3 oo 



TABLES 363-365. 



REFLECTING POWER. 



TABLE 363. Reflecting Power of Powders (White Light). 



Various pure chemicals, very finely powdered and surface formed by pressing down with glass plate. White (noon 

 light) light. Reflection in per cent. Nutting, Jones, Elliott, Tr. 111. Eng. Soc. 9, 593, 1914. 



Aluminum oxide 83 . 6 



Barium sulphate 81 . i 



Borax . . 



Magnesium carbonate 86 . 6 



(block) 88.0 



Sodium chloride 78.1 



Sodium sulphate 77. 



Starch. . 



Borax 81.6 Magnesium oxide 85.7 Starch 80.3 



Boric acid 83.2 Rochelle salt 79-3 Sugar 87.8 



Calcium carbonate 83 . 8 Salicylic acid 81.1 Tartaric acid 79 . i 



Citric acid 81.5 Sodium carbonate 81 



TABLE 364. Variation of Reflecting Power of Surfaces with Angle. 



Illumination at normal incidence, i J watt tungsten lamp, reflection at angles indicated with normal. 111. Eng. Soc., 

 Glare Committee, Tr. 111. Eng. Soc. n, p. 92, 1916. 



TABLE 365. Infra-red Reflectivity of Tungsten (Temperature Variation). 



Three tungsten mirrors were used, a polished Coolidge X-ray target and two polished flattened wires mounted 

 in evacuated soft-glass bulbs with terminals for heating electrically. Weniger and Pfund, J. Franklin Inst. 



See also Weniger and Pfund, Phys. Rev. 15, p. 427, igig. 



SMITHSONIAN TABLES. 



