In circa 240BC, Philo of Byzantium (c.280-220BC) made the first thermometer-like devices. Philo published a manuscript describing an experiment in which a tube from a hollow sphere was extended over a jug of water operating such that if the sphere was placed in the sun, bubbles would be released as air expanded out of the sphere; conversely, when moved into the shade, water rose in the tube as air in the sphere contracted, as pictured adjacent. It is said that Hero of Alexandria (c.10-70AD) may have modeled is thermometer work on Philo and others, such as German engineer Robert Fludd (1574-1637), had access to PhiloÆs manuscript.

The next documented demonstration of a thermometer was described in Hero of Alexandria's circa 50AD Pneumatica. Documents show that Galileo read
Hero's Pneumatics in 1589.

One of the first crude thermometers was a nine-degree scale made by Greek-born Roman physician Galen in circa 175 AD. In particular, Galen considered boiling water to be the hottest body, ice to be the coldest, and a mixture of equal parts ice and boiling water to be the neutral body. He then installed four degrees above and four degrees below the neutral point, thus making a nine-point scale

73, Scott KF5JRV
Pmail: KF5JRV @ KF5JRV.#NWAR.AR.USA.NA

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