10 



BULLETIN 1108, U. S. DEPARTMENT OF AGRICULTURE. 



TABLES. 



Table 1. — Isotropic Substances. 



Substance. 



NaF» 



(NH4)2SiF6 



CaF2 



NaAl(S04)2.12H20 



2Na3P04.NaF.19H20 



NH3(CH3)A1(S04)2.12H20 



KA1(S04)2.12H20 



EbAl(S04)2.12H«0 



CsAl(S04)o.l2H20 



63 J p. ct. ammonium alum+36i- p. ct. 



potassium alum 



NH4A1(S04)2.12H20 



RbTi(S04)2.12H20 



EbIn(S04)2.12H20 



CsGa(S04)2.12H20 



CsIn(S04)2.12H20 



KGa(S04)2.12H20 



RbGa(S04)2.12H20 



NH4Tn(S04)2.12H20 



NH4Ga(S04)2.12H?0 



2Na3As04.NaF.19H20 



CaTi(S04)2.12H20 



CsMn(S04)2.12H20 



KAl(Se04)2.12H20 



CsCr(S04)2.12H20 



KCr(S04)2.12H20 



RbCr(S04)2.12H20> 



KFe(S04)2.12H20 



RbFe(S04)2l2H20 



CsFe(S04)2.12HoO 



NH4Cr(S04)2.12H20 



NH4Fe(S04)2.12H20 

 KCl, 



Refractive 

 index Wd. 



RbCl 



Thallium alum.+3 p. ct. potassium 



alum 



T1A1(S04)2.12H20 



RbRh(S04)2.12H20 



1.336 

 1. 3696 

 1. 4339 

 1. 4388 

 1. 4519 

 1. 4541 

 1. 4562 

 1. 4566 

 1. 4587 



1. 4586 

 1. 4594 

 1. 462-1. 465 

 (red). 



1. 4638 

 1. 4649 



1. 4652 



1. 4653 

 1. 4658 

 1.4664 

 1. 4684 

 1. 4693 

 1. 4736 



1. 479-1. 487 

 (red). 

 1. 4801 

 1. 4810 

 1.4814 

 1.4815 

 1.4817 

 1. 4823 

 1. 4839 

 1. 4842 

 1.4854 

 1. 4903 

 1. 4930 



1. 4964 



1. 4976 



:. 5004-1. 5023 



Substance. 



TlGa(S04)2.12H20... 

 RbFe(Se04)2.12H20.. 

 CsRh(S04)2.12H20... 

 NH4Rh(S04)2.12H20. 

 CsFe(Se04)'..12H20.., 



Na8(MgCl)(C03)2 



NaC103 



TlCr(S04)'>.12H20.... 

 2Na3V04.NaF.19H20 

 TlFe(SO4)2.12Ho0.... 

 Na8VO4.10H2O 



K2Mg2(S04)8 



NaCl 



TlRh(S04)2.12H20... 



RbBr 



KBr 



Sr(NOs)2 



Ba(N03)2 



NaBrOa 



CsCl 



NHjCl 



Rbl 



K2SnCl6 



KI 



CsBr 



NH4I 



MgO 



AS2O8 



Pb(NOk)2 



Csl 



AgCl 



Sb203 



P (yellow) 



NiO 



CuT 



ZnS 



CU2O 



Si 



Refractive 

 index no. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



1. 



2. 



2. 



2. 

 f (red) 2! 

 \ (blue) 2. 



5066 



5070 



5077 



5103 



5116 



5144 



5151 



.5228 



5230 



5236 



5305 



5329 



5442 



5480 



5530 



5590 



5667 



5717 



5943 



6418 



6420 



6474 



6574 



6770 



6984 



7031 



7364 



75.50 



7838 



7876 



0710" 



0870 



1168 



180 



390 



.3460 



3692 



7050 



7360 



" Personal communication, G. L. Keenan. 



Table 2. — Uniaxial Positive Substances. 



Substance. 



MgSiF6.6H20 . 

 MnSiF6.6H20. 

 FeSiF6.6H20.. 



MgF2 



CoSiF6.6H20. 



System. 



Trig.... 

 Trig.... 

 Trig.... 

 Tetrag. 

 Trig.... 



ZnSiF6.6H20 1 Trig. 



NiSiF6.6H20 



Na3P04.12H20 



X2S2O6 



Na3As04.12HoO 



Rb2S206 



NaK3(S04)2 



Na3V04.12H20 



lSra3VO4.10H2O 



Fe2(S04)3.9H20 



MgPt(CN)4.7H20 a 



Mg(0H)2 



Ca(CeF)2(C03)3 



MgSnCl6.6H20 



K4CdGl6 



(NH4)4CdCl6 



CaSiOsft 



PbS206.4H20 



(NH4)3PdS03Cl3.H20 c. 



Li2Si03'i 



Be2Si04 



4NH3.IrCl3.H2O 



CuH2Si04 



P(C2H,)iI 



Trig 



Trig 



Trig 



Trig 



Trig 



Trig 



Trig : 



Hexag. modification . 



Ditrig 



Tetrag 



Trig 



Dihex 



Trig 



Ditfig 



Ditrig 



Hexag. modification. 



Trig 



Trig 



Rhomb 



Rhomb 



Trig 



Rhomb 



Trig 



Trig. 



CaCeF(C03)2 



a Strong pleochroism: 1 opt. ax. more. D axis less bluish. 

 b Anomalously biaxial, but always with very small ax. angle. 

 o) Reddish yellow; « dark carmine red. 

 d Indices approximate. 



1.3439 

 1.3570 

 1.3638 

 1. 3780 

 1. 3817(C) 

 1.3824 

 1.3910 

 1. 4458 

 1. 4550 

 1.4567 

 1.4574 

 1. 4901 

 1. 5095 

 1. 5398 

 1.5519 

 1.553- 

 1.5590 

 (red). 

 1. 5690 

 1. 5885 

 1.5906 

 1.6038 

 1.6150 

 1.63.51 

 1.6430 

 1.65 

 1.6542 

 1. 6576 

 1. 6580 

 1.6600 

 (orange). 

 1. 6742 



1.3602 

 1.3742 

 1.3848 

 1.3897 

 1.3872(C) 

 1. 3956 

 1. 4066 

 1. 4524 

 1.5153 

 1.4662 

 1.5078 

 1. 4996 

 1.5232 

 1.5475 

 1. 5575 

 1.553 + 

 1.5795 

 (red). 

 1. 6700 

 1.5970 

 1.5907 

 1. 6042 

 1. 6360 

 1.6531 



1.67 

 1. 6700 

 1.6666 

 1. 7079 

 1.6680 

 (orange). 

 1.7701 



0. 0163 

 . 0172 

 .0210 

 .0117 

 . 0055 

 .0132 

 .0156 

 .0036 

 .0603 

 .0095 

 .0504 

 .0095 

 • . 0137 

 .0077 

 . 0050 

 Very weak. 

 .0205 



.101 

 .0085 

 .0001 

 .0004 

 .021 

 .0180 

 Strong. 

 .02 

 .0158 

 .0090 

 .0499 

 .008 



.0959 



