Mill machinery, a friction study, and pyramid geometry
A mill wheel of the 'first motion' driving carriages, a balance diagram for friction, and a decomposed pyramid
Several mounted fragments carry mechanical, geometric and arithmetical studies. The largest concern a mill driven by a single wheel of the 'first motion' that serves several millstones through 'carriages', with a beam carried up into the floor or vault to bear the load in balance. Other fragments show a balance diagram used to study friction (with a worked proportional calculation), a pyramid decomposed into four equal pyramids on four bases, and columns of numbers such as 365 times 30.
On this page
Mill wheel of the first motion serving several millstones
A machine with 'carriages' (carrelli) is driven by a single wheel of the 'first motion', lettered d, c, b, a, A. Stopping a carriage and then restoring the water lets the common wheel run faster when it has fewer millstones to turn; a beam a m runs up into the floor or vault so its head is well bound above and below and carries the whole load in balance along the line a n.
Raising and lowering the mill wheel
A figure lettered a, n, m shows the way to raise and lower the mill wheel, that is, the wheel of the 'first motion'.
Balance diagram for the study of friction
An inverted diagram sets up an equality of weights on a balance: make the quarter of the number at a equal to the third of the number at S, so divide S by 3 and multiply the result by 4. Because the arms of the balance are equal, the equality holds among the weights.
A body resolved into four equal pyramids
A solid of four bases is resolved into four pyramids equal to one another, standing on those four bases.
Pyramid lettered by its faces
A pyramid is lettered a, d, c, b, e, with its component figures listed as first a b c d, second b c e d, third a e c d.
Columns of numbers
A calculation in the upper left corner multiplies 365 by 30 to give 10950. Another fragment carries an analogous grid of numbers used alongside the balance and friction studies.