CYCLOTOMY—DERIVATION. 
90 
Cyclotomy: (Kreistheilung), xi, 58, 86. 
Cylinder: in Ency. Brit., xi, 572—3; Archimedes’ theorem for surface, xn, 56—7. 
d’Alembert, J. le R.: rotation of solid body, iv, 567, 586; geometric paradox, xn, 305—6. 
Dandelin, G. P.: theory of, and on caustics, n, 339—40; wave surface, iv, 433—4. 
Darboux, G.: powers of circles and spheres, i, 581; the torus, vn, 247; quartic surfaces, vm, 262; 
cyclide, ix, 64; continuous function, xi, 539; curves of curvature, xn, 615; quartics, xm, 13. 
Davis, W. Barrett: calculations by, in, 361, iv, 376; quantic covariants, vn, 335; Sohnke’s modular 
equations, ix, 543. 
Deblais: theory of, xi, 417—20, 449, 587. 
de Bruno, Fait: invariants of degree 12 belonging to quintic, n, 314; symmetric functions, n, 602; 
canonical forms, iv, 52; elimination, iv, 608. 
Decadianome: the term, vii, 134; and symmetroid, vn, 256. 
Decapitation: and seminvariants, xn, 248—50. 
Decomposition: linear differential equations and theory of, xn, 402, 403—7. 
Dedekind, J. W. R.: probabilities, n, 594—8, v, 80; modular function, xm, 338—41. 
Def: the abbreviation in groups, xm, 120. 
Deficiency: and genus of curve, v, 467, 517, 619; of curves, v, 618, vm, 391, xi, 450; the term, 
vi, 2; and transformation, vi, 3, xi, 482—5; the term applied to surface, vi, 356; of certain 
surfaces, vm, 394—7, xi, 230; surfaces of negative, vm, 397; of sextic curve, ix, 504—7 ; of curve 
and Abelian integrals, xi, 30—6. 
Definite Integrals: with complex variables, i, 181—2, 310; differentiation and evaluation, i, 267—72, 
587; on a, iv, 28—9; note on Glaisher’s paper, vm, 1 ; note on two, ix, 56—63; (see also 
Attractions, Potentials, Prepotentials). 
Definitions (see the word desired). 
Deformation: the term, i, 234; of hyperboloid, xi, 66—7; of skew surfaces, xi, 317—22, 331; (see 
also Surfaces). 
Degeneracy : of surfaces, v, 98—9 ; of scrolls, v, 201—3 ; of curves, xi, 218—20. 
Degen’s Mathematical Tables: iv, 40, ix, 478—9, x, 586; report of British Association Committee, 
xm, 430—67. 
Deg-order: the term, x, 339. 
Degrees: of qualities defined, n, 221. 
Degrees, Honorary: conferred on Cayley, vm, xx—xxi; conferred on Sylvester, xm, 43. 
de Jonqui^res, E.: cubic curves, i, 586, iv, 496; on curves, iv, 454; curves which satisfy given 
conditions, vi, 191, 192, vn, 41—3; form of equation of curves of a series of given index, vi, 
242—3 ; question from formula, vi, 258—62; points on cubic curve, vn, 550, 553; correspondence, 
xi, 486. 
de la Goupilliere, H.: inertia, iv, 566. 
de la Gournerie, M.: tetrahedral scrolls, vn, 48—53; scrolls, vn, 54; quartic and quintic surfaces, 
vn, 246, 247, 251; torus, vm, 25 ; octic surfaces, x, 81. 
Delambre, J. B. J.: Tables du Soleil, hi, 474. 
Delaunay, C. E.: lunar theory, vn, 357, 372, 376, 528—33, 534, ix, 180, xm, 206—7. 
de Morgan, A.: root in every algebraic equation, iv, 116—9; root limitation, ix, 39; series, xi, 
623, 627; and Sylvester, xm, 45. 
Denumerant: illustrated, iv, 169—70. 
Denumerate: defined, iv, 241. 
Departure Point: in lunar theory, iii, 19, 270, 295. 
Derivation: of points of cubics, vi, 20; and Ubereinanderschiebung, vii, 34S; and seminvariants, 
xm, 362—5.