KNOBLAUCH ON HADIANT HEAT. 



229 



Table XVII. [continued). 



Hence no doubt remains in my mind that differences would 

 also have been evident in the previous experiments had any 

 eocisted. 



If, instead of the Argand lamp, a metallic cylinder below 

 234° F. be used, all these differences should again disappear ; 

 for the rays from the substances placed before it, as also the heat 

 emitted by the cylinder itself, pass through the diathei'manous 

 bodies in the same manner (see Table XV.) ; and it must there- 

 fore be a matter of indifference as regards the radiation, in what 

 proportion they are mixed together, according as they issue at 

 one or the other plate. 



The following numbers (the ai'ithmetic means of two observa- 

 tions) confirm this : — 



Table XVIII. 



