TABLE 187. 



INDEX OF REFRACTION. 



Index of Refraction of Metals and Metallic Oxides. 



* " Wied. Ann." voli 34, and " Phil Mag." (5) vol. 26. 

 t Wave-lengths A are in millionths of a centimetre. 



t Nearly pure oxide. 

 " Wied. Ann." vol. 39. 



SMITHSONIAN TABLES. 



181 



