Page:Incandescent electric lighting- A practical description of the Edison system.djvu/134

 and to have a life of 600 hours at 3 watts per candle. The current is assumed to cost 10 cents per h.p. hour.



The cost of the current is determined from the following formula:

Current cost=

w.p.c. × 16 × 100 × 1000 × cost of ct. per h. p. per hour 746