Smoke to Suffocate Castle Defenders
A siege technique of choking fumes, with a drawing of a tower engulfed in clouds of smoke.
A short note records how the Germans smother the defenders of a castle with the smoke of feathers, sulphur and orpiment, made to last seven or eight hours. Leonardo adds that wheat chaff yields much lasting smoke, as does dry dung mixed with olive residue (sansa) or oil dregs. The sketch above shows a tower wreathed in billowing clouds of smoke, with a faint pair of beams drawn at the foot of the page.
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Choking fumes of feathers, sulphur and orpiment
The Germans smother castle defenders with the smoke of feathers, sulphur and orpiment (risalgallo), making it last seven or eight hours. Wheat chaff makes abundant, durable smoke, and so does dry dung, provided it be mixed with sansa (pressed olives with the oil removed) or with the dregs of oil.
Tower engulfed in smoke
A crenellated tower is drawn surrounded by rolling clouds of smoke, illustrating the smother-fume method described in the note. Diagonal hatching suggests the fumes rising against and around the structure.