a Compound of Iodine and Codeine. 123 



face is entirely absent. The faces d and d' may be considered 

 as the macrodiagonal hemidomata + r H/2, and — / H/2, 

 of which, owing to the un symmetrical development of 

 the crystals, the opposite faces + / H/2 and — r H 2, are 

 wanting. In the position of the acute edge next the angle 

 g, the plates are frequently united together so that that edge 

 disappears, and the crystals then diverge in the form of a 

 fan. The size of the crystals I examined was about three 

 lines on the longest edge, and their thickness about a sixth 

 of a line. 



I am indebted to Mr Franz Foetterle, Inspector of Mines, 

 for the following measurements, taken with the reflecting 

 goniometer : — 



angles :- 



The combination edge o d forms, with the combination 

 edge om' lying to its right, an angle k of 69° 9', and with 

 that to the left omsm angle of 82° 49', and the base conse- 

 quently assumes a rhomboidal form when lines are drawn 

 through the obtuse angles parallel to these edges. The 

 obtuse angles of the rhomboid are = 143° 58', the acute 

 = 36° 2'; the diagonals intersect each other under angles of 

 104° 24' and 75° 36'; they divide the obtuse angle into two 

 angles of 83° 10' and 61° 3', and the acute angle into two of 

 21° 35' and 14*= 27'. 



