Research on the largest and the smallest which are found in the action of forces
Euler shows that any discrete system obeys the Maupertuis principle; from this result, he derives the general equation for the balance of moments in a plane elastica, which includes the general catenary as a special case. He also proves that Daniel Bernoulli's principle for the elastica that is free of distributed loads is also a special case of this general equation. (Based on Clifford Truesdell's An idiot's fugitive essays on science: methods, criticisms, training, circumstances.)
Original Source Citation
Mémoires de l'académie des sciences de Berlin, Volume 4, pp. 149-188.
Opera Omnia Citation
Series 2, Volume 5, pp.1-37.