CATADIOPTRICAL PHANTASMAGORIA. 



163 



image of it is formed at a b. If P Q is the transparent 

 screen upon which the image is to be shown to the spec- 

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

 placed before the image a b 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 6 as much as the mirror 

 M N diminishes the figure A B. The living object A B, 

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

 a moveable car for the purpose of producing the variations 

 in the size of the phantasms, and the transformations of 

 one figure into another. The contrivance for adjusting 

 the lens L L to give a distinct picture at different 



Fig. 7. 



M 



distances of the screen will of course be required in the 

 present apparatus. In order to give full effect to the 

 phantasms, the living objects at A B will require to be 

 illuminated in the strongest manner, and should always 

 be dressed either in white or in very luminous colours, 

 and in order to give them relief a black cloth should be 

 stretched at some distance behind them. Many interesting 

 effects might also be produced by introducing at A B fine 

 paintings and busts. 



