EARTHQUAKES. 253 



substratum, there resulted a destructive shock to all 

 objects houses, trees, or living creatures upon the 

 shaken plains. One may illustrate the nature of the 

 shock as follows: Suppose a small table-cloth to be 

 lying on a large table with raised edges, and that a 

 variety of objects stand upon the cloth. Then, if the 

 table be shaken with a gradually increasing violence, 

 these objects may continue in safety, provided the 

 motion is so managed that there is no abrupt change 

 of direction, and no sudden increase or diminution of 

 velocity. If the motion of the table be suddenly 

 checked, the cloth would not immediately lose its 

 motion, but would slide till it was stopped by the 

 raised edge of the table; and objects on the cloth 

 would move with it, until its motion was checked, when 

 they would receive a shock more likely to be destruc- 

 tive than any which had been communicated to them 

 while the motion of the table continued. And just as 

 such a cloth would ' rumple up,' as soon as the motion 

 of one end was checked, so the soil of the Calabrian 

 plains was found to be in some parts abnormally raised, 

 in others as strangely depressed. 6 In the town of 

 Terranuova,' says Sir Charles Lyell, ' some houses were 

 seen uplifted above the common level, and others ad- 

 joining sunk down into the earth. In several streets 

 the soil appeared thrust up, and abutted against the 

 walls of houses : a large circular tower of solid masonry, 

 part of which withstood the general destruction, was 

 divided by a circular rent, and one side was upraised, 

 and the foundations heaved out of the ground.' 



