34 



mulation of flat or plated rhombs, forming truncations upon 

 all the edges. The other figure shows them produced Very 

 widely, with the sharper angles accumulating in a triangle 

 at both ends. This is exemplified in the lower part of 

 the specimen Jig. 2. The Crystal in the middle geome~ 

 trlcal Jigure is also on a large specimen that was in Mr. 

 W. Day's collection. 



This is the Braunspath of the Germans ; but has, how- 

 ever, been sometimes taken for a Tin Ore in Cornwall. 



Mr. W. Day observed that it did not effervesce with acids. 

 It is one of its characters, as a Magnesian Iron Ore, to 

 effervesce very slowly. 



