CONTENTS. XVII 

 II. OF SIMPLE FORMS Itf PARTICULAR. 



Consideration of Simple Forms, and some of their Geometrical 

 Relations. 



. 50. The Rhombohedron . - . .41 



.51. Pyramids in general . . 43 



. 52. Isosceles Four-sided Pyramids . . 44 



. 53. Scalene Four-sided Pyramids . 45 



. 54. Isosceles Six-sided Pyramids . . 46 



. 55. Scalene Six-sided Pyramids . . 47 



. 56. Scalene Eight-sided Pyramids , . 48 



. 57. The Tetrahedron . . 49 



. 58. The Hexahedron . . * 50 



. 59. The Octahedron . . 50 



. 60. Dodecahedrons in general . . 51 



.61. Trigonal-dodecahedrons . . 51 



. 62. Tetragonal-dodecahedrons . . 52 



. 63. The Monogrammic Tetragonal-dodecahedron- 52 



. 64. Digrammic Tetragonal-dodecahedrons . 53 



. 65. Pentagonal-dodecahedrons . . 54 



. 66. Hexahedral Pentagonal-dodecahedrons . 54 



. 67. Tetrahedral Pentagonal-dodecahedrons . 55 



. 68. Icositetrahedrons in general * . 56 



. 69. Trigonal-icositetrahedrons . . 57 



. 70. Tetrahedral Trigonal-icositetrahedrons . 57 



.71. Hexahedrai Trigonal-icositetrahedrons . 58 



. 72. Octahedral Trigonal-icositetrahedrons .- 59 



. 73. Tetragonal-icositetrahedrons . 59 



. 74. Digrammic Tetragonal-icositetrahedrons . 60 



. 75. Trigrammic Tetragonal-icositetrahedrona 61 



,76- Pentagonal-icositetrahedrons . . 62 



. 77. Tetraconta- octahedrons . . 63 



Consideration of the Connexion among Simple Formr, and of the Re- 

 lations upon which it depends* 



. 78. Observations . . .64 



. 79. Derivation ... 66 



. 80. First Process of Derivation , . 67 



