Ellipsoid Small 320×261 Medium 640×523 Large 1024×837 Download Tiff Original 2400×1961 | (174.7 KB) Description Each section is an ellipse. The surface is generated by an ellipse moving parallel to itself along two ellipses as directices. Keywords directrix, ellipse, Parallel Galleries Analytical Geometry Source: Encyclopaedia Britannica (New York: The Encyclopaedia Britannica Company, 1910) 11:719
