Table 1 97. 



INDEX OF REFRACTION. 

 Indices ol Rotiactlon ol Uqoldi relative to All. 



* Weegmann gives fiB= 1.59668 — .000518/. Knops gives fi^rr 1.61500— .00056/. 

 t Weegmann gives (i^ =1.5 1474 — .000665/. Knops gives Mb= i-5'399 — -oo°644/. 

 t \VullnergivesMc='-63407 — -o°o78'; >*/.= 1.66908 — .00082 /; ma = '-^gziS— -a»8s/. 



§ Dufet gives ^b= >-33397— '°"' ('*5' + 2°-^^~"^°°°-«35 ^ — -oo'iS^) between 0° and 50"; and nearly the 

 same variation with temperature was found by Ruhlmann, namely, ft^^: 1.33373— 10-' (20.14 ^ + -«»494'*). 



Smithsonian Tables. 



189 



