COMOMENT-CONICS. 
84 
Comoment: non-Euclidian geometry, xiii, 481—9. 
Compass: Mascheroni’s geometry of the, xii, 314—7. 
Complex (see Surfaces). 
Complex Cone: (cubic) defined, v, 402, 404, 551. 
Complexes of Lines: iv, 618; through twisted quartic, xn, 428—31. 
Complex Multiplication: in elliptic functions, xn, 556—7; (see also Multiplication). 
Complex Quantities: logarithms of, vi, 14—8. 
Complex Variables: and conformal representation, x, 316—23; Newton-Fourier theorem for, x, 405—6; 
(see also Function, Newton-Fourier theorem). 
Composition: of quadratic forms, i, 532; of singularities, v, 619 ; of rotations, vi, 24—6. 
Compound Combinations (see Combinatory analysis). 
Compound Singularities: v, 525. 
Conchoid: the term, xi, 460. 
Concomitant: the term, iv, 607—8, xiii, 46. 
Concomitant-system: of quintic, x, 342. 
Cone: touching six lines, vm, 401—3 ; formulae for potentials of, ix, 266—7. 
Cones: through cubic curve in space, in, 219—21; note on cubic, iv, 120—2; and cubic centres, iv, 
173—8, 179—81; and cubic curves, v, 284—8; kinds of cubic, v, 401—15; and representation of 
curve, v, 552; circumscribed sextic, vn, 139; satisfying six conditions, vm, 99—137 ; the term 
asymptotic, xiii, 232; characteristic n and theory of curves in space, xiii, 468—72. 
Configurations: algebraic, by Hilbert, vi, 596. 
Conformal Representation: ix, 609—11, xi, 442, xn, 104; by function arc sin (x 4- iy), x, 290—2; 
mechanical constructions, x, 406; example, xi, 38; theorem, xi, 78—81; and Schwarzian theory, xr, 
169—76; imaginary quantities, xi, 258—60; (see also Orthomorphosis, Representation, Transformation). 
Congregate: the word, x, 339, 345. 
Congruences: in Ency. Brit., xi, 628, 634—5; analytical theory, xiii, 228—30. 
Conic: theorem of triangle and line, v, 100—2; theorem of eight points on a, v, 427—30; formula for 
intersections of line and conic, v, 500—4; four points on, v, 571; defined by five conditions, vii, 
546, 552 ; through three points and with double contact, vn, 554; foci of, vn, 571; and four 
points, vn, 581, 587; construction, vn, 592; (2, 2) correspondence of points on, vm, 14—21; and 
cubic, x, 605—7; Monge’s differential equation, xn, 393; focals of quadric surface, xm, 54. 
Conic-node: the term, vi, 360. 
Conics, Analytical Theory of: iv, 395—419; relating to single conic, iv, 396—402; ditto with point 
or line, iv, 402—12; ditto with tangent of conic of double contact, iv, 413; relating to two conics, 
iv, 416—9. 
Conics: general theory of, i, 519—21; inscribed in a quadric surface, i, 557—63; in-and- 
circumscribed polygon, n, 142—4, iv, 295—9; two dimensional geometry, n, 575—83, 586—92; 
forms of equations of, hi, 86—90; area of, and trilinear equation second degree, m, 143—8; 
normals of, iv, 74—7; of five-pointic contact of plane curve, iv, 207—39; which touch four 
lines, iv, 429—31; system having double contact, iv, 456—9, vn, 568 ; theorem in, iv, 481—3; 
touching curves, v, 31—2, 552 ; four inscribed in same conic and passing through same three points, 
v, 131—2; contact of, v, 552; and rectangular hyperbolas, v, 554; problem, v, 562, 582; tan 
gents of, v, 578; intersection of, v, 582; triangle and, v, 593; and cubic, v, 608; drawing 
of, vi, 19; locus from two, vi, 27—34; theorem of four which touch same two lines and 
pass through same four points, vi, 35—9; which touch cuspidal cubic, vi, 249—53; contact of 
third order with given cuspidal cubic and double contact with given cubic, vi, 253—6 ; Zeuthen’s 
forms for characteristics of conics which satisfy four conditions, vi, 256—S; correspondence, 
and those which satisfy given conditions, are at least arbitrary, vi, 268—71; five conditions 
of contact with a given curve, vi, 272—91 ; foci of, vi, 517—9, vn, 1—4; determined by