EXPERIMENTS, &c. 



as directly expressive of the passions by which 

 they are produced. But the far greater number 

 of them do little more, than merely point out 

 the external cause, or object of the sentiment, 

 which the changes of other parts of the counte- 

 nance declare to exist within us ; or distin- 

 guish certain external appearances depend- 

 ing upon a mental cause, from similar appear- 

 ances arising from a different source. Thus, 

 blushing is often distinguished from an ac- 

 cidental flush of the cheek, by the eye being 

 turned away from the person who occasions it. 

 That many of the expressions, which we at- 

 tribute to the eye, do in fact depend on changes 

 in other ^parts of the countenance, is evident 

 from the alterations we think induced upon it, 

 by the eyelashes falling off from disease, by a 

 slight inflammation of the edges of the eye-lids, 

 without its being communicated to the eye 

 itself, by artificially colouring the eye-brows, 

 and by many other similar circumstances. And 

 how essential to the right understanding of the 

 expressions of the other features, are the mo- 

 tions of the eyes, when conducted with design, 

 and properly directed, must be known to every 

 one, who has attended in discourse to the 

 countenances of very short-sighted people, and 

 more especially to those of persons afflicted with 

 blindness from a gutta serena, in which the eye, 



