Text-book of general physics, for the use of colleges and scientific schools (1899)
Hastings, Charles Sheldon · Boston: Ginn & company · leaf 162
ne, or the generatrix of the cylinder. When the eccentricity of the ellipse becomes unity by thecoincidence of the fociwith the extremity of themajor axis, the roulettebecomes a semicircle,which is the generatrixof the sphere. A plane may be re-garded as a portion of asphere of infinite radius. In… … Fig. 117.
Physics
Internet Archive · Public Domain Mark 1.0. Free to use for anything.
