A drawing of a hilltop with stratified rock bursting out of the ground and heaps of fragmented boulders in the right background. Melzi's number 161.

The perspective and scale, and the relationship between the parts of the drawing, are hard to grasp – the motifs seem to have been added individually without any overall compositional plan, a characteristic of drawings done in front of the subject. This effect is prominent in Leonardo’s Arno landscape of 1473 (Florence, Uffizi), and some 40 years later we see here, at lower left, the same swirling, overlapping pen lines that serve little descriptive purpose, but are Leonardo’s intuitive attempt to capture the invisible forces that bind the landscape together.

Leonardo had a profound awareness of geological processes. He wrote about the immense forces that formed mountain ranges, and the huge periods of time over which they weathered. Leonardo also made many drawings of rock formations; some were imaginary, but here he made a careful record of an outcrop of stratified rock bursting out of the earth.

Text adapted from Leonardo da Vinci: A life in drawing, London, 2018