86 LETTERS ON NATURAL MAGIC. 



of the most perfect delineation, clothed in real 

 drapery, and displaying all the movements of life. 

 The apparatus by which such objects may be 

 used, may be called the catadioptrical phantas- 

 magoria, as it operates both by ^reflexion and 

 refraction. 



The combination of mirrors and lenses which 

 seems best adapted for this purpose is shown in 

 Fig. 7, where A B is a living figure placed before 

 a large concave mirror M N, by means of which a 

 diminished and inverted image of it is formed at 

 a b. If P Q is the transparent screen upon which 



Fig. 7. 

 M 



the image is to be shown to the spectators on the 

 right hand of it, a large lens L L must be so 

 placed before the image a 5, as to form a distinct 

 and erect picture of it at A' B' upon the screen. 

 When the image A' B' is required to be the exact 

 size of A B, the lens L L must magnify the small 

 image a b as much as the mirror M N diminishes 

 the figure A B. The living object A B, the mir- 

 ror M N, and the lens L L, must all be placed in 

 a moveable car for the purpose of producing the 



