This ancient weather instrument was invented by Galileo Galilei. Best known for his works involving gravity and astronomy, he developed the Galileo Thermometer based on his discovery that the density of liquids change as tempreture varies.
Each of the glass balls is exactly weighted by partially filling the spheres with liquid. When the tempreture rises the liquid in the glass cylinder becomes less dense and the balls sink slowly to the bottom.
The lowest tempreture ball within the group at the top of the thermometer tells the correct tempreture.
Measures 28cm tall and 6cm wide at the base.
