Ballistics Experiments, a Domed Church and the Physics of Sound

Air, voice and the impossibility of bodiless spirits

There can be no voice without movement and percussion of air, no percussion without an instrument, and no incorporeal instrument; therefore a spirit can have neither voice, form nor force, and where there are no sinews and bones no force can act. Water descending one ounce per mile is said to move a quarter-braccio per musical beat, doubling as the descent doubles. The note ends: flee speculators whose reasoning is not confirmed by experience.

Crossbow experiment: where a shot arrow bites hardest

To find at what part of its course a violently shot projectile strikes hardest, shoot arrows from a crossbow into a mass of fresh earth at intervals of 25 braccia out to 400. Where the arrow sticks deepest, that part of the flight is strongest, whether at a third, a quarter or a fifth of the way.

Small trebuchet: counterweight and range

If the small trebuchet (briccola) throws a stone 20 braccia with a counterweight of 10, test whether a counterweight of 20 throws it twice as far. Throw fresh earth wrapped in paper, so that it neither bounces after impact nor sticks to the machine.

Centrally-planned domed building

A small sketch at the upper right shows a centrally-planned building crowned by a dome, a 'building of central plan'.

Raising a beam through a window

Two views of a window with suspended beams illustrate a method to raise and set a beam through a window with ease.

Lineamenti di un volto: mento, bocca, naso.

Edificio a costruzione centrale1, con:

Figura di balestro e ostacolo a forma di parallelepipedo, con:

Piccola briccola, con:

Due figure di finestra, travi sospese, con:

Outlines of a face: chin, mouth, nose.

Building of central plan, with:

Figure of a crossbow and a parallelepiped-shaped obstacle, with:

Small trebuchet (briccola), with:

Two figures of a window, suspended beams, with: