A single stringed instrument used to scientifically measure pitched tones, the monochord was also considered by some to be an important alchemical tool. The 16th and 17th century paracelsian physician Robert Fludd (1574–1637) made use of what he called his mundane monochord to express not only his theories of music but also his esoteric ideas about divine cosmic harmonies.
An exhibition titled High Matter, Dark Language: The Philosophy of Robert Fludd was organized in 1984 at the Wellcome Library in London. The catalog for the exhibition states:
Fludd used the monochord mostly to depict the musical intervals and numerical
proportions, but he also went further than this and integrated other relationships such as
parts of the human body or the stars into the framework of the musical instrument… It is clear enough that Fludd meant to present in this way an ensemble of harmonies that was shown in its completest form in the Monochordum mundi. But he was never affected by the difference which exists for us between the harmony of an instrument and the symbolism of all the other harmonies.