Definitions of shadow, and weights on the balance
Primitive and derivative shadow defined; a suspended weight acts through the whole cord
The main column gives a set of definitions: the surface of every opaque body takes the colour of its object, shadow is a diminution of light, darkness a privation of light, and shadow divides into primitive and derivative, the primitive always serving as the base of the derivative. Leonardo adds that a shadow looks darker on a bright field and that a particular light gives better relief than the universal light of an overcast sky. In the right margin, balance diagrams with hanging weights accompany the rule that every suspended weight acts through the whole length of its cord.
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Definitions of shadow and its two parts
Shadow is a diminution of light and darkness a privation of light; every opaque surface partakes of the colour of its object. Shadow divides into the primitive and the derivative, the primitive always the base of the derivative, whose rectilinear edges weaken the farther they lie from it.
Particular light gives better relief
A shadow shows darker when surrounded by splendid whiteness and less clearly in a dark field. A particular light gives shadowed bodies better relief than the universal light, as a stretch of country lit by the sun stands out against one shaded by cloud and lit only by the general light of the air.
A suspended weight acts through the whole cord
Every suspended weight is entire throughout the whole length of the cord that sustains it and is entire in every part of it. The rule is set beside marginal balance diagrams carrying numbered weights.