326 OF ATMOSPHERICAL CHAP. 10. $ 2. 



and many curious cases are related of persons 

 who have mistaken them for ghosts, and who 

 have literally ran terrified away from their own 

 persecuting shadow. The imagination in these 

 cases often supplies the deficiency of form 

 which is necessary to give consistency to the 

 appearance, and to embody the dusky spectre 

 with the awful form of a ghost. 



The consideration leads directly to the sub- 

 ject of spectral illusions in general, and to the 

 investigation of the physical causes of those 

 phantoms which, in all ages and countries, 

 are recorded as having appeared to certain 

 individuals. We have no good reason for 

 thinking that the apparition which appeared to 

 Brutus, nor the well known fearful spectre which 

 admonished a certain late noble Lord of the 

 time of his death, nor the many inspiring visions 

 of Angels, and Crosses, and the appalling forms 

 of Daemons, which divers persons have seen, 

 had any real existence. Physiology naturally 

 induces us to refer them to the class of occular 

 spectres, and other hallucinations of the organs 

 of sense and their corresponding organs of the 

 brain; and this explanation is rendered more 

 probable, in proportion as we examine into 

 their history, and the health of persons who 



