264 EARTHQUAKES. 



Earthquakes and the aurora. — The possible connec- 

 tion between earthquakes and the aurora is a subject 

 which has attracted some attention. Boue has especially 

 made a careful examination of this subject.^ 



He comes to the conclusion that if we compare the 

 monthly periods of earthquake frequency and the aurora 

 there is an agreement between the two. Comparing 

 Perrey's tables of earthquakes from the fourth to the 

 nineteenth century, with tables of the aurora, one-third 

 of both phenomena have occurred, not only in the same 

 day, but often at the same hour. Between 1834 and 

 1847, 457 earthquakes are given and 351 notices of the 

 aurora. 



Out of these : — 



48 occur on the same day, 

 5 occur in the same hour, 

 30 approximate to the same time. 



The nearer together that these phenomena have occurred 

 the stronger have they been. 



Professor M. S. di Rossi brings forward many examples 

 where there has been a coincidence between the appear- 

 ance of the aurora and earthquakes. On 139 nights out 

 of 21 1 days the aurora was seen in some parts of Italy, and 

 ninety-three times earthquakes were felt. On forty-six 

 occasions earthquakes and aurora took place together.^ 

 In considering the probability of a connection existing 

 between these two phenomena, we must bear in mind 

 that the aurora is at no great height above the surface 

 of our earth, and, further, that it can be partially imi- 

 tated. The fact that in earthquake countries, like Japan, 

 the aurora is practically never seen, would indicate that 



» Boue, Parallele der JErdhelen, Nordlicliter und Erdmagnetismus, in 

 Sitz. der K. A. d. Wissensch. 1856, vol. iv, p. 395. 

 2 Meteorohgia Endogena, vol. i. p. 107, &c. 



