(b. 1452, Vinci, d. 1519, Cloux, near Amboise)

Comparison of scalp skin and onion

Pen, ink and red chalk on paper, 203 x 152 mm
Royal Library, Windsor

Leonardo always attempted to record his analyses of what he saw and his experimental observations by connecting words and drawings, creating an encyclopedia of knowledge in the most diverse fields: optics, mechanics, biology, cosmology, mathematics, anatomy, geology. Here he compares the layers of the human scalp with those of an onion.