MOTION OF THE EYES IN POETRAITS. 119 



which the position of the face is changed. Thus, 

 in Fig. 25, the pair of eyes are looking intently 

 at the spectator, and the face has a corresponding 

 direction ; but when we cover up the face in Fig. 

 25 with the face in Fig. 26, which looks to the 

 Fig. 25. 



Fig. 26. 



_ 



him by adding suitable features. 



The nose is obviously the principal feature 

 which produces this change of direction, as it is 

 more subject to change of perspective than any 

 of the other features; but Dr. Wollaston has 

 shown by a very accurate experiment, that even a 

 small portion of the nose introduced with the 

 features will carry the eyes along with it. He 

 obtained four exact copies of the same pair of 

 eyes looking at the spectator, by transferring them 

 upon copper from a steel plate, and having added 



