4-4-2 Mr. B. Powdirs experimental Inquiri/ into the Nature 

 Incandescent iron. No Screen. 



(14.) Flame of an Argand lamp without its chimney. 

 Distance 3 inches. 



Glass Screen 1 "5 inch from bulbs. 



u 



Temperature of Screen 

 before Experiment. 



17 



Rise of Thermometers 

 in 1 min. centigrade. 



A. white. B. black 



1-25 

 1-25 

 1-75 

 1-25 

 1- 



2-25 

 2-25 

 2-25 

 2-75 

 2-25 



Temperature 



of Screen 

 after Experi- 

 ment. 



23 



Mean 



1-3 



2-35 



Effect of the Screen alone, heated above 25". 



•25 



•25 



The former result dimi- 1^ 

 nished from this effect J 



1-05 



2^10 



(15.) In 



