and especially in Scotland, 143 



probably go far to explain the cause of earthquake-shocks, at 

 least in non-volcanic countries. 



But it is better to abstain from speculation on this point, 

 until the results of other observations, no less material, have 

 been considered. 



6. It is very plain that the earthquake-shocks described in 

 the foregoing reports, were manifested in their greatest inten- 

 sity at Comrie, and its immediate neighbourhood. 



There was there greater injury to walls, more displacement 

 of furniture, more loudness and longer continuance of sound, 

 more frequency of shocks, than in any other part of Scot- 

 land. 



In one sense, the shocks may be said to have originated at 

 Comrie, seeing that, at all other places, without exception, 

 where motion was felt or sound heard, both the motion and 

 the sound were perceived to come from that neighbourhood. 



But it is an incorrect form of expression to say, that the 

 shocks originated at any point on the earth's surface. It is 

 plain that they emanated from a point in the interior of the 

 earth, below Comrie, or its immediate neighbourhood. This 

 inference is deducible from those observations which shew, that 

 at Comrie the shock was felt to come perpendicularly up ; and 

 that, at other places, it was felt to come up in a slanting di- 

 rection. 



Thus, at Comrie, one person says of the shock on 23d Oc- 

 tober 1839, " I felt the shock strike the ground perpendicu- 

 larly under my feet three times, like the stroke of a ponder- 

 ous hammer ; and, as far as I can guess, lifted the ground 6 or 

 8 inches.'' Another observer, who was half a mile west of 

 Comrie on the 14th October, says, *' I felt myself lifted, or ra- 

 pidly heaved up and down.'' 



At Blairmore, 10 miles NE. of Comrie, an observer, who 

 felt the shock of 23d October, says that " it produced a sudden 

 and fearful heave upwards, with great unsteadiness or qua- 

 vering motion, and immediately an equally sudden motion 

 downwards, when all appeared to rest as before. The forqe 

 by which the upward motion of the earth was occasioned did 

 not appear to me to act exactly perpendicularly, but rather in 



