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minimum total cost is $654, and the maximum efficiency of the lamp is 2.62 watts per candle. In this case. Fig. 8, the current costs half as much as in the previous case, other conditions being the
Lamps 50 cts. each—Life 1200 hrs. at 3 Watts per Candle.
Current costs 5 cts. per ㏋. per hour.
Fig. 8.
same. The minimum total cost is reduced from $654 to $362. The maximum efficiency in this case is 2.88 watts per candle. In Fig. 9 the current costs twice as much as in the previous case and the
