What repeating artillery design did Leonardo da Vinci propose with 33 small barrels?

Leonardo da Vinci proposed a 33-barrel organ with many small cannon barrels arranged in rows.

The design placed three groups of eleven barrels on a wheeled frame. While one group was firing, another could be loaded and a third could cool, creating a faster repeating sequence than a single cannon could provide. The weapon was intended for battlefield use and appears among Leonardo’s military-engineering studies.

The name “organ” refers to the visual arrangement of the barrels, which resembled the pipes of a musical organ. It was not a musical instrument. The design also did not provide truly automatic fire: human crews still had to aim, load, and ignite the individual barrels.

Leonardo’s proposal illustrates a recurring feature of his military inventions: he tried to improve practical operations by organizing repeated actions mechanically. Similar multi-barrel weapons existed in later periods, but Leonardo’s drawing belongs to the fifteenth-century tradition of volley guns and organ guns rather than to modern machine guns.