Solar rays through apertures, with sums and accounts
Optical notes on the camera obscura beside arithmetic and a memorandum of names
A crossed-out note on the right observes that the farther the second 'pyramid' of light lies from the intersection, the larger it grows upon the target, and that the circles formed at the angles of the aperture merge until the sun's ray remains round. Below it stand columns of arithmetical working, and at the left a memorandum listing personal names — Francesco, Ma, G, A, Allato — against numbers, with the remark that a figure of twenty is believed to be doubled. Faint diagrams of overlapping circles and of a squared aperture within concentric rings accompany the text. The sheet is lightly worn and the ink much faded.
On this page
The solar ray grows beyond the intersection
A crossed-out note observes that the farther the second pyramid of light lies from the intersection, the larger it grows upon the object. The circles created at the angles of the aperture penetrate one into the body of another, and the more they merge the rounder the sun's ray remains upon the target.
Columns of arithmetical working
Beneath the optical note run several columns of figures — additions and products including 1536, 1526 and 1612. They are the calculations that accompany the light study rather than a self-contained problem.
Memorandum of names against figures
A list at the left sets personal names — Francesco (repeated), Ma, G, G.a, A and Allato — against numbers. Leonardo adds that a figure of twenty is believed to be doubled, so the note reads as a private tally or account rather than a scientific entry.