What device did Leonardo da Vinci design to measure wind speed?

Leonardo da Vinci designed an anemometer to measure wind speed.

His concept used a light, movable plate that wind pushed upward. The height reached by the plate could be compared with a graduated scale, giving an indication of the wind's force. Leonardo recorded the design in his notebooks while studying flight and atmospheric conditions.

The device was not a modern cup or propeller anemometer, and it did not produce digital readings. Leonardo's design is important because it connected practical wind measurement with his investigations into birds, air resistance, and flying machines. Modern anemometers use rotating cups, propellers, or ultrasonic sensors, but they serve the same broad purpose: quantifying moving air. A related Leonardo design, the parachute, also depended on understanding air resistance, but it was intended to slow a falling person rather than measure wind.