"Of no little importance are Euler's labors in analytical mechanics. ...He worked out the theory of the rotation of a …"

"Let the mass of the projectile be M, and let its speed be v while being moved over an infinitesimal distance ds. The …"

"After having worked in the theory of light and gravitation, he announced, in 1744, a new minimum principle, the Princ…"

"The minimum principle that unified the knowledge of light, gravitation, and electricity of Hamilton's time no longer …"

"Maupertuis really had no principle, properly speaking, but only a vague formula, which was forced to do duty as the e…"

"Euler's view is, that the purposes of the phenomena of nature afford as good a basis of explanation as their causes. …"

"I must now explain what I mean by the quantity of action. A certain action is necessary for the carrying of a body fr…"

"After so many great men have worked on this subject, I almost do not dare to say that I have discovered the universal…"

"When a change occurs in Nature, the quantity of action necessary for that change is as small as possible. The quantit…"

"The first formulation of (part of) mechanics by means of a variational principle... is due to Maupertuis in 1746 in a…"