Organizing Diggers: Barrows, Windlass and Labour Sums
Throwing spoil to one side; teams of men, wheelbarrows, a bucket-windlass, and reckonings
The recto's excavation study continues, here on how the spoil of a ditch should be thrown wholly to one side, with schemes marked 'this is feasible' and 'this order cannot be observed' for arranging the gangs of men. Leonardo counts how many 'turns' (tempi) it takes so many men to fill and empty a barrow, a barrow-load and a whole 'chest' (cassa) of earth, comparing methods and their cost in soldi. One passage describes a turning windlass with buckets poled at the middle that empties 1080 barrows, and later figures show basket- and barrow-devices worked by men. A dense field of arithmetic operations covers the right half, and the sheet also carries writing added upside-down.
On this page
Throwing all the spoil to one side
A section headed '15' treats the case when the earth of the ditches must be thrown wholly from one of the sides, with an accompanying scheme for the disposition of the workmen marked 'this is feasible'.
A turning windlass with mid-poled buckets
In the lower right corner Leonardo describes a turning windlass whose buckets have their pole in the middle, tipping to empty and then righting themselves, delivering some 8 barrows of earth at each turn; this device empties 1080 barrows.
Why an order of work cannot be kept
One scheme, Leonardo warns, cannot be observed: to widen the middle span to double, 2 ranks of men (6 in all) must be removed, and putting them at the head of the others still leaves the order impossible, so the confusion wastes time and expense.
Basket-devices worked by men
A figure shows 30 men who in 60 turns conduct and unload a 'chest' of earth; one man at a pushes baskets full of earth through openings by means of little rods or pegs a braccio long, the load being supported by the device so the men can endure longer.
Reckoning barrows, chests and turns
The right half is filled with long arithmetical operations reckoning spadefuls, barrow-loads and chests against numbers of turns and men (e.g. 1080, 360, 5760, 2160), computing productivity and savings in soldi per day.
