in what point they originate. In some recent instances 

 their power must have been tremendous. In South America, 

 so lately as 1822, an area of 1 00,000 square miles, which is 

 equal in extent to the half of France, was raised several feet 

 above its present level a most able account of which is given 

 in the ' Transactions of the Geological Society,' by an esteemed 

 friend of the author's, the late Mrs. Graham, who was present 

 during the whole time of that formidable earthquake, which 

 recurred at short intervals for more than two months, and 

 who possessed talents to appreciate, and had opportunities of 

 observing, its effects under the most favourable circumstances 

 at Valparaiso, and for miles along the coast where it was most 

 intense. A considerable elevation of the land has again taken 

 place along the coast of Chile, in consequence of the violent 

 earthquake which happened on the 20th of February, 1835. 

 In 1819 a ridge of land stretching for 50 miles across the 

 delta of the Indus, 16 feet broad, was raised 10 feet above the 

 plain. The reader is referred to Sir Charles Lyell's excellent 

 ' Principles of Geology,' already mentioned, for most inte- 

 resting details of the phenomena and extensive effects of vol- 

 canoes and earthquakes, too numerous to find a place here. 

 It may however be mentioned that innumerable earthquakes 

 are from time to time shaking the solid crust of the globe, 

 and carrying destruction to distant regions, progressively 

 though slowly accomplishing the great work of change. A 

 most disastrous instance took place on the 15th of December, 

 1857, in the Neapolitan provinces of La Basilicata and Principato 

 Citeriore, where the destruction was extensive and terrible ; 

 the number of victims, according to the official accounts, being 



