7n 



A. BLYTT. 



[No. 1. 



sudden upheaval of the coast in Chili; as also more recently by 

 G. K. Gilbert 1 



In countries where the inner strain has been relieved by 

 great displacements in recent or late geological times, earth- 

 quakes will probably be rare, and less destructive than in coun- 

 tries where there is still a great strain in reserve. And the 

 great rising of Scandinavia has probably relieved the strain to 

 such a degree, that earthquakes are now, with us, neither very 

 numerous nor destructive. 



From the observations made it seems to follow, that earthqua- 

 kes occur more frequently at some times than at others. The 

 celebrated Kant held the opinion, that the moon exerted an 

 influence on the interior of our globe, and on the volcanic 

 forces. Perrey, Volger, Fuchs and Schmidt have published earth- 

 quake-catalogues ; and from the researches made by them it 

 seems to appear that earthquakes are more numerous in 

 the months from October to March than in the months from April 

 to September. As now, when the northern hemisphere has its 

 winter, the earth is in perihelion, it is believed that the greater 

 nearness of the sun produces more earthquakes. NeicmayrHo& 

 not think this opinion is correct, but Beyer* thinks it is. Both 

 agree, however that earthquakes are probably more common 

 during spring-tides. And Neumayr says, that the opinion, of 

 earthquakes being more numerous under low barometric press- 

 ure, appears to him to be relatively well established. 



It is clear, that such slight changes of pressure as those 

 caused by the rise or fall of the barometer, and such small 

 alterations of the forces as are effected by the varying di- 

 stance of the sun and the moon, could not be able to cause 



