Abstract
An outstanding geometrical problem of the least half of the nineteenth century was to discover a linkage mechanism for drawing a straight line. In 1864, a solution (Peaucellier Cell) was finally found by a French army officer Peaucellier (1832~1913). The Peaucellier Cell was based upon the fact that the inverse of a circle through the center of inversion is a straight line. The subject of linkages became quite fashionable among geometer, and many linkages were found for constructing special curves. This paper presents the design of linkages under Cabri Geometry Ⅱ, interactive dynamic software of geometry. It is divided into five sections. The first section is to introduce definition and preliminary. The second section is about the general theorem of linkages. The third and fourth sections are to introduce some basic linkages (Peaucellier, Hart's, and Kempe's Cell), and some properties for linkage, respectively. The last section is the drawing of curves with linkages. Further, I also put the content of this paper on this website: http:// apollonius math nthu.edu.tw/d2/g913259web Here anyone can see my achievement easily and the application of dynamic geometry.