Weights on inclined planes and a cylindrical bellows valve
Equal weights on unequal slopes, and a leather bellows that must descend straight and frictionless
The page opens by noting that it completes matter left unfinished three folios earlier, then sets out triangular diagrams in which equal weights of 4 and 4 hang from a pulley over a double inclined plane (labelled b a c, d e, f g h). Leonardo's point is that equal weights on the equal arms of a balance resist one another's descent in the air, yet behave differently once they rest on unequal slopes. Below, a large drawing of a cylindrical bellows fitted with a cone valve is described: it must descend perfectly straight and without friction so the leather is not worn, and its reinforcing rings must sit on the outside to check over-dilation. A smaller valve detail labels its empty pipe a b.
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Equal weights that behave differently on unequal slopes
Even though equal weights on the opposite equal arms of a balance resist one another's descent while hanging in the air, they will not do the same once they touch along unequal obliquities. The triangular figures pair weights of 4 and 4 over a pulley to make the comparison.
Cylindrical bellows with a cone valve
The bellows must descend straight and without any friction so that its leather is not worn away. The rings that encircle and reinforce the leather are to stand on the outside, so as to prevent its excessive dilation.
Valve and its guiding pipe a b
A small valve detail is labelled b and a. The empty pipe a b forms the sheath for the face of the iron that keeps the valve running straight.