1. An ergonomic control device for the setting of a given single variable physical property of a structure between a maximum setting and a minimum setting; said structure having a control input connected thereto for adjusting said variable property to any of a plurality of settings between said maximum and minimum settings; said control device having first, second, third and fourth separate manually operable control elements which are operatively connected to said control input; said first and second control elements being operable to set said variable property of said structure at said maximum setting and said minimum setting respectively; said third and fourth control elements being vernier controls and being respectively operable to adjust said variable property from said maximum setting and toward said minimum setting, and to any of said plurality of settings and from said minimum setting and toward said maximum setting and to any of said plurality of settings.