444 PROCEEDINGS OF THE AMERICAN ACADEMY. 





T, — i I (254). On two crystals, with small distinct faces, bright, 

 and giving good reflections (Figures 7 and 8). 



<P p 



Crystal 8 —24° 41' 56° 48' good. 



12 —24 27 56 42 " 

 Calculated' —24 18 56 45 



U, f 3 ^ (236). With three faces on two crystals. Faces distinct, but 

 small, and reflections indistinct (Figure 8). 



<t> p 



Crystal 8 37° 18' 34° 42' poor. 



8 38 16 34 52 " (in twin position). 



13 37 32 35 13 " 

 Calculated 37 53 35 10 



The following forms have been observed once or more as faces or re- 

 flections, but owing to their poor quality, or to the too great discrepancy 

 between observations and calculated values, or for other reasons, they 

 are considered as requiring confirmation : 



X, 0£ (013). Not observed as a distinct face (Figure 5). 



r, Of (034). Observed three times, not as a definite face. 



<P p 



Crystal 1 0° 3s' 38° 48' (in twin position). 



3 45 40 25 " " 



6 34 38 45 



Calculated 35 39 50 



