Philon of Byzantium was a Greek scholar and engineer who wrote a collection of books about the most important mechanical inventions of his time.

Philon considered in his writings the theoretical basis of mechanical contrivances: the law of the lever for pumps, war machines, and diving devices. He described an instrument for the demonstration of the expansion of air. This device might have been used as a thermometer, one of the earliest known.

www link :
Biography