284 EARTHQUAKES. [SECT. xxvi. 



raneous 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 ' Transactions of the Geological 

 Society,' by an esteemed friend of the author's, 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 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 con- 

 siderable 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 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 ; 

 yet the account of this marvellous event was recently brought 

 to Europe by Mr. Burnes. The reader is referred to Mr. 

 Lyell's very excellent work on geology, already mentioned, 

 for most interesting details of the phenomena and extensive 

 effects of volcanoes 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, pro- 

 gressively though slowly accomplishing 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 observations. 

 The shell of volcanic fire that girds the globe at a small 



