482 
MEASUREMENTS OF CRYSTALS. 
QUARTZ. (Continued.) 
Figs. 167, 168 and 173, twin crystals. 
Figs. 174, 175. 
P on o .. 128° 20' 
Fig. 181. 
P on x 
r on x 
x on z 
148°42' 
167 56 
125 11 
