152 



specimen about many ways. They both come from St. 

 Agnes in Cornwall. 



The lower geometrical figure explains this modification 

 complete, in a position to make it familiar, and to show the 

 placing of the octaedron, which is in the position of the 

 common fractures of all fluates of lime. See Tab. 27. and 

 the latter part of the corresponding description. The upper 

 middle four-sided face in all the figures will be found to agree 

 with the face of the cube common to fluate of lime ; the 

 four sides of which are bevelled off", and the corners, as be- 

 fore mentioned, are parallel to the faces of the octaedron, 

 they forming six square faces of the cube, eight faces of the 

 octaedron, and 24 bevellings; in all 3S faces. 



