Robert Fludd, De metaphysico macrocosmi et creaturarum illius ortu (Oppenheim, 1617). The John Rylands Library, Manchester (Rylands SC13099D, p. 90)

This is an engraving of a monochord with its ‘single string’ intersected by circles and arcs labelled with musical ratios and elements of the universe. The monochord was associated with Pythagoras (c. 570–495 BCE), a mathematician and musicologist. It comprises a taut string that is tightened or relaxed by a tuning peg and a movable bridge to adjust the length of the string. Pythagoras found that if the length of the string is halved, an octave is produced, indicated on the engraving by the annotation ‘gg’ at the top of the string and ‘G’ at its mid-point. According to Pythagoras, musical intervals are expressed in ratios; for example an octave refers to the interval between notes where one has double (or half) the frequency of the other: that is 2:1. The monochord was used for teaching, tuning and experimentation until the emergence of more accurate instruments in the late nineteenth century.

In 1618, Robert Fludd (1574–1637), a British physician, mathematician and cosmologist, theorised a Divine Monochord using the monochord to illustrate the divine order of the universe proposed by Ptolemy (c. 100–170). Even into the seventeenth century it was generally believed that the celestial bodies, such as the sun, moon, stars and planets, orbited the earth in accordance with God’s plan. Furthermore the movement of these celestial bodies produced musica mundana (music of the spheres). Fludd’s famous image of the Divine Monochord provides a complex diagram of musica mundana that illustrates cosmic relationships and musical intervals, based on the assumption that the universe is built according to the ratios found in musical intervals. In his Divine Monochord, the cloud at the top symbolizes heaven while the word Terra, at the bottom, is the Latin for earth. Fludd noted the different pitches representing the three hierarchical levels of the universe. The higher the pitch, the further away it is from the earth. The first level, elemental, is bounded by notes A to C; A corresponds to water (Aqua), B to air (Aer), C to fire (Ignis). The second, ethereal, level is represented by notes D to d. The moon is D, Mercury is E and Venus is F. The sun (note G), bearing a face, lies at the midpoint of the monochord, halfway between earth and heaven. The other planetary bodies, Mars, Jupiter and Saturn are represented by notes a, b and c. The division between the ethereal and empyrean levels at note d is emphasised by the ring of stars above which notes e, f and g lead upward to heaven.

In another image (‘Man the Microcosm’) Fludd stretches the string of a monochord over the body of a man – similarly inscribed with orbital circles connecting ‘man’ to the universe – to symbolise the movement of a soul between earth at the body’s feet and heaven above its head. Viewing the sound box of Fludd’s Divine Monochord as a body, the string represents life controlled by the hand of God. The action of God tuning the Divine Monochord not only underlines the otherworldliness of God, but also his mightiness. The rays of light around the cloud symbolize the power of God. Depicting the head and shoulders of God, or even just his hand, in a cloud was a familiar iconography in the Middle Ages that persisted into the early modern period. In other engravings of Fludd’s Divine Monochord, the hand of God is replaced by a triangle symbolising the Holy Trinity.

On the side of the sound box, are the words tonus and semi. Some critics, such as the astronomer Johannes Kepler (1571–1630) and polymath Marin Mersenne (1588–1648) pointed out that the intervals labelled by Fludd as ‘tone’ or ‘semi-tone’ were sometimes transposed. For example, the interval between E and F should be a semi-tone instead of tone. Despite the slight ‘error’ that Fludd made, his Divine Monochord brought together ideas about the mathematical ratios governing musical consonance, the structure of earth and heaven and the movement of celestial bodies, and the nature of man.

Jason Sun

Further Reading:

Penelope Gouk, ‘Transforming Matter, Refining the Spirit: Alchemy, Music and Experimental Philosophy around 1600’ in European Review 21:2 (2013), 146–157.

David Huckvale, The occult arts of music: an esoteric survey from pythagoras to pop culture (Jefferson, NC: McFarland & Co., 2013).