and especiallj/ in Scotland. 271 



these remarks, been unavoidably mixed up ; and on that ac- 

 count, when again adverted to, they will be the more briefly 

 noticed. 



2. Nature of the motion on the earth's surface, produced by 

 the shocks. — There is evidence of three distinct kinds of motion, 

 (1.) an upwardmotion ; (2.) a horizontal motion ; and, (3.) a com- 

 plex or undulating motion. (1.) In illustration of the upward 

 vertical motion, the following account by the Rev. Mr Gilfillan 

 of Comrie, describing the shock of 2d January 1795, may be 

 quoted. The account is taken from the Edinburgh Courant 

 newspaper of 10th January 1795. *' In all the former shocks, 

 the motion was horizontal, and pushed every thing to one side ; 

 but in the late one, the concussion was perpendicular. The 

 house in which I lodge seemed to be lifted or thrown directly 

 upward, and fell down again with a sudden crash ; but as the 

 force was not so violent as to alter the centre^ no harm was 

 done to any thing in it." So also the same intelligent jour- 

 nalist, with reference to a shoclv on the 12th March 1795, notes 

 " Two most alarming shocks, with an interval of 3" interven- 

 ing, accompanied by an uncommonly loud noise. Every thing 

 was heaved upwards^ 



(2.) In illustration of the horizontal motion produced by 

 earthquake-shocks, notice may be taken of a fact mentioned 

 by the Rev. Mr Stukely in his paper on the Philosophy of 

 Earthquakes, that, during the earthquake of 30th December 

 1739 in the West Riding of Yorkshire, " the earth moved 

 backward and forward horizontally, — quivering with recipro- 

 cal vibration.'"' Reference may also be made to the injury to 

 the spire of Inverness Town-Hall, the upper part of which 

 was dislocated by a shock in 1816, and was moved two or 

 three inches towards the NW. The shock was, by other 

 data, ascertained to have come from the NW., whereby build- 

 ings were suddenly pushed horizontally to the SE., and left, 

 as it were, behind them stones and other objects not firmly 

 attached (especially chimney-cans), and to which, therefore, 

 the movement could not be instantaneously communicated. 



(3.) In very many cases, and probably in most, the vertical 

 and horizontal motions of the earth's surface seem to be com- 



