LIGHTING THE HOME 41 



connected with the tanks. Acetylene gas gives a very 

 brilliant white light. Occasionally one hears of dangerous 

 explosions from the use of these outfits. 



Button 



LABORATORY EXERCISE 6 



Purpose. To generate acetylene. 



Apparatus. Test tube, calcium carbide. 



Directions. Fill a test tube half full of water and place it 

 on a test tube rack. Drop into the tube two or three small 

 pieces of calcium carbide. Notice what happens in the water. 

 Stand a little distance from the tube and apply a lighted match 

 to the mouth. Note the appearance of the flame due to the 

 burning of the acetylene. 



Electricity. The latest advance made in lighting is the 

 use of electricity, which is more convenient even than gas. 

 When the current first enters the house 

 it passes through a meter, which records 

 the amount of electricity that is used in 

 the house. This meter has several dials 

 and looks much like a gas meter. A 

 switch is usually provided so that the cur- 

 rent may be disconnected. If an extra 

 strong current should pass through the 

 wires, they would become heated and 

 might set fire to the house. To avoid this 

 danger, a fuse box is provided where the 

 current enters the house. The fuses are 

 made of such materials that if too strong a current passes 

 through them they melt. Thus the circuit is broken and the 

 current does not pass through the wires in the house. In 

 wiring the house, care should be taken to see that the wires 

 are properly covered with some insulator, which, being a non- 

 conductor of electricity, will not permit the current to pass 

 through. 



-Screw 



Glass tube 



'//amertt 



FIG. ii. Incandescent 

 lamp. 



