TABLE 197. 



INDEX OF REFRACTION. 



Indices of Refraction of Liquids relative to Air. 



* Weegmann gives jti fl =: 1.59668 .000518*. Knops gives /K F = 1.61500 .00056*. 

 t Weegmann gives f* c = 1.51474 .000665*. Knops gives H D = 1.51399 .000644*. 

 t Wiillner gives fi^= 1.63407 .00078*; i*-p= 1.66908 .00082*; ^ = 1.69215 .00085*. 



Dufet gives /./>= '-33397 io 7 (125 * + 20.6** .000435/3 .oonj* 4 ) between o and 50; and nearly the 

 same variation with temperature was found by Ruhlmann, namely, MB !-33373 '~ 7 (20. 14 * 2 +. 000494 *). 



SMITHSONIAN TABLES. 



189 



