How a man's shadow changes as he moves or bends
Shadow varies with distance from a fixed light, and infinitely as a standing figure bends
Two small lettered diagrams of a standing man accompany this page of Part Five, on how shadows change with motion. Leonardo proves that a man b c lit from a casts the shadow b c f, but on moving from c to e, with the light held fixed, his shadow changes in shape and size into the second shadow d e g. He then proves that a man a b, standing with fixed feet under an immobile light f, bends into c b and varies his shadow infinitely from a to c, since the motion runs through continuous, infinitely divisible space, so the shadow passes without limit from a o b to b c r.
On this page
A moving man's shadow changes with his distance from a fixed light
The shadows and lights of one and the same body vary as much as the man's approaches to and removals from the light. Let the man be b c, who, lit from a, casts the shadow b c f; when he moves from c to e, the light staying fixed, the shadow changes in shape and size into the second shadow d e g.
Infinite variation of shadow as a standing man bends
Let the light be immobile at f and the man a b stand with fixed feet, then bend into c b. The shadow varies infinitely from a to c, because the motion is made in space, and space is a continuous quantity, consequently divisible to infinity; therefore the shadow passes without limit from the first shadow a o b to the second shadow b c r.