288 Mr D. Milne on Ear Ikquakc' Shocks in Great Britain^ 



travelling on foot among the mountains south of Relugas, was 

 first alarmed by a sudden and tremendous "noise of a rushing 

 wind, which came sweeping up the hills like a roar of water. 

 This was instantly followed by the rumbling sound or rhombo, 

 and the ground was then sensibly heaved up and down under 

 his feet." During the earthquake felt in Perthshire, on 1st 

 March 1831, it is related, that the sound resembled a sudden 

 gust of wind, though it was calm at the time. During the earth- 

 quakes at Leicester, on 30th September 1750, and 6th Novem- 

 ber 1764, in Yorkshire in April 1754, the shocks were attended 

 with a rushing sound of the air. During the earthquake in 

 May 1773, it is related, that, though calm and serene, a sud- 

 den gust of wind (apparently) beat against the \Yindows, as if a 

 great quantity of small shot had been thrown against them 

 with violence. In the earthquake of November 1755, it is 

 stated, that, though there was no wind, a whizzing gust in the 

 air was felt immediately before the shock. Another observer 

 says, '' we were all extremely surprised and alarmed at a sud- 

 den blast (rather than explosioii) which burst out instantane- 

 ously, and which seemed to rush through the air with great 

 velocity, and to meet with considerable resistance to its mo- 

 tion ; for it made a whizzing noise as it passed over us." 

 Under date 8th June 1753, it is mentioned that the " shock 

 was accompanied and succeeded by a rushing noise and explo- 

 sion like gunpowder fired in the open air." Farther notices 

 to the same effect will be found under dates December 1703, 

 30th September 1750, 6th November 1764, and September 

 1833. 



That the *' tremblement" of the district affected by a shock 

 must of itself produce a considerable noise cannot be disputed. 

 The jar or tremor in the rocks must communicate a vibration 

 to the air in contact with them. Whether this circumstance 

 will entirely explain the phenomena just related, may fairly 

 admit of a question. What other explanation may be sug- 

 gested, will more properly be afterwards considered, when 

 additional phenomena have been described. 



8. The next circumstance suggested by an inspection of the 

 register, is, that the shocks are more severe and more frequent 

 in certain months of the year, than in others. Of the 139 

 Scotch, and the 116 English earthquakes there recorded, the 



