Arch Construction, Post-Raising, and the Bombard-Rocket Note
A proportional arch in red chalk, a workman raising posts, and why a bombard breaks defenses
The main red-chalk drawing sets out the construction of an arch, whose span is stepped down in the proportions 8, 4 and 2 braccia, with a quarter-circle swung from a right-angled frame. A second sketch shows the mounting of one post upon another, accompanied by the small figure of a workman. A pen note promises a proof and reason why the bombard breaks through defenses, arguing it by the example of the rocket.
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Geometric construction of an arch
A right-angled frame at the top carries a quarter-circle arc swung as if by compass, the construction of an arch. Its dimensions are stepped in the proportions 8 braccia, 4 braccia and 2 braccia.
Raising one post upon another
A red-chalk sketch shows the mounting of one post above another, a device for raising or erecting heavy uprights. It is accompanied by the small figure of a workman.
Why the bombard breaks defenses
A pen note announces a proof and reason why the bombard breaks through the defenses. Leonardo says he will argue it by the example of the rocket.