I 



DISTEIBUTION OF EARTHQUAKES IN TIME. 247 



counted, and up to the 24th of February in the following 

 year 451 shocks were felt. 



At St. Thomas, in 1868, 283 shocks were counted in 

 nine and a quarter hours. 



Similar examples might be taken from the description 

 of almost all destructive earthquakes of which we have 

 records. For a large earthquake to occur, and not to be 

 accompanied by a train of succeeding earthquakes, is 

 exceptional. Sometimes we find that a large number of 

 small earthquakes have occurred without a large one 

 being felt. Seismic storms of this description have hap- 

 pened, even in England — for instance, in the year 1750, 

 which appears to have been a year of earthquakes for 

 many portions of the globe. 



In this year, which is known as the 'earthquake year,' 

 shocks were felt in England as follows : On March 14, in 

 Surrey; March 18, in south-west of England ; April 2, at 

 Chester; June 7, at Norwich; August 23, in Lincoln- 

 shire ; September 30, Northamptonshire. 



Synchronis'm of earthquakes. — One of the first writers 

 who drew attention to the fact that two shocks of earth- 

 quakes have been felt simultaneously at distant places 

 was David Milne, who published a list of these occur- 

 rences.^ 



In two instances, February and March 1750, shocks 

 were simultaneously felt in England and Italy. In 

 September 1833 shocks appear to have been simul- 

 taneously felt in England and Peru. These and many 

 other similar examples are discussed by Mallet, who 

 thinks with Milne that these coincidences are in every 

 probability matters of accident. According to Fuchs, 

 Calabria and Sicily appear often to have had earthquakes 

 at the same time, as for instance in 1169, 1535, 1638, 

 * Milne, * British Earthquakes,' Edln. PMl. Journ. vol. xxxi. 

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