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ELEMENTS OF ELECTRICAL ENGINEERING. 



middle main is to tend to increase the voltage which acts on one 

 set of lamps and to decrease the voltage which acts on the other 

 set of lamps. These voltage relations are clearly represented for 

 a particular case in Fig. 157. This figure shows the state of 



100 amperes 



(jA-s*t 



10 amperes 



90 amperes 





Fig. 157. 



affairs when the A-set of lamps takes 100 amperes, and the ^-set 

 90 amperes, each main having J^-ohm resistance, and the lamps 

 being supposed to be bunched at the ends of the mains for the 

 sake of simplicity. Electric current may always be considered 



100 amperes 



90 amperes 



= 5 volts. r = jvolt. e 4% volts. 

 Fig. 1573. 



as flowing down hill so that the electric level (or potential) is to 

 be thought of as falling off along each main in the direction of 

 the current, as indicated by the fine inclined lines in Fig. 



