While the science of forecasting was becoming, in Cline’s day, a modern and objective one, much of the technology on which it depended was ancient. Of the big three, the anemometer used the oldest technology. Four fine, metal, hemispherical cups, their bowls set vertically against the wind, caught air flow. Because each cup was fixed to one of the four posts of a thin, square metal cross, lying horizontally, and because the cross’s crux was fixed to a vertical pole, when wind pushed the cups, they made the whole cross rotate. It made revolutions around the pole. In Cline’s day, the pole was connected to a sensor with a dial read-out display. The number of revolutions the cross made per minute—clocked by the sensor, transferred by the turnings of the wheels, and displayed on the dial—indicated a proportion of the wind’s speed in miles per hour. Rotating cups, wheels, and a dial: the anemometer was fully mechanical, with no reliance on electricity.
