On the Hill of ARTHURS SEAT. . u 



had, in other refpects, the requifites for producing a fimilar 

 effea. 



But all that is known at prefent of electricity, or the ope- 

 ration of infects, is far from being fufiicient to be confidered as 

 the explanation of the appearances in queftion ; for, 



Though the growing plants, or the vegetation of a portion 

 of the living turf, may be killed either by means of electricity 

 or infects, thefe are not the only means by which that effect 

 . may be brought about j at the fame time that this is the only 

 circumftance, in the natural appearance, explainable by the fup- 

 pofed caufe : Therefore, as every circumftance in an appearance 

 muft be properly related to a caufe, by which it is to be ex- 

 plained, fo the many circumftances here found, without any af- 

 finity to, if not inconfiftent with the conjectured caufe, will 

 leave no room for admitting fuch an explanation, according to 

 the prefent view which has been given of the fubject. 



b 2 II. 



