Note 629 — Chapter XVI · ON FORM AND MECHANICAL EFFICIENCY

The method of constructing reciprocal diagrams, in which one should represent the outlines of a frame, and the other the system of forces necessary to keep it in equi­lib­rium, was first indicated in Culmann’s Graphische Statik; it was greatly developed soon afterwards by Macquorn Rankine (Phil. Mag. Feb. 1864, and Applied Mechanics, passim), to whom is mainly due the general application of the principle to engineering practice.