TABLE 199. 



INDEX OF REFRACTION. 



Indices of Refraction of Liquids relative to Air. 



* Weegmann gives H D = 1.59668 .000518 1. Knops gives ft F = 1.61500 .00056 1. 

 t Weegmann gives /x^zz 1.5 1474 .000665*. Knops gives M/> !'5i399 .000644*. 

 % Wiillner gives /IA C = 1.63407 .00078^; ft^= 1.66908 .00082*; /i A = 1.69215 .00085^. 



Dufet gives ftp 1.33397 io~ 7 (i2S ^ + 20.6^ .000435 ^ .oons^ 4 ) between o and 50; and nearly the 

 same variation with temperature was found by Ruhlmann, namely, M.D 1-33373 io~ 7 (20. 14 ^ + .000494 /*). 



SMITHSONIAN TABLES. 



