Double windmills. Two sets of four brass vanes on an axel with a leaf spring connected to it, on a brass and wooden stand. The vanes are facing the direction of rotation on one set and are twisted away from it on the other set.

ABDNP:200041a

Demonstration of air resistance. Double windmill each with 4 vanes : first set vanes fixed perpendicular to direction of motion; second set of vanes can be rotated individually around axis of support arm to give range of resistance from maximum to minimum. Powered by single leaf spring with release arm. Cross cut on underside base and evidence of former base cover. Inside frame arm stamped ' Univ. Abdn. Nat. Phil. ' See article on 'James Ferguson & the Double Windmills' by John S. Reid in Bulletin of the Scientific Instrument Society June 2003

John King

Early: 1781 Late: 1789

brass wood spring metal, overall height 230 mm ; base height 83 mm ; width

Physical Object

Europe, Scotland, Aberdeenshire Aberdeen

Acquisition Source: 1823 inventory