192 



Table 1 99. 



INDEX OF REFRACTION. 



Indices of Refraction of Liquids relative to Air. 



* Weegmann gives pi2>= 1-S9668 — .000518^. Knops gives ftji.= 1.61500 — .00056/. 

 t Weegmann gives fi^= 1. 51474 — .000665/. Knops gives /i^nr 1.51399 — .000644/. 

 t Wullner gives |i£.= 1.63407 — .00078/; jx^^i. 66908 — .00082/; /1a=^ 1-69215 — .00085/. 



§ Dufet gives /!*/)= 1.33397 — io-~' (125 / + 20.6/^ — .000435/' — .00115/*) between 0° and 50°; and nearly the 

 same variation with temperature was found by Ruhlmann, namely, ni^)::^ 1.33373 — 10""' (20. 14/2 -[-,000494/*), 



Smithsonian Tables. 



1 



