Schrauf on the Optical Constants of Crystallized Substances. 483 



4. Chloride of Potassium and Cadmium. [2KCl+CdCl.] 



Rhombohedral. a : c=l : 1*6483. 

 o* B =l-58409 e B = 1*58420 



o- H = 1-62083 e H =l-62100 



5. Chloride of Ammonium and Cadmium. [2NH 4 Cl + CdCL] 



Rhombohedral. a 

 0)B = 1-59581 

 WH = 1-64142 



6. Nitrate of Soda. NaO, N0 5 . 



Rhombohedral. a : c= 1 : 1*1903. 

 o* B =l*57933 e«=l*33456 



c=l : 1*5/04. 

 e B = 1*59610 

 e H = 1*64180 



o* H = 1*62598 



e H =l-34395 



7. Nitrate of Potash. 

 1*49939 

 1*54045 



KO, NO.. 



/3 B = 1-49881 

 aH = 1-54045 /3 H = 1-53848 



Citric Acid. 3(C 4 H 2 4 , HO) +HO 

 a B = 1*50542 /3 B = 1-49432 



73=1-33277 

 y H = 1*34359 



7b = 1*48964 

 y H =l*50978 



9. 



a H =l*52541 /3 H = 1*51398 

 Sulphur. S. Prismatic, a : 6 : c= 1 : 0*5264 : 0*4279. 

 a B =2*22145 /3 B =2*02098 y B = 1*93651 



a H = 2*32967 /3 H =2*11721 y H =2*01704 



10. Quartz. 



11. Anatase. 



12. Apatite. 



Si0 2 [for control]. 

 0*3=1*54106 

 o* H = 1*55806 

 Ti0 2 . 



o*3=2*51118 

 o* H =2-64967 

 From Tumilla. 

 o» B = 1*63463 

 w = 1*65934 



e B = l*55012 

 e H = 1*56758 



en- 



2*47596 



e H =2*58062 



1*63053 



13. Beryl. From Elba. 



WB = 1*57028 



w H = 1-58884 



From Grao Mogor, Brazil, 

 a, =1-57762 



a, H = 1-60321 



From Nertschinsk. 



Wj3 =l-56630 

 w„= 1-58818 



2K2 



e H = 1*65260 



e B = 1-56540 

 e_=l-58261 



€ B =1'57148 

 e H =l*59542 



e B =l*56l65 

 e H = 1-58393 



