Weathervane
Thomas Jefferson had a compass rose installed on the ceiling of the Monticello Northeast Portico connected to a weathervane for use in his life-long weather observations.
The compass rose on the ceiling of the Northeast Portico was connected to the weathervane on the roof. Thomas Jefferson and his family could determine the wind direction without stepping outside by looking from the windows in the Entrance Hall and in the North Square Room and South Square Room.