248 EARTHQUAKES. SECT. XXVI. 



ory of man. Vast tracts are of volcanic origin where 

 volcanos 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 100,000 

 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 ' Transac- 

 tions of the Geological Society,' by an esteemed friend 

 of the author, Mrs. Graham, now Mrs. Calcott, who 

 was present during the whole time of that formidable 

 earthquake, which recurred at short intervals for more 

 than two months, and who possesses talents to appre- 

 ciate, and had opportunities of observing, its effects 

 under the most favorable 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 Chili, in consequence of the 

 violent earthquake which happened on the 20th of Feb- 

 ruary, 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; yet the account of this 

 marvelous event was recently brought to Europe by 

 Mr. Burnes. The reader is referred to Mr. L yell's 

 very excellent work on geology, already mentioned, for 

 most interesting details of the phenomena and extensive 

 effects of volcanos 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 accomplish- 

 ing the great work of change. These terrible engines 

 of ruin, fitful and uncertain as they may seem, must, 

 like all durable phenomena, have a law, which may in 

 time be discovered by long-continued and accurate ob- 

 servations. 



