MICRO-ANALYSIS. 



843 



Narcotine. Crystals from alcoholic solutions. 



Orthorhombic sphenoidal : a: b: c = 0.532 : i:c. 



Forms observed: Base (001); brachypinacoid (010); and 



sphenoid ( 1 1 1 ) 



Angles: Angle on base between the base-sphenoid edge and 

 brachypinacoid (ooi-iii A 001-010)= 62 (normals). 



Fig. 339. Narcotine: orthorhombic crystals from alcoholic solution. 



Habit : Tabular on the base, elongated along the a axis, the 

 end terminations being the faces of the sphenoid ( 1 1 1 ) , which are 

 inclined to the base. By focussing down upon the crystal it is 

 seen that the edge between the two sphenoid faces slopes in 

 opposite directions at the two ends of the crystal. 



Optical properties: A = a; h = b; C =^ c The axial plane is 

 the brachypinacoid. An interference figure is observed on the 

 base and shows that 2E is large ; apparently Bxa = c; and the 

 optical sign is -\-. 



