USE OF ELECTRICITY IN THE HOME 387 



example, if one light uses 1 ampere of current at 110 volts, two lights 

 will use 2 amperes at 110 volts. The motor turns in the meter, 

 thus registering the amount of energy delivered to the consumer. 



Accuracy of Meters. As a rule watthour meters are quite 

 accurate. They need cleaning once in a while, as dirt and dust 

 usually tend to make them run slowly. Occasionally a meter may 

 be fast. 



Causes for Increase in Electrical Bills. There are a number of 

 causes for the increase in electric bills for any month. Some of the 

 causes are : 



1. Defective wire, which may allow the current to flow when 

 no lights or other electric instruments -are in use. This can be 

 determined by watching the small aluminum disc on the meter. 

 If it is revolving when all lights are out, there is probably a leak. 



2. An unusual number of cloudy days or much rainy weather 

 during any month may cause an extra consumption of current. 



3. Old lights which are dim do not give sufficient illumination, 

 and require an extra light to offset the decrease in light they cause 

 by their dimness. An old light is a very wasteful thing to use. 



Carbon lights are very expensive to operate as compared with 

 the Tungsten lamps. The latter may cost more to purchase, but 

 the amount of current that a carbon lamp consumes during its life- 

 time is about three times that consumed by the Tungsten lamp for 

 the same amount of light. One could not afford to use carbon 

 lamps if they were given to him, since it would be cheaper in the 

 end to buy good Tungsten lamps. 



Experiments. Measure the candle power of a Tungsten lamp and also of 

 a carbon lamp. How many watt hours will it take to run these lamps 400 

 hours (the average life of the lamp)? How much does it cost per candle power? 

 How much would it cost to run enough carbon lights to equal the candle power 

 of the Tungsten light? What is the difference in the cost? Subtract the price 

 of the Tungsten lamp from the difference in cost and thus determine the amount 

 of saving. 



4. Lights may sometimes be left burning for days in attics, 

 closets, and cellars, a practice which will increase the electric bill 

 for any month. 



5. An error may be made by the company's meter reader so that 



