ELECTRICAL INVENTIONS 



249 



As far as the principle of operation is concerned, such devices 

 can be readily understood from the diagrams of Figure no. 



FIG. no. (a) An electric heater; (6) an electric percolator sectioned to show 

 inside; (c) an electric flatiron, showing diagram of inside; (d) an electric toaster. 



In the toaster, for instance, the current going through the 

 wires on the frame causes them to become red hot. The slice 

 of bread on the rack is exposed to their heat and so is toasted. 



