Euler calculated the force of the wheels necessary to raise the water in a reservoir … My mill was carried out geometrically and could not raise a drop of water fifty yards from the reservoir. Vanity of vanities! Vanity of geometry!

— Frederick II of Prussia, Letters of Voltaire and Frederick the Great (1927)

Letter 221 to Voltaire, 25 November 1777, in Richard Aldington's translation.

Topics: mathematics