14. October 1861. 



921 



Hauptindices zweiaxiger Krystalle (Rudberg). 

 Arragonit (negativ). 



a. n : |/ 2 = 1,6672 n = 2,357S A = 0,06344. 



N 



1,6806 



1,6820 



1,6859 



1,6908 



1,6952 



1,7032 



1,7101 



n 





1,6820 



1,6857 



1,6906 



1,6950 





1,7105 



N-n 









+ 2 



+ 2 



+ 2 





— 4 



ß. n :|/ 2 =r 1,6632 n =2,3521 A o =0,062S4. 



N 



1,6763 



1,6778 



1,6816 



1,6863 



1,6905 



1,6984 



1,7051 



n 





1,6776 



1,6814 



1,6860 



1,6903 





1,7055 



N-n 





■+- 2 



-4- 2 



+ 3 



-+- 2 





- 4 



]/ 2 =1,5207 n =2,1506 A =0,04315. 



N 



1,5275 



1,5282 



1,5301 



1,5326 



1,5348 



1,5388 



1,5423 



n 





1,5282 



1,5301 



1,5325 



1,5347 





1,5424 



N-n 













•+- 1 



+ ' 





- 1 



Topas (positiv). 



«. n o :y 2 =l,609& « =2,2766 >.„ =0,05053. 



N 



1,6179 



1,6188 



1,6211 



1,6241 



1,6265 



1,6312 



1,6351 



n 





1,6187 



1,6209 



1,6238 



1,6264 





1,6354 



N-n 





+ 1 



-*- 2 



-+- 3 



+ 1 





- 3 





ß. 



n :\/ 2 



= 1,6025 



«0=^2662 A = 



0,05040. 





N 



1,6105 



1,6114 



1,6137 



1,6167 



1,6191 



1,6237 



1,62" 



n 





1,6113 



1,6135 



1,6163 



1,6189 





1,62" 



N-n 





+ 1 



-*- 2 



H- 4 



-1- 2 





- 



n Q -.y 2 = 1,6004 n =2,2633. A =0,05039. 



N 



1,6084 



1,6094 



1,6116 



1,6145 



1,6170 



1,6215 



1,6254 



n 





1,6092 



1,6114 



1,6143 



1,6168 





1,6257 



N-n 





-+■ 2 



+ 2 



-H 2 



H- 2 





— 3 



