7240 



Quadric Surfaces. Equations. Foci 



7240 



Central surface, equation. Graves, C. Ir. Ac. 



P. 4 (1850) 188-. 

 Circular sections. Frost, P. Camb. and Dubl. 



Mth. J. 1 (1846) 133-. 



, in tetrahedral coordinates. Ferrers, 

 N. M. QJ. Mth. 5 (1862) 78-. 



Cone circumscribing quadric surface, equa- 

 tion. Dostor, G. Arch. Mth. Ps. 57 (1875) 



191-. 



Curves on ruled quadrics, Pliicker's coordi- 

 nates. Pliicker,J. Crelle J. 34 (1847) 341-, 



360-. 

 Discussion of equation. Ripert, L. N. A. 



Mth. 17 (1898) 413- . 



Ellipsoid and enveloping cone, equations re- 

 ferred to axes of cone. Scott, G. QJ. Mth. 



6 (1864) 258-. 

 , equation. Hamilton, (Sir) W. R. Ir. Ac. 



P. 4 (1850) 324-. 

 and hyperboloid, equation as resolvent of 



biquadratic equation for focal distances. 



Staude, O. Leip. Mth. Ps. B. 49 (1897) 75-. 

 General equation in oblique coordinates. 



Brisse, C. N. A. Mth. 1 (1882) 207-. 

 , reduction. Thomson, (Sir) W. Camb. 



Mth. J. 4 (1845) 227-. 

 , tetrahedral. Hart, H. L. Mth. S. P. 



12 (1880-81) 135-. 

 Grassmann's methods, applications to quadric 



curves and surfaces. Milller, E. Crelle J. 



Mth. 115 (1895) 234-. 

 Normals, equation determining. Caspary, F. 



Crelle J. Mth. 83 (1877) 72-. 

 Pairs of quadrics inscribed in quadrics. Casey, 



J. [1868] A. Mt. 2 (1868-69) 303-. 

 Partial differential equation. Scherck, . 



[1883] Brem. Ab. 8 (1884) 366-. 

 Planes through 2 given points touching quadric, 



equation. Taylor, H. M. L. Mth. S. P. 11 



(1879-80) 141-. 

 Principal planes, equation. Forestier, C. N. 



A. Mth. 6 (1867) 355-. 

 Quadric through 9 points, equation. Poudra, 



. N. A. Mth. 17 (1858) 297-. 

 Quadrics in Boothian tangential coordinates. 



Jeffery, H. M. QJ. Mth. 9 (1868) 309-. 

 homogeneous linear coordinates. Aschieri, 



F. Mil. I. Lomb. Ed. 9 (1876) 222-. 



in- and circum-scribed to tetrahedron, 

 tetrahedral equations. Haton de la Gou- 

 pilliere, J. N. N. A. Mth. 4 (1865) 241-. 



in plane coordinates. Pittarelli, G. [1874] 



G. Mt. 13 (1875) 204-, 298-. 



4-point tangential coordinates. Jeffery, 



H. M. [1868] QJ. Mth. 10 (1870) 97-. 



quadriplanar coordinates. Jeffery, H. M. 



QJ. Mth. 10 (1870) 1-. 



referred to oblique axes and analytical 

 geometry in space. Zmurko, L. [1865] 

 Wien D. 26 (1867) (2te Ab.) 63-. 



3 tangent planes. Femcick, S. Mathe- 

 matician 2 (1847) 177-. 



touching 3 or 4 planes or inscribed in 

 parallelepiped, equations. Weddle, T. Math- 

 ematician 2 (1847) 258-. 



Reduction. Battaglini, G. Nap. Bd. 1 (1862) 

 79-. 



Rotation surface, criterion for. Mondot, . 



Par. EC. Pol. Cor. 2 (1809-13) 205-. 

 Simplification by transformation of coordi- 

 nates. Gerono, G. C. N. A. Mth. 15 (1856) 



430-. 

 Solution. Poletti, G. Mod. Mm. S. It. 19 



(1821) 30-. 

 Squares of principal axes, equation. Hachette, 



J. N. P. Par. EC. Pol. Cor. 2 (1809-13) 



324-. 

 Stereometric equation. Grassmann, H. [1852] 



Crelle J. 49 (1855) 37-. 

 Systems of planes represented by an equation 



of 2nd degree, number of. Painvin, L. N. 



A. Mth. 10 (1871) 433-. 

 Tangent cone, equation referred to axes. 



Malet, J. C. [1882] Ir. Ac. P. 3 (1883) 594-. 

 Transformations. Mossbrugger, L. Grunert 



Arch. 3 (1843) 430-. 



Foci and Focal Properties of Quadrics. 



Analogy of certain curves to foci. Chasles, M. 



Brux. Ac. Bll. 2 (1835) 35-. 

 Bifocal chords. Butledge, J. Y. Camb. and 



Dubl. Mth. J. 5 (1850) 69-. 

 Cones, oblique, focal properties. Chasles, M. 



Liouv. J. Mth. 2 (1837) 388-. 

 Focal conies. Jellett, J. H. Ir. Ac. P. 2 



(1844) 92-. 



generation of quadrics. Willock, W. A. 

 Camb. and Dubl. Mth. J. 4 (1849) 149-. 



lines. Rees, R. van. Quetelet Cor. Mth. 4 

 (1828) 37- ; 5 (1829) 361-. 



of ellipsoid. lonescu, B. G. [Bucarest 



S. Sc. Bll. 6 (1897)] 165-. 



tangent cone to quadric. Jacobi, 

 C. G. J. Crelle J. 12 (1834) 137-. 



properties. Bobillier, . Quetelet Cor. 

 Mth. 3 (1827) 281-. 



. Maccullagh, J. Ir. Ac. P. 1 (1836-40) 



89- ; 2 (1840-44) 446-. 



. Booth, J. Ph. Mg. 17 (1840) 432-. 



. Heilermann, . N. A. Mth. 17 (1858) 



242- ; Crelle J. 56 (1859) 345-. 

 (Heilermann). Weierstrass, . Berl. 



Mb. (*1858) 270-. 

 (_). Deivulf,. N. A. Mth. 18 (1859) 



46-. 

 . Oliver, J. E. [1865] Am. Ac. P. 7 



(1868) 39-. 



. Milinowski, . Crelle J. Mth. 85 

 (1878) 88. 



. Staude, 0. Mth. A. 27 (1886) 253-; 

 50 (1898) 398-. 



and Jacobi's method of generating an 

 ellipsoid. Townsend, R. Camb. and Dubl. 

 Mth. J. 3 (1848) 1-, 97-, 148-. 



property of conies, analogue. Schroeter, 



H. E. Berl. Ak. Mb. (1877) 594-. 



spheres of quadrics, and focal circles of 

 conies. Haillecourt, A. [1878] Bordeaux 

 S. Sc. Mm. 3 (1880) xi-. 



or umbilical properties. Ingram, J. K. 



Ir. Ac. P. 3 (1847) 442-. 

 Focals. Cayley.A. Mess. Mth. 19 (1890) 113- . 



505 



