85 
CONICS-COORDINATES. 
five conditions of contact, vn, 40; three, problem and solution, vn, 595; and absolute, vm, 
31—44; theorem of eight points on, vm, 92—4 ; cuspidal, of centro-surface, vm, 352—7; reciprocal 
of equation, vm, 522—3; theory of confocal, vm, 556—7; sets of four points on, x, 569; and 
lines, x, 602; degenerate forms of curves, xi, 218—20; the term, xi, 460; in Ency. Brit., xi, 
561—4; analytical geometrical note on, xn, 424; / and c, xiii, 11—2; non-existence of special 
group of points, xiii, 212; the nine-point circle, xiii, 517—9. 
Conics, Spherical: theorem relating to, iv, 428; and stereographic projection, v, 106—9; (see also 
Polyzomal curves). 
Conics which pass through: four points, hi, 136—8; four foci of given conic, iv, 505—9; three 
given points and touch one line, v, 258—64; two given points and touch two given lines, vi, 
43—50; two given points and touch given conic, vi, 245—9. 
Conic Torus: the, ix, 519—21. 
Conjugate Integrals: Hamiltonian, x, 113—5. 
Conjugates: table of, and seminvariants, xiii, 303, 307. 
Connected Areas: xi, 7. 
Connective: of discriminant, n, 529. 
Connective Covariant of two Quantics: defined, n, 515. 
Conormal Correspondence: of vicinal surfaces, vm, 301—8. 
Constants: number of, in special equations, xi, 14—6. 
Constructive Geometry: vn, 27. 
Contacts: problem of, I, 522—31 ; the term, vn, 546. 
Content: Ball on theory of, n, 606. 
Continuous Function: the term, xi, 539. 
Contour: lines, iv, 108—11, 609; defined, v, 63. 
Contracovariants: defined, iv, 329. 
Contractible Squarewise: the term, xiii, 179. 
Contragredient: the term, iv, 607—8, xiii, 46. 
Contraprovectant: defined, n, 514. 
Contraprovector: the term, n, 514. 
Contrasect: the term, xiii, 485. 
Contravariant: the term, n, 320, xiii, 46; of ternary cubic, iv, 325. 
Convergence : condition of uniform, xiii, 342—5. 
Converging Series: product of, ix, 61. 
Convertible Matrices (see Matrices). 
Convolution: the term, vi, 461—2. 
Coordinates: in general theory of geometry, n, 604—6; as functions of parameters, vi, 1—2; polyzomal 
curves, vi, 498—9, 537; trilinear, xi, 467 ; Pliicker, xi, 467; degenerate curves, xi, 488—9; in Ency. 
Brit., xi, 546—51, 566—7; illustrative of geometry, xi, 552—6; curvilinear, in Ency. Brit., xi, 
637 ; versus quaternions, xiii, 541—4. 
Coordinates of a Line: x, 603, xi, 468. 
Coordinates of Points: expressions for, v, 517—8 ; lines and planes, non-Euclidian geometry, xiii, 489—91. 
Coordinates, Six of a Line: vn, 66—98, vm, 401, x, 287, xn, 42—3, 321; introductory, vn, 66; de 
finition and general notions, vn, 67—9; elementary theorems, vn, 69—73; geometrical considerations, 
vii, 73—5; linear relations between six coordinates, vn, 75—85; geometrical property of an in 
volution of six lines, vn, 85; four given lines and twofold tractor, vn, 85—6; hyperboloid through 
three given lines, vn, 86—8; six coordinates defined as absolute magnitudes, vn, 88—9, 96—7; 
statical and kinematical applications, vn, 89—95; transformation of coordinates, vn, 95—6 ; formulae 
of transformation, vn, 97—8. 
Coordinates, Spherical: theory of, and systems of equations, i, 213—23.