Stubborn rigour. Doomed rigour.
[Footnote: See PI. LXII, No. 2, the two upper pen and ink drawings. The originals, in the Windsor collection are slightly washed with colour. The background is blue sky; the plough and the instrument with the compass are reddish brown, the sun is tinted yellow].
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.