2S4 E. L. Nichols — Age-coating in Incandescent Lamps. 



various periods, also the average absorbing power of their 

 coatings. 



Table III. 



Relative brightness, efficiency and transparency of lamp No. 2, at vari- 

 ous periods (each expressed in terms of its initial value taken as one 

 hundred). 



Relative Relative 



Time. brightness. efficiency. 



000- hours 100- 100- 100- 



100 " 78-1 81-5 91-44 



200 " 67-5 70-9 85-91 



400 " 60-4 66-8 82'46 



800 " 45-0 5T3 78-24 



Relative transparency 

 of bulb. 



Table IV. 



Relative brightness, efficiency and transparency of lamp 10, at various 

 periods {each expressed in terms of its initial value, taken as 100). 







Relative 



Relative 



Relative transparency 



Time* 



brightness. 



efficiency. 



of bulb. 







hours. 



100- 



100- 



100- 



50 





92-6 



92-6 





109 





91-4 



90-1 





200 





86-6 



87-3 



90-5 



400 





80-5 



81-6 





511 





78-7 



80-0 





600 





78-0 



79'5 





900 









85-0 





200h. 400h. 600h. 800h. 



90 

 80 

 70 



60 

 50 



*'~ - - — -^MSflfflENCTor coating 



90 

 80 

 70 



• — ;j~ - -^^RENCYorcoATING: 



T ° TA L BRIGHT*^ 



1 ..1 ,1:1, .1 1 



200 h 400 h 600h 800 h 



