Strength of wind as defined by the length of a 90 inch chain welded to a pole. Wind speed is determined by the length of horizontal chain, before it begins to droop down vertically. The stronger the wind, the greater the horizontal length before dangling downwards.
Dang, Elbert! Let's go hot air ballooning today! The wyoming windsock is only stretching out 30 inches! Let's go!
av ratstalker 29 mars 2013