and especially/ in Scotland. 299 



(at 9 p. M.). It continued to rise till 11 p. m., and then fell 

 again toward 4^^ a. m., according to its usual law."*' 



The French academicians, in relating the earthquakes of 

 Pignerol in 1808, state the following fact, " Le General Me- 

 nou, ayant entendu le 17th Avril, le bruit precurseur d'une 

 secousse, alia de suite examiner le barometre. II vit le mer- 

 cure descendre rapidement a Tinstant de la secousse, et en- 

 suite remonter/'* Mr Darwin mentions, that "just before the 

 earthquake of November 1822, the mercury in the barometer 

 (at Valparaiso) sank beneath the graduated part," and there- 

 fore, as he explains, beneath 26 inches. He adds this remark, 

 that, " considering these circumstances, and especially the 

 unquestionable fact of rain frequently following severe earth- 

 quakes, even at the most unusual seasons, I cannot conclude 

 otherwise than that there exists some connection between the 

 subterranean and atmospheric disturbances, of which we are at 

 present quite ignorant." t 



13. But there are several other meteorological phenomena, 

 indicating a disturbed state of the atmosphere^ which have been 

 frequently observed at or about the time of earthquake-shocks. 



(1.) Gusts nmH Lidls of Wind. — Mr Gilfillan, in reference to 

 the earthquake at Comrie of 10th October 1792, says, " The 

 weather had been with us, as I believe all over Scotland, for a 

 good while past, uncommonly variable and boisterous, and had 

 verged from high gusts of wind to a deep calm, for one or two 

 days before the earthquake. The air was hazy and moist, 

 much like the appearance of the sky before thunder ; and it 

 is a remarkable fact, that the earthquake and its concomitant 

 noises, if I am not mistaken, always happen in calm weather. 

 We have of late also had frequent and heavy rains." J In the 

 register, under date December 1703, it is mentioned, that 

 though a little before the shock there was " a violent storm," 

 it was calm at the moment of its occurrence. Other curious 

 instances of the same general fact are given in the register, 

 under dates 25th February, and May 1793 ; 18th October and 



* Journal de Physique, tome Ixvii. p. 292. 

 t Vogage of the Beagle, vol. ii. p. 433. 



X Memoir of the Rev. Samuel Gilfillan by his son, in which a few ex- 

 tracts ai'o given from Mr GilfiUan'e private journal, p. 1\, 



