182 PROJECTION OF IMAGES OF OPAQUE OBJECTS [Cn. VII 



FIG. 98. THE NEW REFLECTING LANTERN OF WILLIAMS BROWN & EARLE 

 (No. 3 BR 15). 



(Cut loaned by Williams Brown & Earle). 



This is a combination projector for lantern slides and for opaque objects. 



Commencing at the right: 



N Arc lamp in the lamp-house with the feeding screws extending beyond 

 the lamp-house. 



M Lamp-house of metal with the ventilator at the top. 



C First element of the condenser for giving approximately parallel rays. 



D The opaque object in position. The light from the lamp shines directly 

 upon it and is reflected outward toward the projection objective (). 



E Projection objective for opaque objects. 



F Mirror for reflecting the image of the opaque object to the screen and for 

 correcting the right to left inversion. 



B Water-cell and second element of the condenser for transparency pro- 

 jection. 



A Opening for the lantern-slide carrier. 



L Projection objective for lantern slides. 



For lantern-slide projection a mirror at C is brought into position to reflect 

 the light out along the optic axis of B and L. 



objective must be used for such a screen distance. (For a magnifi- 

 cation of six and a 15 meter screen distance, an objective of 250 cm. 

 (100 inches) is necessary). 



289. Arc lamp and amount of current. If one wishes to use 



more than 25 amperes, the arc lamp should be hand-feed. Up to 

 25 amperes, the right-angled carbons work well. Beyond that 

 amount the inclined or vertical carbons are more satisfactory for 



