Lune and sector figures, with a note on the ox-bristle
Quadrature sketches share the sheet with a prose curiosity about an ox bristle in still water
The folio is headed by three circular-sector figures and carries a curved-sided lune (falcata) at the right margin, part of Leonardo's running study of the quadrature of lunes that continues on the following leaves; demonstrative notes accompany the figures. The transcription preserved here, however, is a separate prose observation: that the bristle of an ox, placed in still water in summer, seems to take on feeling, life and self-movement, showing fear and flight and feeling pain. Further geometric text on the sheet is not transcribed in this bundle.
On this page
Circular sectors and a lune opening the quadrature series
Three circular-sector figures run across the top of the sheet and a curved-sided lune (falcata) is drawn at the right margin, each marked with letter labels. They belong to the study of squaring lunes and sectors that Leonardo develops on the folios that follow. Additional demonstrative writing surrounds the figures but is not included in the transcription for this page.
The bristle of the ox that seems to live in water
The note claims that the bristle of an ox, put into dead (still) water in summer, takes on feeling, life and motion of its own accord, together with fear and flight, and feels pain. As proof, Leonardo says that if you squeeze it, it twists and writhes; returned to the water, it 'takes flight' and lifts itself away from danger.