424 Hidden and Mackintosh — Poly erase of the Carolinas. 

 Angles (approx.) observed : 



a*s= 151-1° 



b*d= 101 i° 



&.v z= 117^° 



u ~ u 94° 



6 s y 104° 



z*y 140° 



a*q 160° 







These angles closely agree with those recorded for polycrase 

 in Dana's System of Min., p. 523. 



Among the South Carolina crystals we observed several 

 apparent twins, one was parallel to s (021, 24) and another 

 seemingly parallel to d (103, ^-t). Among the Xorth Carolina 

 crystals one was found quite perfectly twinned parallel to 

 u (011, 14). Whenever one of the South Carolina crystals was 

 found terminated at both ends, it was discovered to be hemi- 

 morphic in the occurrence of the planes c (001, O) and 

 d (103, ^-l) and invariably hemihedral as to the plane 

 z (223, 1-f ) ; these two features being new to the species. 



Figures 1 and 2 were, in several instances, combined in the 

 same crystal ; though no crystals were found that had both 

 terminations perfect. Most of the specimens were fragmentary 

 and no crystals or masses were found attached to a matrix. It 

 seems that the one and a quarter kilograms received by us was 

 obtained by washing after the manner of gold mining some 

 kaolinized coarse granite and that this quantity represents 

 nine-tenths of the total amount found at the Marietta, South 

 Carolina, locality (not ten kilos [22 .lbs.] as before stated). 



Concerning the Henderson county, S"orth Carolina, locality 

 nothing noteworthy has been found there recently. 



Our later attempts in the separation of the metallic acids 

 have been somewhat more satisfactory and acting upon a 

 suggestion made to us by Dr. F. A. Genth we made the initial 

 fusion with potassium bi- sulphate (we had previously used the 

 sodium salt). Our results have enabled us to positively 

 identify this mineral as polycrase and to arrive at a very 

 satisfactory formula for the species. 



The corrected analyses of two varieties are as follows :— 



Henderson Co.. X". C. Greenville Co., S. C. 



Oxygen ratio. Oxygen ratio. 



Cbo0 9 19-48 36-35 5-000 19-37 36-14 5-000 



TiO, 29-31 73-27 10-078 28-51 71-27 9"858 



Y 2 3 . etc... 27-55* 30-39) 21-23+ 23*06 ^ 



FeO 2-87 4-00V48-73 6703 2'47 3"43 | 



U0 3 13-77 14-34) 19-47 20'35 I 



PbO ___. 0-46 0-20f 4858b(i9 



FeoOs 0-18 0-33 | 



CaO 0-68 1-21 J 



H,0 5-18 28-83 3"965 4-46 24-78 3'427 



Insol. 0-12 



SiOo 1-01 



98-16# 97-96$ 



At. w't.= 112. f At. w't. = 114-1 



