On the Influence of Color on Radiation. 



25 





Cylinder No. 3. 



Nature of coatins. 







Date 



£ • 



.2 bi 





o 



Sec.'g 



Carbonate of niagne- Yellow- ? 



sia. .ish white > 



Carb. of lime, (chalk) White. 



Carb. of lead. 





Prussian blue. 

 Litmus. 



Bichromate potassa 



Alkanet. 



Do. rendered blue 

 by potassa 

 India ink. 



1 do. 



Carb. of lead in oil of 



lavender. 

 Do. blackened by 



hydro sulphate of 



White. 



Blue. 



Blue. * 



Reddish 

 brown. 

 Crimson. 



Blue. 



Black. 



potass 



White 



Black. 



879 

 877 



25 805 

 3) 831 



Nov. 1 854 



11926.7 



17 



18 



21 



938.2 



776 



836 



c a 





a o « 



3 



- hi 



to 



5 o 



Remarks 



850 



See's See's 



Oct. 11 859.5 !862 



937 



969 



894.5 

 950 



819 

 869 



843.5 862 



I 





1011 



Rough, in specks 

 projecting. 

 1034! do. 



103^ $ Smooth and some- 

 ( what shining. 



871 Rough. 



870 Not uniform. 



{ Streaked and not 

 \ smooth. 



989 Uniform. 



986 



1001 



959 Not smooth. 



More uniform, 



(mean 697) 

 Uniform, but not 

 glossy on surface. 



976 



992 



1000 



etrated the coating. 



The effect of changing the crimson of alkanet to a blue was ap- 

 parently to decrease its radiating power about one per cent, or the 

 change of color in reality did not alter the power. The carbonate 

 of lead lost also slightly, or rather was not affected, by the change 

 not only of its surface, but of a considerable part of its mass, for the 

 oil of lavender having evaporated, the hydro sulphate of potassa pen- 



The substance by means of which the coating 

 was applied, seems not to have sensibly affected the radiating power; 

 the carbonate of lead applied with gum differing in radiating power 

 but four per cent, from that applied with oil of lavender. 



The colors rank from the foregoing table, blue, two varieties ; 

 black, brown, crimson, white, black, blue, white, three varieties. 

 There is no certainty that the litmus and alkanet, changed to blue 

 by potassa, were originally the same in color. The surfaces were 

 very different in regard to uniformity and smoothness ; the alkanet 

 was perfectly uniform, but not at all glistening ; it may be described 



In this table, we have the greater 

 number of whites at the bottom of the scale of radiation, and of blue 

 and black at the top ; but this is all that can be said, for a white, a 

 black, a blue, are in close proximity near the middle of the scale. 



Vol XXX— No. 1. 4 



as of a uniform minute roughness. 



