300 Mr D. Milne 07i Earthquake- Shocks in Great Britain^ 



3d and 30th December 1794 ; November 1795 ; 24th Febru- 

 ary 1799 ; September 1801 ; August 1816 ; and 23d January 

 1834. 



On the 27th August 1834, when a shock occurred, a " whirl- 

 wind'' was remarked. 



(2.) Thunder^ and especially lightning, often precedes shocks. 

 On 10th October 1731, a great flash was seen a minute after 

 one. On 1st July 1747, one was seen at the very moment of 

 a shock. On the 8th March 1750, lightning is stated to have 

 been seen a minute or two before. During the earthquake of 

 18th August 1816, a flash was seen at Montrose immediately 

 after the shock. On the 22d October 1821, when an earth- 

 quake in the Highlands occurred, it is mentioned* that *' the 

 day was rainy and lowering ; and about four o'clock there was 

 a loud and continual peal of thunder, with some vivid flashes 

 of lightning." Other examples will be found under dates 8th 

 October 1731, Feb. 1750, and 23d January 1834. 



These accounts are entirely accordant with the observations 

 which have been made during volcanic eruptions. Thus it is 

 related, that, during the eruption of Kotlugia in 1756, before 

 referred to, the lightning was very violent, and killed several 

 persons.t During the earthquake which destroyed Caraccas 

 in 1812, though the evening was cloudless, there was a con- 

 tinued glare of vivid flashes of lightning, and of repeated peals 

 of subterranean thunder, all of which (including the flashes) 

 seemed to issue from below the horizon.]: Humboldt,§ in de- 

 scribing the phenomena attendant on the earthquake of Cu- 

 mana on 4th Nov. 1799, states, that there was a thunder-storm, 

 and " at the moment of the strongest electric explosion, there 

 were two shocks of an earthquake, which followed at 15" from 

 each other. A few minutes before the first shock, there was a 

 very violent blast of wind, followed by an electrical rain in great 

 drops. The electrometer of Volta was strongly aff*ected. The 

 sky remained cloudy, and the blast of wind was followed by a 



* Edin. Philos. Journ. for 1022, vol. vi. p. 192. 



t Henderson's Iceland, vol. i. p. 314 ? 



I Silliman's Journal for January 1029. 



§ Personal Narrative. English Transl, vol. ii. p. 31C. 



