HEAT AND LIGHT FROM ELECTRIC CURRENTS 211 



221. Uses of electric heating devices. The electric smooth- 

 ing iron (fig. 103) is much more convenient for those whose 

 homes are provided with electricity than are the irons heated 

 by other methods. Furthermore, the electric iron when in 

 use is kept constantly at the desired temperature, so that 

 there is a saving of the time usually consumed in changing 

 or reheating the irons when coal or gas is used as the source 



FIG. 104. Use of electricity at different times of day 



The diagram represents a typical day's demands for electricity in New York City. 

 Redrawn from The Electrical Experimenter 



of heat. Because of these advantages, as well as the increased 

 cleanliness, electric irons are coming into common use in 

 commercial laundries and clothing establishments as well 

 as in private homes. Care must be taken not to allow the 

 current to flow while the iron is not in use. Fires may 

 be started in this manner. 



As a source of heat and light, electricity is more expensive 

 than gas, but there are compensations in the form of efficiency, 

 adaptability, and cleanliness. The number of kilowatts used 

 in New York City during a typical day and night is shown 



