estatement of the theorem
29. Four harmonic points
30. Harmonic conjugates
31. Importance of the notion of four harmonic points
32. Projective invariance of four harmonic points
33. Four harmonic lines
34. Four harmonic planes
35. Summary of results
36. Definition of projectivity
37. Correspondence between harmonic conjugates
38. Separation of harmonic conjugates
39. Harmonic conjugate of the point at infinity
40. Projective theorems and metrical theorems. Linear construction
41. Parallels and mid-points
42. Division of segment into equal parts
43. Numerical relations
44. Algebraic formula connecting four harmonic points
45. Further formulae
46. Anharmonic ratio
PROBLEMS
CHAPTER III - COMBINATION OF TWO PROJECTIVELY RELATED FUNDAMENTAL FORMS
47. Superposed fundamental forms. Self-corresponding elements
48. Special case
49. Fundamental theorem. Postulate of continuity
50. Extension of theorem to pencils of rays and planes
51. Projective point-rows having a self-corresponding point in common
52. Point-rows in perspective position
53. Pencils in perspective position
54. Axial pencils in perspective position
55. Point-row of the second order
56. Degeneration of locus
57. Pencils of rays of the second order
58. Degenerate case
59. Cone of the second order
PROBLEMS
CHAPTER IV - POINT-ROWS OF THE SECOND ORDER
60. Point-row of the second order defined
61. Tangent line
62. Determination of the locus
63. Restatement of the problem
64. Solution of the fundamental problem
65. Different constructions for the figure
66. Lines joining four points of the locus to a fifth
67. Restatement of the theorem
68. Further important theorem
69. Pascal's theorem
70. Permutation of points in Pascal's theorem
71. Harmonic points on a point-row of the second order
72. Determination of the locus
73. Circles and conics as point-rows of the second order
74. Conic through five points
75. Tangent to a conic
76. Inscribed quadrangle
77. Inscribed triangle
78. Degenerate conic
PROBLEMS
CHAPTER V - PENCILS OF RAYS OF THE SECOND ORDER
79. Pencil of rays of the second order defined
80. Tangents to a circle
81. Tangents to a conic
82. Generating point-rows lines of the system
83. Determination of the pencil
84. Brianchon's theorem
85. Permutations of lines i