56 Mr. F. Field on Ludlamite> 



Calculated angles. 



~aq 



= 107 48 



qa! 



= 72 12 



ap 



= 63 56 



a I 



= 85 16 



P i 



= 21 20 



la' 



= 94 44 



Us 



= 22 33 



~ c m 



= 85 43 



mc f 



= 94 17 



c' q 



= 111 36 



eg 

 in 1 q 



= 68 54 



= 25 23 



cr 



= 44 53 



r m 



= 40 50 



cp 



= 61 38i 



-pin 



= 24 4J 



~qq' 



= 63 24 



dq 



= 58 32 



qd! 



= 121 28 



jq f 



= 116 36 



kq 



= 61 8 



km 



= 110 23 



qm 



= 49 15 



ink 



= 69 37 



r-pn 

 [_pb 



= 53 39 



= 36 21 



Vcl 

 lib 



= 63 12i 



= 26 47i 



Measured angles. 



107° 43' || 108° 



72° 17' || 72° 35' | 72° 39V ||72 ||72° 22' 

 64° 9' 



85° 23' 

 21° 24' 



SQ° 6' 

 93° 54' 

 110° 591111° 52' | 111° 41111° 30' 



69° l'|| 68° 6' to 68° 56' || 68° 30' || 68° 49' 



94° 28' 



25° 29' 



44° 12' 



23° 55 ; 



63° 24' || 63° 38' 



58° 32' | 58° 10J158 14'||58°33' 



116° 36' 116° 321116° 13' 



60° 40' 

 110° 19' 



49° 39 || 49° 57' 

 70° 12' 69° 48' 



The crystals are generally composite — the faces of the forms 

 {l 1 l}and {0 1} being not only furrowed but often also tes- 

 sellated, and, from this cause also, not planes; and occasionally, 

 where the crystal is thin in the direction of the normal to c, 

 the faces q in the zone \c m~] assume a rounded character, and 

 the angle q c offers various values, the limits of which are about 

 64° and 74° 17'. 



Besides the very perfect cleavage parallel to the face 1, 



