NATURAL AND ARTIFICIAL LIGHTING 



67 



illuminated with an intensity of about 3 to 5 foot-candles; 

 it is of no benefit to the reader, however, to have the walls and 

 ceiling of the room illuminated to the same extent. In fact, 

 if all other objects in the room were illuminated to the same 

 intensity as the book, they would tend to draw the attention 

 of the reader from the page. We all know that the attention 



FIG. 56. Upright gas 

 mantle lamp. 



FIG. 57. The distribution 

 curve for the lamp. 



FIG. 58. A reflex or inverted gas mantle 

 lamp with prismatic glass reflector. 



FIG. 59. The distribution 

 curve for the lamp. 



of the audience in a theater is directed to the players by 

 subduing: the light in the body of the house and increasing the 

 light on the stage. 



In modern lighting, the choice of fixtures and shades is 

 determined by the use to be made of the light. If the purpose 

 is to supply light for the general illumination of the room, the 



