Against Vitruvius on small models
Leonardo sets out to disprove that models do not confirm the effect of large works
A full page of text, drawn upside-down relative to the notebook's normal orientation, in which Leonardo takes up Vitruvius's claim that small models are in no operation confirmed by the effect of large ones. He announces that he intends to prove this conclusion false, using the very example Vitruvius employs: the auger, where a man's power bores a hole of a given diameter, and a doubled diameter is said to require far more than doubled power. The passage breaks off in the middle of his rebuttal, continuing onto the following leaf. The argument continues the proportional-scaling demonstration begun on the facing page.
On this page
Vitruvius's claim about models and its rebuttal
Vitruvius holds that small models are in no operation confirmed by the effect of the large ones. Leonardo means to show this false using Vitruvius's own auger example, in which a doubled hole-diameter is said to need much more than doubled power. He begins his reply where the text breaks off.