1903.] WRIGHT—CRYSTALLOGRAPHIC PROPERTIES. 239 
as a sharp, perhaps vicinal face on crystal No. 4; and? 41 (1232), 
observed once as a small rounded face (crystal No. 3). 
Element : fp = 1.0259 + 0.0006 
Fo 1 10,5085)" 
@:c, =1: 1.539 
The element p, was calculated from the mean of the angles of 
27 sharp, single reflecting pyramidal faces of the measured crystals, 
no attempt being made to separate the different types of crystal 
habit. The form zv, 10 furnished 12 of these faces (g = 30° 00’, 
p = 45° 44’, possible error + 1’), the form /, 20, 11 faces (g = 
30° 00’, p = 64° or’, possible error + 3’), and the form 2, 20, 4 
ftees) (== 30" .00',, p == 34° 22’, possible error = 1’); 
Table of Angles.’ 
C1539 c==018721|lg @—005135\lg f,—=OO1 112 wemB 235 =H) (G,) 
- - | Bra- : : - ad 
ae vais | ° p 50 | 7% 5 Cee oak @, y == ig p 
(#29) 
° ° ° ° ° fe} 
c o 0001) — | 0.00} 0.00) 0.00} 0.00) 0.00 fe} |. «0 fo) 
?a@ «  |1 1 2.0|30,00/90,00/90,00|90.00} 30.00/60.00; 0/.5 773 oo 00 
6 | © 0 |107 0) 0,00]90.00) 0.00|90.00} 0.00|g0.00 oO oe eo 
2 2 0 |2028| 0,00/34.23) 0.00/34.23) 0.00/34.23 fo) |0/.6840|0/.6840 
v I 0 |1011] 0,00/45.44| 0.00|45.44| 0.00|45.44 fo) '1/,0259|1/.0259 
Pp 2 0 |2021] 0,00/64.01|} 0.00|64.01| 0.00)64.01 fe) 2/,0518/2/.0518 
2% 4 1 1 2 2|30.00/41.37/23.57|37-34|19.23|35.06| 0/.4443 |0/.7730/0/.8885 
IOUDO db 
DESCRIPTION OF THE INDIVIDUAL Forms. 
1. The form ¢, o (ooor) was absent on only one crystal (No. 9, 
Fig. 4). It has sharp hexagonal outline, splendent metallic luster 
and is usually perfectly flat, except in the larger crystals where it 
is frequently uneven and undulating. If observed under a micro- 
1 @ : ¢) denotes the axial relation of the pyramid 10 (IfoT1) and a: c¢, those of 
the pyramid 1 (1121). See V. Goldschmidt, /udex der Krystalformen, Vol. i, 
P= 35> 
2 Calculated according to scheme given in Winkeltabellen, von V. Gold- 
schmidt, 
