The great crossbow, with bombard and torsion engines
Giant crossbow on a wheeled carriage with worm-screw spanner and two triggers, plus a bombard and a four-cord torsion engine
The lower half-leaf carries a great crossbow mounted on a wheeled carriage, with a long note giving its dimensions: arms spanning 42 braccia, a stock 2 braccia wide and 40 long that carries a 100-pound stone and lowers for travel. Around it are two firing mechanisms — one released by a mallet-blow above the nut, the other silently by a lever — and, below, an endless screw for drawing the string. The upper half-leaf gathers further war machines: a bombard mounted on a heavy timber frame ('beams') and an instrument that stores force by twisting four cords around a central piece of wood. The Ambrosiana catalogue also classifies brief geometric notes on proportion here, and some further writing on the sheet is left untranscribed.
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Giant crossbow on a wheeled carriage
The great bow opens 42 braccia across its arms; its stock is 2 braccia wide and 40 long and throws a 100-pound stone. On the march the stock drops and the bow lies flat along its length.
Two release mechanisms for the string
Two triggers are compared: the first lets go from the blow of a mallet above the nut; the second produces the same effect with a lever and 'without noise.'
Worm screw for spanning the bow
Below the carriage an endless (worm) screw serves to draw back the crossbow's string.
Bombard on a timber frame
At the right of the upper half-leaf a bombard is mounted on a large machine, its bed noted simply as 'beams.'
Torsion engine of four twisted cords
An instrument stores force by the torsion of four cords set around a single piece of wood in the middle.