of Several Minerals. 71 



shape of rough six-sided pyramids, from Altenberg, near Aix-la- 

 Chapelle, *•*" 



5. Tungsten, a fragment of a yellowish- white translucent crystal, 

 from Schlaggenwald, Bohemia, 6.076 



6. Strontianite, delicate white crystals, aggregated to globular 

 groupes, from Braunsdorf, Saxony, 3.605 



7. Celestine, fragment of a cleavable white translucent mass, 

 engaged in trap, from the Tyrol, 3.858 



8. Witherite, a cleavable variety; yellowish- white, and semitrans- 

 parent, from Anglesark, Lancashire, 4-30 



9. Heavy spar, very thin tabular bluish- white semitransparent 

 crystal, of the form primitive of Haiiy, from Kremnitz, Hungary, 4.412 



10. Heavy spar, a number of small transparent columnar crys- 

 tals, of a white colour, from the Hartz, 4.415 



11. Heavy spar, cleavable, very pale yellowish -grey, and trans- 

 lucent, from Marienberg, Saxony, 4.415 



12. Heavy spar, the variety called prismatic heavy spar by 

 Werner, pale yellow, transparent crystals, very perfectly formed, 

 and imbedded in a large translucent crystal of straight lamellar 

 heavy spar, 4.426 



13. Heavy spar, prisms obtained by cleavage, white, and se- 

 mitransparent, 4.430 



14. Heavy spar, yellowish translucent crystals, from Kremnitz, 4.430 



15. Heavy spar, similar crystals from Beschertgliick, Freiberg, 4.445 



16. Heavy spar, white, semitransparent crystals, from Beschert- 

 gliick, 4.446 



17. Heavy spar, smalt-blue transparent tabular crystals from 

 Offenbanya, Transylvania, 4.473 



18. Heavy spar, a white transparent crystal from Dufton, 

 Westmoreland, 4.480 



19. Heavy spar, in white faintly translucent columnar compo- 

 sitions, commonly called columnar heavy spar, from the aban- 

 doned mine of Lorenz Gegentrum, Freiberg, 4.488 



20. Heavy spar, a single columnar crystal, pale smoke-grey, 

 translucent, from Hiskow near Nissburg, Bohemia, where it 

 occurs with copper-pyrite?, blende, and calcareous spar, in a kind 

 ofseptaria, 4.493 



21. Heavy spar, pale yellow transparent columnar crystals, 

 from Przibram, Bohemia, 4.210 



22. Heavy spar, prisms obtained by cleavage from wax- yellow, 

 translucent, tabular crystals, from Bleiberg, Carinthia, 4.679 



The two last varieties differ so much in their specific gra- 

 vity from each other, and from the rest of the heavy spars, 

 that I was led to suppose the angles of their forms would dif- 

 fer from each other. I had ere then measured the angles of 

 several varieties, which did not agree with each other, and 

 found that these differences in the angles were in close rela- 



