From AMS Glossary
A type of pressure-tube anemometer, named after the inventor, in which the pressure head is located on the windward end of the wind vane so that it is kept facing into the wind.
The suction head is mounted concentrically with the shaft, near the bearing that supports the vane, and develops a suction that is independent of wind direction. The pressure difference between the suction head and the pressure head is proportional to the square root of the wind speed and is measured by a specially designed float manometer with a linear wind scale. The Dines anemometer was first described by William Henry Dines in 1892 and had all the essentials of the final form of the pressure-tube anemometer. With various modifications, the Dines anemometer remained a useful wind measuring device into the 1960s.