The Anemometer

It is used to measure the wind speed.

From 1734, it was possible to measure the wind speed by means of a recording anemometer.

The same instrument also measured the wind direction.

Before installing cup anemometers with electronic transmission on the mast, the wind speed could be measured with precision windmill anemometers.

These small instruments were kept in a case and always accurately lubricated. They were always used along with a small 15 or 20-second glass.

The needle was set to 0 and then the device was placed facing the wind for the duration of a glass. The dial was graduated both in m/s, and in degrees from 1 to 10 or 12 Beaufort degrees. 

The Richard anemometer had a rotor, a revolution counter, and a seconds counter all in one single piece.

After 100 seconds of wind exposure, the instrument would display the wind speed in m/s.