EXHIBITS > The inventions of Archimedes >
The density metre of Archimedes
It was an instrument used to measure the relative density of liquids. The density metre is allegedly invented by Archimedes and its operation is based on his well- known principle of buoyancy. It consisted of a graduated metal tube (closed at one end) which was immersed in the liquid to be tested. The density of the liquid was indicated by the subdivision of the instrument which corresponded to its equilibrium position.
SOURCES: "Synesius bishop of Ptolemais in Cyrene, letter to Hypatia"