Table 185. 



INDEX OF REFRACTION FOR CLASS. 



The table gives the indices of refraction for the Fraunhofer lines indicated in the first column. The kind of glass, 

 the density, and, where known, the corresponding temperature of the glass are indicated at the top of the different 

 columns. When che temperature is not given, average atmospheric temperature may be assumed. 



(a) Fraunhofer's Determinations. (Ber. Munch. Akad. Bd. 5.) 



(b) Baillb's Determinations. (Quoted from the Ann. du Bur. des Long. 193, p. 620.) 



Flint glass. 



Density 

 Temp. C. 



B 

 C 

 D 

 bi 

 F 

 G 

 H 



2.98 



23'^.2 



1.5609 

 5624 

 5660 



5715 

 5748 

 5828 



5898 



3-22 

 1 8°. 4 



15659 



5675 

 5715 

 5776 



5813 



5902 



5979 



3.24 



22°.0 



1.5766 



5783 

 5822 



5887 

 5924 

 6018 

 6098 



3^44 



1.5966 

 5982 

 6027 

 6098 

 614I 

 6246 

 6338 



3-54 



23'5.2 



1 .604 5 

 .6062 

 .6109 

 .6183 

 .6225 



•6335 

 .6428 



3-63 



1-6131 

 .6149 

 .6198 

 •6275 

 •6321 

 •643s 

 -6534 



3^68 

 24°.o 



1.6237 

 .6255 

 •6304 

 •6384 

 .6429 

 .6549 

 .6647 



4.08 



12°.4 



1.677 1 



•6795 

 .6858 



•6959 

 .7019 

 .7171 

 •7306 



S-oo 



I.780I 



■7831 

 .7920 

 .8062 

 .8149 

 .8368 

 •8567 



Crown glass. (Bailie, ibid.) 



Density 

 Temp. C. 



2.49 

 23°^5 



B 

 C 

 D 

 bi 

 F 

 G 

 H 



5126 



5134 

 5160 

 5198 



C222 



5278 

 5323 



2.50 



17*^.8 



1.5244 



-5254 

 .5280 

 •5320 

 •5343 

 •5397 

 -5443 



2-5S 

 i8°.4 



1.5226 

 -5237 

 •5265 

 ■5307 

 •5332 

 -5392 

 ■5442 



(c) Hopkinson's Determinatio.vs. (Proc. Roy. Soc. vol. 26.) 



Density = 



A 

 B 

 C 



D 



E 

 bi 

 F 



(G) 

 G 

 h 

 Hi 



Hard 

 crown. 



2.486 



^■5II755 

 513625 

 514568 

 5'7ii4 



520331 



520967 



523139 

 527994 

 528353 

 530902 

 532792 



Soft 

 crown. 



2.550 



[.508956 

 .510916 

 .511904 



•514591 

 .518010 

 .518686 

 .520996 

 .526207 

 •526595 

 •529359 

 .531416 



Titani- 

 silicic 

 crown. 



2^553 



1-539155 

 •540255 



•543249 

 .547088 



•547852 



•550471 

 .556786 

 .556830 



•559999 

 .562392 



Flint glass. 



2.866 



[•534067 

 .536450 



•537673 

 .541011 



•545306 

 .546166 

 .549121 

 •555863 

 •556372 

 .560010 

 .562760 



3.206 



568558 

 57001 1 



574015 

 579223 

 580271 

 583S86 

 592190 

 592824 



597332 

 600727 



3^659 



61 5701 

 617484 

 622414 

 628895 

 630204 

 634748 

 645267 

 646068 

 651840 

 6562 1 9 



3^889 



639143 

 642874 



644866 



650388 



657653 

 659122 



664226 



6761 1 1 



677019 



683577 

 688569 



4.422 



1 .69653 1 

 701060 

 703478 

 7102OI 

 719II4 

 720924 

 727237 

 742063 

 743204 

 751464 

 757785 



N. B. — D is the more refrangible of the pair of sodium lines ; (G) is the hydrogen line near G. 



Smithsonian Tables. 



178 



