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mum when lamps having an efficiency of 3.1 watts per candle are used.
Thus the maximum efficiency of these
Lamps $1.00 each-Life 600 hrs. at 3 Watts per Candle.
Current costs 10 cts. per ㏋. per hour.
Fig. 4.
lamps under the conditions assumed is 3.1 watts per candle.
The lamps considered in the case shown in Fig. 4 cost $1.00; all other conditions
