E. L. Nichols — Age-coaiing in Incandescent Lamps. 281 



Conditions after 4-00 hours. 

 Volts. Amperes. Ohms. Candle-power. Watts per candle. 



101-8 0-428 237-7 9'67 4-510 



Light transmitted by the coating after 400 hours. 



X = -750 

 •713 

 •635 

 •580 

 •538 



79*3 per cent 

 80-9 



82-3 

 82-0 

 82-6 



X = -507 

 •481 

 •460 

 •443 

 •429 



83-5 per 



83-6 



84-0 



84-3 



82-1 



cent 



Conditions after 800 hours. 

 Volts. Amperes. Ohms. Candle-power. Watts per candle. 



101-9 0-415 245-6 7*20 5-880 



Light transmitted by the coating after 800 hours. 



X= -750 

 •713 

 •635 

 •5S0 

 •538 



75*7 per cent 

 75-9 



78-0 

 78'6 

 78'4 



X = -507 

 •481 

 •460 

 •443 

 •429 



78 *7 per cent 



79-4 



79-9 



80-5 



77-3 



Another typical case was that of lamp No. 10, which, was a 

 lamp with a treated filament. It was maintained at a very 

 different degree of incandescence, being a lamp of low effi- 

 ciency, which when set at the voltage indicated by the manu- 

 facturer, required an expenditure of 5 -16 watts per candle. 

 The age-coating of this lamp approached even more nearly to 

 complete neutrality of shade than did most of those which we 

 had occasion to measure. The results obtained at two hundred 

 and nine hundred hours are given in Table II. 



Table II. 



Lamp No. 10 (treated filament). 



Initial Conditions. 



Volts. 



Amperes. Ohms. Candle-power. Watts per candle. 



36-0 



1-171 30-63 8-2 5-16 





Conditions after 200 hours. 



Volts. 



Amperes. Ohms. Candle-power. Watts per candle. 



35-9 



1-145 31-27 7-1 5-91 



Light transmitted by the coating after 200 hours. 



X = -750 



91-9 per cent X — -507 90'7 per cent 



•713 



90 : 4 -481 90-4 



•635 



89-5 -460 90-7 



•580 



90-5 -443 90-5 



•538 



90-5 -429 90-4 



