266 EARTHQUAKES. 



CHAPTER Xy. 



BAROMETRICAL FLUCTUATIONS AND EARTHQUAKES — FLUCTUA- 

 TIONS IN TEMPERATURE AND EARTHQUAKES. 



Changes in the barometer and earthquakes, — Mallet, 

 who collected together a number of examples of earth- 

 quakes which have occurred with a fall of the barometer, 

 and a number which have happened with a rise, concludes 

 that there are as many instances of the one as of the 

 other. At the great earthquake of Calabria, in 1783, the 

 barometer was very low. The earthquake of the Rhine 

 (February 23, 1828) was preceded by a gradual fall of the 

 barometer, which reached its lowest point upon that day. 

 After the earthquake the barometer again rose. The earth- 

 quake of February 22, 1880, in Japan, was accompanied 

 by exactly similar phenomena. Caldcleugh, who observed 

 the heavy shocks in Chili (February 20, 1 835), noticed that 

 on February 17 and 18 the barometer fell 5/10 inches. 

 Similar phenomena were observed before the succeeding 

 smaller shocks. After the shocks the barometer again 

 rose. Principal Dawson, speaking of the earthquakes of 

 Canada, observes that some of the shocks have been 

 accompanied with a low barometer. 



P. Merian, who examined the connection between the 

 Swiss earthquakes and atmospheric pressure, found that 

 out of twenty-two earthquakes observed in Basle between 



