 | John Fry Heather - 1851 - 228 páginas
...the motion is constantly proportioned to the distance of its centre from the vertex. We observe tbat if in its movement the plane of the circle tends to...lines, and that there is not any surface whose form aud position cannot be completely determined by an exact and complete definition of its mode of generation.... | |
 | Claire J. Farago - 1999 - 526 páginas
..."are the projection 26 of lines of curvature on the surface which they wish to print". Monge argued that "all curved surfaces may be generated by the movement of certain curved 27 lines". Leonardo had expressed a comparable idea in the definitions he adapted from mediaeval sources,... | |
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... so that its radius at each instant is equal to the distance between the two points in which the plane of the circle cuts the axis, and a curve given in space. The generating curve in this way changes at the same time both its form and position. These... 