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HOW ELECTRICITY IS CONTROLLED 



TXIIC- A. 

 PORCELAIN 

 FUSE WIRE 



SCREW CONTACT 



PORCELAIN 



"POINT 



melt at a much lower temperature than others. Lead, 

 for example, melts very readily. If you have seen the 

 plumber solder pipes, you have noticed that he has a copper 

 instrument which is used to melt the solder, so you know 

 that red hot copper can melt solder. Such low melting 

 metals are used in making fuse wires. If a fuse wire is made 



a part of the elec- 

 trical circuit in a 

 house, it would evi- 

 dently melt if heated 

 to a point much 

 below that which 

 would melt the cop- 

 per wires carrying 

 electricity. Such a 

 c.Link wire placed in the 

 house circuit is 

 known as the fuse. If a short circuit is produced, the 

 fuse instantly melts, and thus the electricity is cut off from 

 the house, and danger from fire prevented. If we have 

 electric lights in our home, we should all know the loca- 

 tion of the fuse box, and we should understand how to 

 put in the fuse plugs in case they burn out. Of course, 

 we must take care first to turn back the switch, thus cutting 

 off all the electricity from the house, before we attempt to 

 do this. 



Measuring electricity. Each one of us should learn 

 to read the dials on the ordinary electric meter, which is 

 part of the equipment of every house that takes its elec- 

 tricity from the city supply. The meter is called the 

 wattmeter, and the readings are made in kilowatt hours. 

 For example, if we have ten lamps, each marked twenty- 



Fuses : A, Cartridge fuse ; B, Socket fuse ; 

 fuse. 



