Thermoscope

An early form of device for showing changes in heat, typically a tube in which a liquid rises and falls. The first known thermoscopes were by Galileo Galilei in about 1592; the first clear diagram of a thermoscope was published in 1617 by Giuseppe Biancani. The addition of a scale makes it a thermometer, but this quantification (and the concept of temperature) did not arise till later.

References

• The Galileo Project The Thermometer
• Benedict, Robert P.,(1984) Fundamentals of Temperature, Pressure and Flow Measurement, 3rd ed, Wiley ISBN 0 471 89383 8, Chapter 1 "Early attempts to measure degrees of heat"