62732 PROCEEDINGS OF THE EDINBURGH MATHEMATICAL SOCIETY VOLUME XXIX. SESSION 1910-1911. Edinburgh: Printed for the EDINBURGH MATHEMATICAL SOCIETY by INDEX. (1) A proof of Dupin's theorem with some simple illustra- tions of the method employed. (2) Two methods of obtaining Cayley's condition that a family of surfaces may form one of an orthogonal triad. (3) An exten- sion of Dupin's theorem to the case in which a family of surfaces is cut orthogonally by two other families (1) A Property of the Harmonic Triangle of the Complete Quadrangle formed by the four points of contact of the four tangents to the Cubic Curve from a point on (2) The Focal Circles of Circular Cubics PAGE |