Anemometer

The Dines anemometer was connected to the weather vane on top of the weather cabin, on the roof of the observatory. This instrument measured wind speed, direction and force.

The head part of the anemometer is the highest point - it turns according to which way the wind is blowing. This would spin rods, which are connected to two pens down in the weather cabin. The anemometer has a clockwork cylindrical plate, on which graphed paper is mounted. This plate needs to be wound up once a day, and turns continuously. The wind pushes the calibrated weather vane, turning the rods and activating the pens, which draw wind direction on the paper.

Wind speed is measured by creating differential pressure in two tubes. These tubes are positioned next to the weather vane, a good 10 meters or more above ground level. Wind rushes down the pitot tube, creating pressure, and second tube is perforated, so that air rushing past creates suction. Down in the weather cabin, the cylindrical anemometer tank holds water. A float, connected to an arm, sits on the water - and with force of the wind down the tubes, the water responds, moving the arm. A pen on the end of the arm registers the movement on paper.