Gear-trains and a bombard, with multiplication tables
Mechanical advantage of lever and pinion, geared force multiplication, and columns of figures
The upper fragment's 109a verso is recorded as void of original content, showing only faint bleed-through, while the lower 109b-verso fragment carries gear-trains and a slender bombard. Leonardo reckons mechanical advantage — the handle-lever making a pound worth twenty and the pinion five, so a hundred in all — and lays out geared multiplications of the mover's turns. Columns of multiplication by twelve fill the margins, with further figures added in another hand.
On this page
Mechanical advantage of handle-lever and pinion
Beside groups of gear-trains Leonardo reckons the force multiplication: the lever of the handle makes one pound worth twenty, and the pinion worth five, so that each pound is worth a hundred.
Geared multiplication of the mover's turns
Turning the sheet, another group of toothed wheels carries a progression from a thousand of the mover to twelve thousand, to a hundred and forty-four thousand, and beyond.
A long bombard marked 20
A slender bombard is drawn across the lower fragment, with the figure 20 set above the firearm's muzzle.
Columns of multiplication by twelve
Along the margins run repeated multiplications by twelve — from 144,000 to 1,728,000 to 20,736,000 — with a further reckoning added in another hand.