Plaster Surface Model by Alexander Crum Brown, c 1900. Image
number: 10314747 Alexander Crum Brown (1838-1922), mathematician
and chemist, was professor of mathematics at Edinburgh
University and a prolific maker of mathematical models. This
surface represents the equation: z=3a(x squared - y squared) -
(x cubed + y cubed). Every section made by a plane passing
through the blue line and cutting the surface is an ellipse. -
Image number: - Science Museum/Science & Society Picture Library
- Date taken: - 20 October 2003 14:40 - Image rights: - Science
Museum