EFFECT OF EARTHQUAKES. 81 



the earth,"* by which tremors may be communicated 

 in all directions through the solid rock. 



The more solid the rocks the more they would feel 

 the jar, and the better able they would be to pass it on 

 to the rocks above, whereas in a bed of loose gravel it 

 would be almost extinguished. 



If a number of ivory balls are placed in a row touching 

 one another, a tap given to the first will be felt by all, and 

 the last, having nothing to keep it in its place, will fly 

 off. In a similar manner a shock of earthquake has been 

 known to be so violent as to send paving-stones flying 

 into the air, with such force that they turned a complete 

 somersault. 



It is often found that an earthquake has caused the area 

 affected by it either to sink or rise, more generally the 

 latter, to the extent of several feet. The memorable earth- 

 quake of 1835, which shook the western coast of South 

 America, raised the land round the Bay of Concepcion 

 two or three feet at one blow, and upheaved a rocky flat 

 off the island of Santa Maria, which was left with its beds 

 of gaping mussels hopelessly stranded, ten feet above high- 

 water mark. 



More havoc, too, was wrought in the island of Quiri- 

 quina by this earthquake than would have been accom- 

 plished by the ordinary wear and tear of a century. Its 

 effects were felt far and wide, and had it occurred in Europe 

 the whole continent, from the North Sea to the Mediterra- 

 nean, would, Mr. Darwin says, have felt the tremendous 



* The greatest depth at which the shock originates appears, according 

 to Mr. R. Mallet, to be forty miles, and the smallest eight. 

 G 



