54 THE PRODUCTION AND USE OF LIGHT 



easily bent and are placed in the walls and ceilings of the build- 

 ing when it is being constructed. When it is necessary to 

 turn a corner with a conduit, as in passing from the wall of a 

 room into the ceiling, care is taken to make the turn a curve 

 instead of a sharp angle. When the building is nearly com- 

 pleted a long, flexible steel, resembling somewhat a long, 

 straight clock spring, called a " fishing wire," is pushed through 

 the conduit; the insulated copper wire is attached to the end 

 of the fishing wire and pulled into place in the conduit. The 

 placing of electric wires in conduits, not only safeguards the 

 building against fire, but also makes it possible to remove, 

 to repair, or to replace the wiring of the building without injury 

 to the walls or the decorations. 



In wiring an old building in which no conduits were placed 

 when the building was constructed, the wires are " fished" 

 through the walls and ceilings, the electricians working 

 through small openings made in the walls, floors, or ceilings. 

 Flexible insulating tubing called LOOM is slipped over the wire 

 till it is completely encased before the wire is drawn into place. 



XII. NATURAL AND ARTIFICIAL LIGHTING 



69. Importance of Studying the Lighting Question. 



Thinking people are rapidly coming to recognize the fact that 

 more attention must be given to the lighting of our houses, our 

 stores, our factories, and especially our libraries and school- 

 rooms. All who have given this matter special attention agree 

 that too careful consideration can not be given this lighting 

 problem in this day when we spend so large a portion of our 

 lives in reading and studying or in other occupations requiring 

 close and almost constant use of the eye. Factory superin- 

 tendents and school officials are especially active in endeavor- 

 ing to secure better light for employees and students. Factory 

 superintendents find that it pays financially to provide the best 

 lighting conditions possible for their employees. School 

 officials and parents should give careful attention to securing 

 the best of light in the school and the home. 



