Reconstruction of Philo's Thermoscope

Reconstruction of Philo's thermoscope, primitive temperature measuring device invented by Philo of Byzantium, 2nd century B.C.

Reconstruction of Philo's thermoscope apparatus used in early experiments demonstrating the heating and cooling of matter. When the lead globe is warmed, the air inside expands and pushes its way up the tube, which is immersed in water. If the heat is strong enough, bubbles of air escape. When the globe is cooled, the air contracts and water is drawn back up the tube. Philo (280-220 BCE) was a Byzantine scientist and was probably the first to record the contraction of air in a globe over water when a candle is burnt in it.