1000850 The twisted beard of a wild oat which is used in the hygrometer of many old mercury wheel barometers. It does require a small piece of dried grass to be used as a 'pointer', the oat beard twists left and right according to dry or damp conditions and was a crude indicator of moisture in the air. (see book 'Care and Restoration of Barometers' for details of fitting if required. Sorry, below our minimum order value of £18 so you are unable to order on its own.
