REPORT ON RADIANT HEAT. 19 
The results of different sets of experiments are given in the 
tabular form, and apply to coatings of a great variety of sub- 
stances differing in their chemical nature, as well as in rough- 
ness, texture and colour. The following table is extracted as 
fully exhibiting the general result of all the experiments; the 
substances being arranged in the order of their radiating powers, 
beginning with the highest. 
Nature of Coating. Colour. Surface. 
Litmus blue. Blue. 
Prussian blue. Blue. Rough. 
Ammon. sulphate Greenish blue Rough 
of copper. : SM 
Peroxide of manga- Brothiat black. ie ot shining, but 
nese. uniform, 
India ink. Black. Not smooth. 
‘ @Streaked: 
Bichromate of potash. Brown. si thn chteales 
India ink. Black. Smooth. 
Alkanet. Crimson. Not shining, bu 
uniform. 
Carb. of lead in oil White. Smooth, not 
of lavender. shining. 
Sulphuret of lead. Black. 
Alkanet blue. Blue. 
Carb. magnesia. White. Rough. 
Carb. lead in gum. White. Smooth. 
Carb. of lime. Dingy white. Medium. 
Vermilion. Red. Smooth. 
Sulph. baryta. White bluish. Rough. 
Golden sulphuret of B Smooth, in 
é rown. 
antimony. streaks. 
Indigo. Blue. Smooth. 
-Cochineal. Crimson. Smooth. 
Red lead. Orange. Smooth. 
Sulph. baryta. White. _Medium. 
‘ Plumbago. Black. Bre ven tp 
; but uniform. 
-Chrom. lead. Yellow. Smooth, 
‘ . Smooth, in 
Gamboge. Olive green. ays Se 
_Bisulphuret of tin. Yellow. Smooth. 
c2- 
