224 



KNOBLAUCH ON RADIANT HEAT. 



Table XIV. 



If we connect with this the result obtained above (p. 196 to 

 202), according to which the proportion of the heat permeating 

 diathermanous media is constant whatever the temperature of 

 the radiating body may be (between 88° and 234° F.), it is evi- 

 dent that the heat which, within this range of temperature, is 

 emitted bij the most different adiathermanous substances, the 

 structure of the surface of which is not uniform, when heated by 

 conduction jJermeates in the same manner the diathermanous sub- 

 stances used to test them. 



2. The next question was, how the heat radiated by the bodies 

 would react as regards its transmission through diathermanous 

 media, when heated, not by conduction, as in the first series 

 of observations, but by the radiation of heat from different 

 sources. 



To ascertain this, I first exposed the substances used to radiate 



Jl 



