Machine for raising columns, and how an arch loads its columns
A tall hoisting frame, crossed vault ribs, a chimney and a polyhedron, with an experiment on arch loading.
The upper half of the sheet is dominated by a tall hoisting frame set on a long horizontal sled, captioned as a machine for raising columns. Below it Leonardo draws two crossed sets of timber arch ribs and a polyhedral cage, while a small chimney is sketched at upper left. The principal note argues, through the thought-experiment of a man braced on a balance inside a well shaft, that a weight set on an arch does not press fully onto its supporting columns.
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A weight on an arch does not fully load its columns
Leonardo claims that the greater the weight placed on an arch, the less both the arch and its load press upon the supporting columns. He proposes a proof: a man stands on a balance in the shaft of a well, then spreads his hands and feet against the walls, whereupon he weighs much less; adding a load to his shoulders makes him press harder against the walls and lightens the balance still further.
Machine for raising columns
A tall pyramidal hoisting frame rises from a long horizontal sled, with a threaded shaft at its apex and a small winch wheel at the base. It is a rig for lifting and setting up columns on a building site.
Crossed rib arches (groin-vault ribs)
Two interlocking sets of pointed timber ribs form a crossed vault framework, drawn in relation to the note on how arches carry their loads onto columns.
Polyhedral figure
A cube is enclosed within an open cage whose crossing edges frame an octagon at the centre, one of Leonardo's studies of solid geometry.
Sketch for chimneys
A small sketch at the upper left is captioned as a design for chimneys; the accompanying note survives only as an opening fragment.