>^\v 



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A 



Ul;S 



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m 



r. 





r 1823: 

 1 . 



'^nie- 



lli 



* beach 



'il older 

 >img of 



ction to 



"■> been 



J Andes 

 ^22, tlie 



■om the 

 et :— at 



5 to 6 

 ne eye- 

 let this 

 equal 



fall of 

 iiid for 

 hetical, 

 n sliort 



, ou tbe 



.nilsio^ 

 really 



[1 



1 



area 



{Ion 

 lat 



of 

 to 



tlie 



ji 



le 



lOve- 





Ch. XXVIIL] 



COAST OF CHILI ELEA^ITED. 



97 



must 



of the sea, and after the shocks permanently above it, 

 have contained 57 cubic miles in bulk; which Avould be 



high (or about 



sufficient to form a conical mountain 2 miles high 

 ^s high as Etna), with a circumference at the base of nearly 

 33 miles. We may take the mean specific gravity of the 

 rock at 2 '655, — a fair average, and a convenient one in such 

 computations, because at such a rate a cubic yard weighs 2 

 tons. Then, assuming the great pyramid of Egypt,, if solid, 

 to weigh, in accordance with an estimate before given, 

 6,000,000 tons, we may state the rock added to the continent 



r g 



the Chilian earthquake to have more than equalled 

 100,000 pyramids. 



But it must always be borne in mind that the weight of 

 rock here alluded to constituted but an insignificant part of 

 the whole amount which the volcanic forces had to overcome. 

 The thickness of rock between the surface of Chili and the 



subterranean foci of volcanic action 



may 



leagues deep. Say that the thickness was only 2 mileS;, even 

 then the mass which changed place and rose 3 feet, beino- 



.c miles in volume, must 

 pyramids. 



& 



It may be instructive to consider these results in connection 

 with others already obtained from a different source, and to 

 compare the working of two antagonist forces — the levelling 

 power of running water^ and the expansive energy of sub- 

 terranean heat. How long, it may be asked^ would the Ganges 

 require, according to data before explained (Vol. I. p. 481), 

 to transport to the sea a quantity of solid matter equal to 

 that which may have been added to the land by the Chilian 

 earthquake ? The discharge of mud in one year by the Ganges 

 was estimated at 20,000,000,000 cubic feet. 



estimate 



According to 



require about 4 centuries (or 418 



years) before the river could bear down from the continent 

 nito the sea a mass equal to that gained by the Chilian 

 earthquake. In about half that 



it time, perhaps, the u] 

 amnooter miirht accom 



the operation. 



tutch^ 1819. — A violent earthquake occurred at Cutch, in 

 the delta of the Indus, on June 16, 1819. 



Map 



VOL. IT 



H 



