554 



TABLE 585.— REFLECTION AND TRANSMISSION OF VARIOUS MATERIALS 

 FOR VERY LONG WAVELENGTHS 



With quartz, 1.7 cm thick: 60 to 80/i, absorption very great; 63/ti, 99 percent; 82/jl, 97.5; 

 97m, 83. 



Wavelength 



X=82 M * 



X = 108/tt 47.1 



Iceland 

 spar Marble 



43.8 



Percentage reflection 



Rock 

 salt 



25.8 

 20.3 



Sylvite 



36.0 

 19.3 



KBr 

 82.6 



31.1 



KI 



29.6 

 35.5 



Fluo- 



rite Glass 



19.7 — 

 20.2 19.2 



Water Alcohol 



9.6 — 

 11.6 1.6 



Percentage transparency 

 Uncorrected for reflections 



Solid Thickness 



Paraffin 3.03 



Mica 055 



Hard rubber 40 



Quartz || axis 2.00 



Quartz, amorph 3.85 



Rock salt 21 



Fluorite 59 



Diamond 1.26 



Quartz i axis 2.00 



" " " 4.03 



" " " 7.26 



11.74 



14.66 



Trans- 

 parency 



57.0 

 16.6 

 39.0 

 62.6 





 21.5 



5.3 

 45.3 

 81.3 

 66.4 

 49.8 

 35.5 

 29.0 



* Restrahlung from KBr. t Isolated with quartz lens. 



TABLE 586.— TRANSPARENCY OF BLACK ABSORBERS 

 (percent) 



TABLE 587.— RELATIVE REFLECTIVITY OF SNOW, SAND, AND OTHER 



MATERIALS 173 



"> Hulburt, Journ. Opt. Soc. Amer., vol. 17. p. 23, 1928. 

 * Yellow-white grains of many kinds. t Very white. 



t Anhydrous. § Handkerchief. 



SMITHSONIAN PHYSICAL TABLES 



