216 



Mr. Powell on Li^ht and Heat. 



Small Photometer ; incandescent iron. 



•i.d^ 



See above (1.) 



Large photometer : glass case : two screens of plate-glass re- 

 placed after each experiment, the nearest close to, but not touching 

 the case ; the second at about one-quarter from first : incandescent 

 iron ball, four inches distant. 



After experiment, outer screen hot, inner very little so, case cool. 

 , ' Flame distant 1.5 inch. 



Sees. 





 30 



S'^'-e^" Expos'd 



in rasp J r 



25 



22 



25 



20 



After experiment 

 screen heated. 



See above (2.) 



