Buoyancy-driven wheel and a list of books on water
Air-filled vessels drive a wheel in water; a flask-rising test; planned books on floods and river defence
The left folio is filled with wheels whose radial arms carry small vessels or floats, a scheme in which air enclosed in the vessels is meant to keep the submerged wheel turning against the balance of its weights. Beside these, a note proposes building a working model and testing whether a flask rises obliquely from the bottom to the surface of the water. The right folio lists six planned 'books' on the uses of water, from overthrowing armies with diverted floods to lifting great weights and guarding cities against rivers. Further mirror-script text on the sheet is not included in the transcription.
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A wheel kept turning by air enclosed in its floats
The note describes floats a, b, c, d re-entering the wheel, driven by the air shut inside them, so that by their lightness they do not hinder the wheel's motion. As a float reaches point f on a line perpendicular to the channel, its buoyancy is meant to thrust f toward c and r toward g. Leonardo treats g r c f as a single rod and reasons about how the weights balance around the submerged wheel.
Building a sealed model of the device
Leonardo urges making a model with the mechanism secretly enclosed and only a plausible exterior shown. He notes that b and a are water, and that water within water has no weight, just as quicksilver has none within quicksilver. A point g is marked as water or air, with 32 rays specified for the wheel.
Testing how a flask rises through water
A short experimental note calls for testing whether a flask rises obliquely from the bottom of the water to its surface. Leonardo wants to determine by what degree of obliquity it ascends.
Six planned books on the powers of water
The right folio lists six intended books, each marked with a marginal d: on overthrowing armies with the force of diverted floods; on flooding armies by closing valley mouths; on floating cut mountain timber to safety; on driving boats against river currents; on raising great weights by simply increasing the water; and on guarding cities from the force of rivers.