412 



KNOBLAUCH ON RADIANT HEAT. 



Tabl* XLI. 



On this occasion the needle of the thermo-multiplier became 

 placed at 4°'87 on the insertion of the red glass, when the direct 

 deflection of 13'^ was produced either by the unreflected heat of 

 the flame or by that reflected by silver or sheet iron ; and on 

 inserting the calcareous spar at 8°'63 to 8°"13, the heat of the 

 flame of alcohol being either unreflected or diffusely I'eflected by 

 the two metals just mentioned to produce a deflection of 20°. 

 After the reflexion from white oil-paint and black lac, in each 

 case a recess of the needle of the galvanometer from 13° to 7°*42 

 was observed when the red glass, and from 20° to 9°'5 when the 

 plate of calcareous spar was introduced between the reflecting 



Table XLII. 



A deflection of 3°'25 to 3°*5 is now constantly obtained as 

 often as the red glass is inserted, and of 9°'5 to 10° as often 

 as the calcareous spar is introduced, the direct deflection of 

 13°, and subsequently of 30°, being previously produced by 

 either the unreflected heat of the cylinder, or by reflexion from 

 any one of the surfaces under consideration. The same was 

 found to be the case with the other diathermanous bodies. The 

 bodies subjected to investigation, which exhibited the same de- 



