and especiatli/ in Scotland. 287 



most severe being generally at the commencement of the 

 scries. 



7. The shocks are invariably accompanied by sounds. 



The sounds are of two kinds. One resembles an explosion, 

 which has been variously compared to a discharge of artillery 

 or the blast of a quarry. The other resembles a rushing or 

 whizzing noise. J3oth arc described as being in the atmo- 

 sphere. Some examples of each may now be specially refer- 

 red to. 



(1.) The Explosion. — Dr Stephen Hales relates his sensations 

 during the earthquake of 8th March 1750. He " perceptibly 

 felt his bed heave. There was also a hollow, obscure, rushing 

 noise in the house, which ended in a loud explosion up in the 

 air, like that of a small cantion. The soldiers who were in St 

 James Park, and others who were then up, saw a blackish 

 cloud with considerable lightning, just before the earthquake 

 began. It was also very calm weather."* 



In describing the earthquake of 30th September 1750, the 

 same author states, that persons " were suddenly surprised 

 with an uncommon noise in the air, like the rolling of large 

 carriages in the streets, for about twenty seconds. At the same 

 instant, they felt a great shock or snap, which sensibly shook 

 a punch-bowl and made it ring."t 



Under date 18th November 1756, when an earthquake in 

 Argyleshire is noticed, the shock is stated to have been pre- 

 ceded by a noise like thunder, at a great distance in the air. 

 When the Comrie earthquakes commenced, the inhabitants 

 attributed the noise which they produced to the firing of can- 

 non at Dunira.t Farther illustrations will be found in the 

 register, under dates 8th and 18th March 1750, August 1755, 

 June 1756, March 1792, and August 1834. 



(2.) The Bushing or Whizzing Sound. — Under date in the re- 

 gister of January 1787, it will be seen that a rushing noise in 

 the air preceded the shock, though it was then calm. Sir 

 Thomas Lauder mentions, in his account of the earthquake in 

 1816, that a man, who at the moment of its occurrence was 



* Discourses on Earthquakes, p. 243. t Ibid. p. 263. 



X This circumstance was mentioned in Mr Gilfillan's letter to Sir Thomas 

 Lauder, which was to have b3cn quoted at length ; but in the course of 

 printing this Memoir, the letter has unfortunately been lost or mislaid. 



