Instruments > Physics
Thermoscope
Inventor: Galileo Galilei - Maker: unknown
19th C. (replica)
Glass
Height 460 mm
IMSS, Current inventory: 2444
Copy of the
instrument to measure heat and cold invented by Galileo during his stay in
Padua. Vincenzo Viviani, in his Vita di
Galileo [Life of Galileo], states
that the thermoscope was designed by Galileo in 1597. This is confirmed by
Benedetto Castelli in his letter of September 20, 1638, to Ferdinando Cesarini,
in which he describes the use of the instrument. The thermoscope consists of an
egg-sized glass with a long neck. The jar is heated with the hands and
partially immersed, upside down, in a container filled with water. When the
hands are removed, the water rises in the neck. The experiment demonstrated the
changes in air density caused by temperature variations. Santorio had built a
similar instrument in Venice in 1612.