ILLUMINATION AND 



445 



experience in the art of illumination. A few fundamental 

 principles, however, underly the general problem and these will 

 be treated briefly. 



Interior illuminants are confined practically to the vacuum 

 Mazda lamp and the gas-filled lamp, although carbon lamps are 

 unfortunately still used in some instances. The purposes to be 

 accomplished by interior illumination are to provide sufficient 

 light for working, reading, writing, etc., and to distribute this 

 light properly without glare. A lamp with a clear globe may give 



Fio. 401. Single lamp in room. 



sufficient light r\nd distribute it properly, but the glare of the bare 

 filament may be objectionable. Further, the artistic 

 illumination should be kept in mind. The fixtures should be 

 log, the propel- liuht thrown on pictures, decoration- 



iiii'j and writing require an illumination of from \\ to 4 

 foot -candles, whereas drafting and detail work may reqiii 

 many as 8 foot -cam lies. Thi> is I he illumination necessary on a 

 about -^ in. above tin- Moor. In an office, or dral'i 

 le>irable that thi- light be provided entirely by o\ , 

 source-. Wh requires a higher info -f illu- 



mination than the PBS( of the room. d-<k lamp- may lie provided. 

 When lighting an it. 1 --iling light in the renter 



^ufliee if the : rge. In this car 



