142 ESSAYS AND OBSERVATIONS 



Art. IX. 



Method of detennm'ing the Strength and Di- 

 reSiion of Earthquakes ^ by the late Rev* 

 Z>r Wark, Miniver at Haddington. 



Lisbon, December 26. 17(^4. 



BETWEEN two and three in the mor- 

 ning, I was awaked by a dreadful 

 fhower of rain, accompanied with great 

 blafls of wind, and flafhes of lightning 

 almoft uninterrupted, moft of which end- 

 ed in bright purple. In the forenoon we 

 had the addition of a good deal of thun- 

 der. About eleven the fun fhone forth, 

 and, in lefs than half an hour after, we had 

 a fmart fliock of an earthquake, preceeded 

 by a rumbling noife, and followed by a 

 dead calm of about half an hour. Moft 

 of the people I am acquainted with fay, 

 it was fully as fevere as any one fliock in 

 the great earthquake ; and all of them 

 ipaintain, it was intirely different from 

 any thing of the kind they have felt be- 

 fore. 



