KNOBLAUCH OX RADIANT HEAT. 



409 



Table XXXVIII {continued). 



the insertion when the heat of red-hot platinum is reflected by 



when the heat of an alcoholic fia me in Berzelius's lamp is reflected by the above bodies : 



1012 



9-00 



6-12 



20-25 



12-25 



9-87 



when the heat of the hot metallic cylinder is reflected by the same bodies : 

 887 



812 



650 

 22-50 



9-63 

 10-50 



8-87 

 8-00 

 6-62 



2237 

 9-63 



10-50 



tion, which was observed in the same manner in other reflecting 

 surfaces and diathermanous bodies. 



II. It still remained to be determined whether those surfaces 

 which exert a similar influence upon the rays of the Argand 

 lamp, i. e. which they reflect in such a manner that the heat re- 

 flected by the one is transmitted by the diathermanous media 

 used for testing in the same proportion as that reflected by the 

 others, would also reflect the heat from the other sources, so that 

 the rays reflected by them would pass through these substances 

 in the same manner. 



To ascertain this, I repeated the experiments performed with 

 the Argand lamp with the red-hot platinum, the flame of alcohol 

 and the cylinder at a dark red heat, using for reflexion those 

 surfaces the similar action of which upon the rays of heat of the 

 former appeared to me especially remarkable. 



The following table contains the numbers which were found 

 on the transmission of the heat of the Argand lamp reflected by 

 them through red glass, blue glass, alum, rock salt, calcareous 

 spar and gypsum : — 



Wlioii exposed to the r.ivs of tlie red-hot platinum, none of the snrfuces 

 by reflexion were capable of producing a greater deflection than 20°. 



