Philo thermometer

A Philo thermometer.

In thermometers, Philo thermometer is a temperature measuring device in which a tube from a hollow sphere is extended over a jug of water operating such that if the sphere is placed in the sun, bubbles will be released as air expands out of the sphere; conversely, when moved into the shade, water rises in the tube as air in the sphere contracts, as pictured adjacent. [1]

This device was invented by Philo of Byzantium (c.280-220BC), and is said to be the first thermometer-like device.

Influence
Philo's thermometer design was described in a pamphlet published by him, and later read by those including Greek engineer Hero and German engineer Robert Fludd.

References
1. McGee, Thomas D. (1988). Principles and Methods of Temperature Measurement (Philo, pg. 3; Fludd, pg. 3-4). Wiley-IEEE.

External links
● Philo of Byzantium – Wikipedia.

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