What wind-measuring device did Leonardo da Vinci design in the 1480s?

Leonardo da Vinci designed an anemometer in the 1480s to measure wind speed.

His design used a flat, hinged plate that wind pushed upward. The height of the plate could be read against a graduated scale, providing an indication of wind strength. It was intended to help study conditions for flying machines.

Leonardo’s device was not the modern cup anemometer, which rotates in the wind, but it belongs to the same broad family of instruments. The design is recorded in his codices and is often cited as an early practical attempt to quantify wind speed.

An anemometer measures wind speed; a wind vane, by contrast, shows wind direction. Leonardo also sketched other instruments for studying air and weather, but the hinged-plate design is specifically associated with measuring wind force.