1903.] WRIGHT—CRYSTALLOGRAPHIC PROPERTIES. 241 
The character of the three pyramidal faces z, v, f, is uniform and 
unvaried. Long narrow faces exhiting occasionally fine strize 
parallel to the basal edge, particularly on the hollow crystals. 
The form z, 2 o (2073) appeared on three of the measured crys- 
tals, v, 10 (1071) on ten, and the form 4, 20 (2021) on ten and 
on one crystal as the only pyramid (Fig. 5). 
The form x, 4 (1172), like a, «© 0, occurred but once and on | 
the same crystal with the latter, as a small rounded face (Fig. 4). 
Its reflexion signal was approximately in its correct position. The 
form is considered probable. 
Fig. 1 gives a gnomonic projection of all the observed forms on 
domeykite. 
Types of Crystal Habit.—Fig. 2 (crystal No 1, dimensions 
1.2 < 1.2 X 0.3 mm.) illustrates the first and most common type 
of domeykite crystals. Flat, thin tabular cystals with the 
forms 0, © 0, Io, 20, the last three as narrow, sharp faces fre- 
quently striated horizontally. These artificial crystals are occa- 
