G2 Proceedings. 



not severe. Nor, in fact, have the earthquakes in Great Britain 

 ever been very severe, that in Essex, before referred to, beiug 

 the most severe of modern times. 



Those countries situated in the vicinity of volcanos are not, 

 as a consequence of such proximity, hable to severe earth- 

 quakes. Shght disturbances of the earth's surface do some- 

 times arise when a volcano is in violent eruption, but those 

 disturbances are usually the effect of detonations in the volcano, 

 and are not strictly earthquakes in the sense in which that 

 phenomenon is usually understood. But it has been observed 

 that when a volcano hitherto in continuous eruption suddenly 

 ceases its eruptive force, a true earthquake not unfrequently 

 follows, and the inhabitants of the district regard this cessation 

 of the eruptive force as a sign that an earthquake may be 

 expected. It seems that the ordinary mode of escape of the 

 internal forces of the earth in that district through the action 

 of volcano being from some cause interrupted, a vent is found 

 in the action of an earthquake. 



In the year 1812 the extensive plains of the Mississippi 

 were subject to earthquakes during the greater part of the 

 whole year, no volcano, however, being nearer than many 

 hundreds of miles. That part of Asia lying between the 

 Euphrates and the eastern shore of the Mediterranean is very 

 subject to earthquakes of great violence, but there is no 

 volcano anywhere near. Copiapo, in South America, so sub- 

 ject to earthquakes, is 250 miles from the nearest volcano. 

 The disastrous earthquakes of Calabria, in 1783, of Eiobamba 

 in the Andes, in 1797, and of Molese in the Kingdom of Naples, 

 in 1805, were not within 100 miles of a volcano. 



Earthquakes are more frequent in countries approximate 

 to the sea than in those countries far inland. Thus on the old 

 Continent, the regions of the north and eastern shores of the 

 Mediterranean, and the north-western coast of Africa are 

 subject to these convulsions. Nearly the whole of the western 

 coast of America from 60° N. lat. to Cape Horn may be 

 regarded as an earthquake district. Many of the islands of 

 ■the Eastern Archipelago, the north-western part of Australia 

 and the northern island of New Zealand, the Japanese Islands, 



