XIV TABLE OF CONTENTS. 



Page. 



. 16. Mixed Mineral, 8 



. 17. Properties of Minerals, 9 



. 18. Division of the Natural Properties, 9 



SECTION I. 



. 19. Crystal, 11 



.20. Object of Crystallography, 11 



.21. Planes or Faces, 12 



.22. Edges, 13 



. 23. Plane Angle, . 13 



. 24. Solid Angle, 14 



.25. Similar Faces, 14 



.26. Similar Edges, 14 



. 27. Similar Plane Angles, 14 



.28. Similar Solid Angles, 15 



Considerations upon the connexion among crystals, and the rela- 

 tions upon which it depends. 



OBSERVATIONS. 



. 29. Certain Mineral species affect peculiar crystalline Forms, 16 



. 30. Different Forms in the same species, 16 



. 31. Derivation of different Forms within a species, ... 18 



Consideration of fundamental or primary Forms, and of some of 

 their geometrical relations. 



. 32. Primary Forms, 18 



.33. The Cube, 19 



. 34. The regular Tetrahedron, 19 



.35. The regular Octahedron, 20 



.36. The rhombic Dodecahedron, 21 



