Table 180. 



INDEX OF REFRACTION. 



Indices of Refraction of LUolds relatlTo to Air. 



189 



* Weegmann gives >*£,= '-S9668 — .000518/. Knops gives ^^= 1.61500 — .00056/. 

 t Weegmann gives fij>= 1. 51474 — .000665/. Knops gives /ii5= 1.51399 — .000644/. 

 t Wiillner gives /*(.= 1. 63407 — .00078/; fi^= 1.66908 — .00082 /; jt^ =: i. 69215— .00085/. 



§ Dufet gives ^^=1 1.33397— 10-' (125 / + 20.6/2 — .000435 /» — .00115/*) between 0° and 50°; and nearly the 

 same variation with temperature was found by Ruhlmann, namely, Mi)= 1.33373— io-'(20.i4/2 + .ooo494/*). 



Smithsonian Tables. 



