. A-B-C of electricity. A-B-C OF ELECTRICITY Now, if you will read patiently and care-fully, we will try and explain how both theselights are have seen that the telegraph, tele-phone, electric bells,etc., are worked bybatteries. Electriclights, however, re-quire such a largeamount of current thatit is too expensive toproduce them in largequantities by small number oflamps could be lightedby batteries, but if wewere to attempt to usethem to light 500 or1,000 lamps together,the expense would beso enormous as tomake it entirely out ofthe question. There are many mill-i
. A-B-C of electricity. A-B-C OF ELECTRICITY Now, if you will read patiently and care-fully, we will try and explain how both theselights are have seen that the telegraph, tele-phone, electric bells,etc., are worked bybatteries. Electriclights, however, re-quire such a largeamount of current thatit is too expensive toproduce them in largequantities by small number oflamps could be lightedby batteries, but if wewere to attempt to usethem to light 500 or1,000 lamps together,the expense would beso enormous as tomake it entirely out ofthe question. There are many mill-ions of incandescentlamps in use in the United States, but youwill easily see that there could not be thatnumber used if we had to depend on batteries to light them. You will understand this56. Fig. 16 ELECTRIC LIGHT more thoroughly when you have finishedreading this little book. Well, you will ask, if we cannot use bat-teries, what is used to produce these electriclights? Machines called dynamo-electric ma-chines, or generators, which are driven bysteam-engines or water-power, are used toproduce the electricity which makes theselamps give us light. You will remember that in the chapteron Magnetism we ex-plained to you howelectricity makes mag-netism, and now wewill explain how, in thedynamo, magnetismmakes electricity. It has been foundthat the influence of amagnet is very strongat its poles, and thatthis influence is alwaysin the same lines. Thisinfluence has been de-scribed as lines offorce, which you willsee represented in the sketch above by the dotted lines (Fig. 17). Of course, these lines57
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectelectri, bookyear1915
