352 HOW ELECTRICITY IS MADE OAT A LARGE SCALE 



ampere,, having a voltage of one volt, will furnish in the 

 course of one hour one watt hour of energy. Energy for 

 electric lighting is sold at the rate of about ten cents per 

 kilowatt hour. For other purposes it is less expensive. The 

 meters commonly used measure the amperes, volts, and time 

 automatically, and register the electric power supplied in 

 watt hours. 



