523 



TABLE 543.— INDEX OF REFRACTION OF SELECTED MONOREFRINGENT 

 OR ISOTROPIC MINERALS (concluded) 



Index of 

 refraction 

 Mineral Formula X = 0.589<i 



Eglestonite HgO-2HgCl 2.490* 



Hauerite MnS, 2.690* 



Alabandite MnS 2.700* 



Cuprite Cu 2 2.849 



* Li line. 



TABLE 544.— INDEX OF REFRACTION OF MISCELLANEOUS MONOREFRINGENT 



OR ISOTROPIC SOLIDS 



Spectrum Index of 



Substance line refraction 



Gelatin, Nelson no. 1 D 1.530 



various D 1.516-1.534 



Gum Arabic red 1.480 



" red 1.514 



Obsidian D 1.482-1.496 



Phosphorus D 2.1442 



Pitch red 1.531 



Potassium bromide D 1.5593 



chlorstannate. D 1.6574 



iodide D 1.6666 



Resins : Aloes red 1.619 



Canada balsam . red 1.528 



Colophony red 1.548 



Copal red 1.528 



Mastic red 1.535 



Peru balsam ... D 1.593 



Selenium A 2.61 



B 2.68 



C 2.73 



" D 2.93 



Sodium chlorate D 1.5150 



Strontium nitrate D 1.5667 



TABLE 545.— INDEX OF REFRACTION OF MISCELLANEOUS UNIAXIAL CRYSTALS 



Crystal 



Ammonium arseniate NH«H 2 AsC>4 . 



Benzil (C,H 6 CO) 2 



Corundum, A1 2 3 , sapphire, ruby... 

 Ice at — 8°C 



Ivory 



Potassium arseniate KH 2 AsO« 



ii ii ii 



Sodium arseniate Na 3 AsGvl2H 2 0. 



" nitrate NaNOa 



phosphate Na 3 PGvl2H 2 . 

 Nickel sulfate NiSGv6H 2 



Strychnine sulfate 



SMITHSONIAN PHYSICAL TABLES 



