■'«*^'«(6 136° 40'; ac 118"; ad 90» ; 6' e about 176^ a salient' 

 angle resulting, I conclude, from the composition of two crys- 

 tal.'' ■" '"" 



ilJiv/ ^aohulv 



'\o Iff , ^ ^ , 



vA ///MWW ■.'xUiiua 



. // rioii 



" No. 2 is evidently a compound crystal, but I must have 

 better means than the single crystal has aiforded, to be en- 

 abled to discover the primary form. I do not observe any ' 

 rings in looking perpendicularly through a and the parallel 

 plane, which, although the crystal is only translucent, I think 

 t should do if the primary form were a rhomboid, or Aom- 

 bohedron as now called. The lines represented on the faces ' 

 of No. 2. present bold salient and re-entering angles. The ' 

 only appearance of cleavage, I have found in breaking the 

 sma-11 crystal, is parallel to the lateral planes d of the hexago- 

 nal prism, but I am not certain that these are more than 

 planes of composition of intersecting crystals," '.ui ua 



CItemical Examination of Greenockite., or Sulphur et of Cadhm- 

 uin. By Arthur Connell, Esq., F.R.S.E. (Communieated ' 



by the Author). :'.. 



A fragment of Greenockite, heated in a glass tube, decre-- 

 pitated and acquired a fine carmine red colovu, and, on cool- 

 ing, recovered its vellow tint. At a red heat it did notfusd ' 

 or volatilize. It gave off no moisture. ', 



In powder, it was readily soluble in heated muriatic acid, 

 Avith strong odour of sulphuretted hydrogen. Carbonate of 

 soda caused a white precipitate soluble in ammonia. The mu- ; 

 riatic solution, by evaporation, afforded a white prismatic crys-"^ 

 tallization, not deliquescing in an ordinary atmosphere. This 

 character distinguished the mineral from zinc-blende, which 

 it resembles, and supjrested the idea that it might be stdphftj^. 



