CRYSTALLOGRAPHY. 



12. 



15. 



f% 



^CT 



H W 



Many more figures might be given for this one species, py- 

 tite. The various forms or planes in any such case have, it is 

 true, mutually dependent relations — a fact often expressed by 

 saying that they have a common fundamental form. But it ia 

 none the less a remarkable fact, giving profound interest to the 

 subject, that the attraction, while having this degree of unicy 

 in any species, still, under each, admits of the nrjLltitudinous 

 variations needed to produce so diverse results. 



At the time of crystallization the material is usually in a 



