BAEOMETEICAL FLUCTUATIONS AND EARTHQUAKES. 267 



1755 and 1836, thirteen of these were local shocks, of 

 which eight were accompanied with sudden changes of pres- 

 sure. Of the remaining nine, which were only felt slightly 

 in Basle, no change in atmospheric pressure was observed. 

 Of thirty-six earthquakes which, between 1826 and 1836, 

 were felt in Switzerland, thirty were chiefly confined to 

 Switzerland, and ten of these occurred with a low or 

 falling barometer. 



Humboldt is of opinion that earthquakes only occur 

 with changes in barometric pressure in those countries 

 where earthquakes are few ; and he gives examples where 

 the regular variations of the barometer have gone on 

 without interruption at the time of earthquakes. 



Frederick Hoffmann, who examined fifty- seven earth- 

 quakes which occurred at Palermo between 1788 and 

 1838, came to the following result : — 



The barometer was 



sinking 



in 20 cases 



»» 



» 



rising . . . 



. in 16 „ 



i> 



>» 



at a minimum . 



. in 7 „ 



»» 



»» 



„ maximum . , 



in 3 „ 



» 



» 



undetermined . 



. in 11 „ 



The observations of M. S. di Eossi apparently show 

 that the earthquakes in Italy chiefly occur with a baro- 

 metrical depression and with sudden jumps in atmospheric 

 pressure. 



Schmidt, who examined the earthquakes of the Orient, 

 which occurred between 1858 and 1873, says that they 

 were rare with a high barometer, but numerous when the 

 barometer was low. 



From an examination of a table of 396 earthquakes 

 (May 8, 1875— Dec. 1881) felt in Tokio, furnished to me 

 by Mr. Aral Ikunosuke, the director of the meteorological 

 department, I obtained the following results : — 

 * Die VulTianischen Erscheimmgen der Erde, p. 419 



