SERRET—SIXTEEN. 
130 
Serret, P. : syzygetic relations, xm, 224. 
Servois, J. F. : multiple algebra, xn, 468. 
Sets : homology of, in, 35. 
Sextactic Points: and plane curves, v, 545, vi, 217; and reciprocants, v, 618. 
Sextactic Reciprocant : xm, 387. 
Sextic: binary, and quintics, vi, 190; unicursal, vi, 248; and cubic curves in pencil of six lines, vi, 
593—4 ; the anharmonic-ratio, vii, 314—5 ; bicursal, ix, 551, 581—6 ; tricircular, ix, 562—70 ; 
numerical generating function, x, 394—6. 
Sextic Cone: circumscribed to quartic surface, vii, 265; and nodes, table, vn, 291. 
Sextic Curves : foci of conics, vn, 1—4 ; rational transformation, vn, 236—8 ; and nodes, vn, 256—7 ; 
and quartic surfaces, vii, 267—71 ; mechanical description, vm, 138—44 ; with five double points, 
ix, 504—7. 
Sextic Developable: v, 279—83, 511—9, vi, 87—100. 
Sextic Function : and Abelian functions, xi, 483. 
Sextic Resolvent : Jacobian, iv, 310, xi, 389—401, xii, 493—9. 
Sextic Resolvent Equations : of Jacobi and Kronecker, xm, 473—9. 
Sextic Seminvariants : and perpétuants, xm, 317. 
Sextic, Spherical: and oval, v, 469. 
Sextic Syzygies: xn, 257—62, 273. 
Sextic Torse (see Torse, on a certain Sextic, also Torses). 
Shanks, W. : log 2, xi, 70. 
Sharp: the term, vm, 406—8, xm, 265, 291, 304—6, 362. 
Sharp-cone : the term, vm, 102. 
Sheets: roots in algebraic equations, iv, 116—9; cubic curves, iv, 120—2. 
Shell: formulae for potential of, ix, 266—7; attraction of ellipsoidal, on exterior point, ix, 302—11. 
Sibi-reciprocal Surfaces : vi, 21, x, 252—5. 
Siebeck, F. H. : binodal quartic and graphical representation of the elliptic functions, xm, 10. 
Signs : rule of, iv, 595—6, xi, 492. 
Sign Symbols: theorems, vm, 535—7. 
Simple Cone : defined, v, 402, 404, 551. 
Simple Groups: xm, 533. 
Simultaneous Equations : Jacobi’s theorem in, xn, 39. 
Simultaneous Roots of Two Equations: Jacobi’s theorem in, xii, 123—5. 
Sines, Multiple : x, l—2. 
Single Theta Functions: memoir, x, 473, 476—97; and double theta functions, x, 155—6, 186—9; 
and elliptic functions, xi, 250—1 ; linear transformation, xii, 50—5. 
Singular Curve : on surface, vn, 244. 
Singularities : of curves and developables, I, 208 ; of tortuous curves, I, 500 ; of surfaces, ii, 2»—32, 
IV, 21—7, VI, 123—8, 334—41, 354, 582—5, VIII, 394—8, XI, 225—6, 630—1 ; of plane curves, 
v, 424—6, 476—7, 520—8, 619, vi, 3, xi, 30—6; of curves and torses, v, 516; compound, v, 525; 
of curves in space, v, 613 ; of cubic surfaces, vi, 363 ; reciprocal surfaces, vi, 596—601 ; of curves, 
xi, 486—70. 
Singular Point : for differential equations, xii, 395 ; integrals in domain of, xii, 395—402. 
Singular Solutions of Differential Equations: iv, 426—7; of first order, vm, 529—34 x, 19—24. 
Six Coordinates of a Line (see Coordinates, Six of a Line). 
Six Lines: Sylvester’s involution of, vn, 66. 
Six-pointic Contact : on cubic, iv, 207. 
Sixteen-nodal Quartic Surfaces: i, 587, v, 431—7, vi, 126—7, 281—4, x, 157—65, iso—3, 437—40, 
464, 548—51, 604, xii, .95—7.