378 



Prof. Lewis, On the 



[May 1-1, 



as seen through the paper and turned round so as to bring them 

 into the normal position. Fig. 7 is an inverted copy of the planes 

 on my crystal 7 and Miller's B. Miller's diagram is very like this, 

 excepting that none of the planes in the zone of symmetry are 

 shown. The axial system used is the same as in Fig. 2. In Figs. 

 4, 11 and 12 the plane of symmetry is vertical and directed back 

 and fore. Fig. 13 represents the twin-crystal, and has been already 

 described. 



Calculated. 



S.C, 



aq, 

 «A 



5156 



69 33-6 69 27 



23 43-5 

 40 51 

 50 16 



50 16 



ag, 59 12-5 



at, 



a & 



9fi, 

 fcft 



PA 

 tA, 



a / h l 

 h, (139) 



70 8-6 

 109 51-4 



37 1 

 26 4-9 

 12 47 



38 51-9 

 70 59-5 



ch 44 1 

 ht 25 19-6 

 ct 69 20-6 



109 46 



38 49 

 70 57 



69 17-5 



Strassburg. 



36 21-5 

 36 26-5 

 (36 36) 



63 4316 



63 46 

 (63 56) 

 ir- 116 15'25 



14 39-4 



3155 



15 28-5 

 (15 7) 



69 34 



