On reciprocal figures, frames and diagrams of forces

James Clerk Maxwell's paper describing a method for calculating stress in a structure.

Date: Written in 1869.
Publication: Transactions of the Royal Society of Edinburgh, Volume 26, Pages 1-40, Plates 1-3, 1872.

Preceding the text of this paper by James Clerk Maxwell are three pages of diagrams of forces.

In his paper, Maxwell states that he proposes to investigate:

'... a different kind of geometrical reciprocity, which is capable of considerable development, and can be applied to the solution of mechanical problems.'

He goes on to describe this 'graphic method' which engineers could use to calculate stress in a structure. He discusses applying the graphic method to cases of continuous stress, as well as the symbolical method of calculation.

Maxwell read his paper on reciprocal figures to the Royal Society of Edinburgh on 7 February 1870.

The article won the Keith Prize. 22nd biennial period, 1869-1871