Large Excavating Machine and Earth-Moving Weights
A great drum-and-cable machine, with a note reckoning shovelfuls, barrow-loads and chests of earth
The sheet is dominated by a large timber machine built around a great central drum or wheel, with cables running out over pulleys to counterweights and, at lower right, a chain of scoops or buckets — apparatus for moving earth or dredging on a large scale. Below and beside it are smaller studies of hoists, baskets and dome-shaped loads. A note at the bottom sets out a scale of earth-moving units: six shovelfuls make a barrow-load and twenty barrow-loads make a chest, so that at 25 pounds a shovelful a chest weighs 3,000 pounds. Further untranscribed writing runs along the lower edge of the sheet.
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Great drum-and-cable earth-moving machine
A large timber frame encloses a great central drum or wheel. Cables run out over pulleys at either side to hanging counterweights, and a chain of scoops or buckets is drawn at the lower right, suggesting a machine for lifting and moving earth.
Reckoning earth by shovelfuls, barrow-loads and chests
Leonardo lays out a scale for measuring excavated earth: one shovelful (badilata), six of which make a barrow-load (barella), and twenty barrow-loads making one chest (cassa).
Converting the earth units into pounds
Taking a shovelful at 25 pounds, the barrow-load comes to 150 pounds and one chest to 3,000 pounds — a worked chain of proportions from the smallest unit to the largest.
Hoists, baskets and loads studied below
A row of smaller sketches runs across the lower third of the sheet: a windlass or hoist supporting a basket, dome-shaped loads, and a further small lifting device.