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 the temperature is not given, average atmospheric temperature may be assumed. 



(a) FRAUNHOFER'S DETERMINATIONS. (Ber. Munch. Akad. Bd. 5.) 



Density 

 Temp. C. 



li 



C 

 D 







F 

 G 

 If 



Flint glass. 



18^.75 



1.62775 

 .62965 



.64202 

 .64826 

 .66029 

 .67106 



1.60204 

 .60380 

 .60849 



61453 

 .62004 

 .63077 

 .64037 



Crown glass. 



2.756 



1-55477 

 55593 

 55908 



.56674 

 57354 

 57947 



2-535 

 '7-5 



I-52583 

 .52685 



52959 



533! 

 53605 

 .54166 



54657 



52530 

 .52798 



53*37 

 53434 

 53991 

 .54468 



(b) BAILLE'S DETERMINATIONS. (Quoted from the Ann. du Bur. des Long. 193, p. 620.) 



Flint glass. 



Density 

 Temp. C. 



B 

 C 



1) 

 b, 

 K 

 G 

 H 



1.5609 

 .5624 

 .5660 



5715 

 5748 

 .5828 

 .5898 



I-5659 



5675 

 57 '5 

 5776 



5902 

 5979 



3-24 



22.0 



1.5766 



5783 

 .5822 



5887 

 5924 

 .60l8 



1.5966 

 .5982 

 .6O27 

 .6098 



.6246 

 .6 33 8 



3-54 

 23. 2 



1.6045 

 .6062 

 .6109 

 .6183 

 .6225 



6335 

 .6428 



3-63 

 i3-7 



1.6131 

 .6149 

 .6198 

 .6275 

 .6321 



6435 

 6534 



3-68 

 2 4 .o 



1.6237 



6255 

 .6304 

 .6384 

 .6429 



6549 

 .6647 



4.08 

 1 2. 4 



1.6771 



6795 

 .6858 



6959 

 .7019 

 .7171 

 .7306 



5.00 



22. S 



I.78OI 



7831 

 .7920 

 .8062 

 .8149 



.8567 



Crown glass. (Bailie, itiit.) 



Density 

 Temp. C. 



I 



C 



1) 

 in 

 F 

 G 



H 



1.5126 



5'34 

 .5160 

 .5198 

 .5222 

 .5278 

 5323 



2.50 

 17^.8 



I-5244 

 5254 

 .5280 

 5320 

 5343 

 5397 

 5443 



1.5226 

 5237 

 5265 

 5307 

 5332 

 5392 

 5442 



2.80 



1-5157 

 .5166 



5192 

 5234 

 5256 

 5313 

 .5360 



1-5554 

 .5568 

 .5604 

 5658 

 .5690 



5769 

 5836 



(c) HOPKINSON'S DETERMINATIONS. (Proc. Roy. Soc. vol. 26.) 



Density = 



Hard 

 crown. 



2.486 



Soft 

 crown. 



Titani- 

 silicic 

 crown. 



Flint glass. 



2.866 



3.206 



3-659 



3.889 



A 

 B 

 C 

 D 

 E 

 b! 

 F 



(G) 

 G 

 h 



.5145 



520331 

 .520967 



523139 

 .527994 



528353 

 .530902 



532792 



1.508956 

 .510916 

 .511904 

 .514591 

 .518010 

 .518686 

 .520996 

 .526207 

 526595 

 529359 



I-539I55 

 540255 



543249 

 .547088 

 .547852 

 55 47i 

 556386 

 556830 

 559999 

 562392 



1.534067 

 536450 

 537673 

 .54101 i 



545306 

 .546166 

 .549121 

 555863 

 55 6 372 

 .560010 

 .562760 



1.568558 

 .570011 

 574015 

 579223! 

 .580271 I 

 .583886) 

 .592190 

 .592824 



597332 

 .600727 



1.615701 

 .617484 

 .622414 

 .628895 

 .630204 

 .634748 

 .645267 

 .646068 

 .651840 

 .656219 



1-639143 

 .642874 

 .644866 

 .650388 



657653 

 .659122 

 .664226 

 .676111 

 .677019 



683577 

 .688569 



1.696531 

 .701060 

 .703478 

 .710201 

 .719114 

 .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. 



I 7 8 



