The resistance of spring-like supports
A coiled spring of many turns extends as easily as one of a single turn
This folio opens a study 'On the resistance of supports of the nature of a spring.' Leonardo argues that a single power will extend a coiled spring of very many revolutions with the same ease as a spring of similar thickness having only one revolution. He grounds the claim in his fourth proposition on bodies suspended from their supports, which holds that the weight of a hanging body acts entire along the whole length of its support and entire in every part of it. At the upper right, two weights hang from springs, one tightly coiled (A) and one drawn out (B), illustrating the comparison.
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A many-turned spring extends as easily as a single turn
One and the same power will extend, with equal ease, a coiled spring made of very many revolutions and a spring of similar thickness having only a single revolution. The two springs at upper right, holding weights A and B, set the coiled against the extended form.
Weight acts entire along the whole support
The claim is proved by the fourth proposition on bodies suspended from their supports: the gravity of suspended bodies is entire throughout the whole length of their supports and is entire in every part of them.