CH. VII] PROJECTION OF IMAGES OF OPAQUE OBJECTS 173 



of given focus, the greater will be the brightness. With the same 

 objective, the greater the distance of the objective from the screen, 

 the less will be the brightness 



FIG. 92. CHADBURN'S OPAQUE 



LANTERN WITH ONE SOURCE 



OF LIGHT. 



(From Chadwick, Hepworth and 

 Wright). 



L Source of light shining directly 

 upon the opaque object. 



M Beam of light from the opaque 

 object to the objective and to the 

 screen. 



FIG. 93. CHADBURN'S OPAQUE LAN- 

 TERN WITH Two SOURCES OF LIGHT, i 

 (From Chadwick, Hepworth and Wright). 



This form requires two sources of 

 light and two condensers. The light 

 is projected directly upon the object 

 and from the object it extends out 

 through the objective to the screen. 

 This method is still often employed. 



The same lantern, connected in the 

 usual way, was employed for trans- 

 parency projection (fig. i). 

 L-L Source of light and condenser arranged to send the light directly to 

 the opaque object. 



D-D Hinged door for the support of the book, picture or other object. 

 When the door is closed, the light from both sources shines directly upon the 

 opaque object. 



B Beam of light from the object to the objective. 



A Objective of large aperture for projecting the image of the opaque object 

 upon the screen. 



