200 



KNOBLAUCH ON RADIANT HEAT. 



Table III. {continued). 



The distances of the heated cyhnder from the thermoscope 

 given in this table clearly show the great increase of the heat. 

 At the moment when the change in the transmission of the heat 

 observed in son.e diathermanous bodies occurred, its temperature 

 amounted to about 234"^ F. Even at its greatest heat no trace 

 of redness was visible even in the dark. 



3. The transmission of heat, radiating from one and the same 

 body at different stages of a red heat, still remained to be exa- 

 mined. For this purpose 1 heated a spiral of platinum wire to 



