1-151-066 - Oxford Science Archive/Heritage Images

'Galileo's thermometer', 1592. A 1994 copy of the air thermometer made by Galileo Galilei, the celebrated Italian scientist. This was probably the first instrument made for the measurement of temperature and consisted of a long thin glass tube fitted with a number of glass balls weighted to be of different densities in a liquid and arranged to sink one after the other as the temperature rose. This thermometer is more accurately known as a 'termometro infingardo'.