CH. VII] PROJECTION OF IMAGES OF OPAQUE OBJECTS 191 



FIG. 106. NEW MODEL UNIVERSAL BALOPTICON IN POSITION FOR 

 OPAQUE PROJECTION. 



(Cut loaned by the Bausch & Lomb Optical Co.). 



Opaque objects are placed in a horizontal position and the lamp-house, lamp 

 and first element of the condenser are inclined as in fig. 105. The light from 

 the opaque object is reflected upward to the right face of an inclined mirror 

 and from the mirror reflected out through the projection objective, giving an 

 erect screen image. 



When used for lantern slides the lamp-house is horizontal and the horizontal 

 light is reflected upward by the left face of the mirror to the mirror at the left 

 of the lantern-slide attachment. This second mirror reflects the light hori- 

 zontally through the lantern slide. 



the object will be erect in every way (fig. 95-111). (See also the 

 discussion of the reflecting lantern of Thompson in which a mirror 

 image is projected, and hence appears erect on the screen (fig. 97, 

 100). If a translucent screen is used with the object in a hori- 



