Mersenne’s Universal Harmony 109
natural philosophy. Music played a crucial role in the discoveries that Mersenne himself
made and was constantly present in his correspondence.
Both on the large and the small scale, Harmonie Universelle shows the closest interac-
tion between practical music, its theory, and natural philosophy. Its subtitle proclaims that
it treats “ the nature of sounds, and of movements, ” as well as of “ consonance, dissonance,
genres, modes, composition, voice, chants, and all sorts of harmonic instruments. ” Its
elegant frontispiece ( figure 7.3 ) depicts Orpheus playing his lyre to charm the animals, in
which a lion lies next to a lamb, identifying the scene with the biblical vision of the end
of time and the divine singer with the Redeemer. This is indeed a vision of universal
harmony. Through his motto from the Psalms, Mersenne depicts his project as a confession
of “ thy truth with the instruments of the psaltery, ” in which singing and the harp itself are
not only the means of divine praise but also the instruments through which divine truth is
revealed. In the process, warring animal natures are subdued: the lion looks down rather
fiercely on his prey, who turns demurely away. The image hints at the possibilities but also
the limits of taming the passions; only the innately peaceable animals seem totally
immersed in the music, like the ecstatic turtle at Orpheus ’ s feet or the rapt sloth in the tree
above his head.^15
Mersenne begins with “ the nature and properties of sounds, ” “ the movements of all sorts
of bodies, ” and “ the movement, tension, force, weight, and other properties of harmonic
strings and other bodies, ” followed by treatises on the voice, on chant, consonances, dis-
sonances, the art of composition, and all sorts of instruments. He situates his encyclopedic
treatment of music in relation to the new Galilean theories of motion. He does not disguise
his adherence to the heliocentric view, but (in contrast to his preliminary Trait é de
l ’ harmonie universelle ) he does not devote a section of the new book to astronomy or
cosmology, standard topics though they were in treatments of musica mundana , thereby
avoiding dangerous debates. He anticipates that, though practicing musicians may find his
first books “ the most laborious of all, ” they will still understand the necessity of connecting
music with fundamental physics. In short, he imagines his readers to be, like himself,
passionately interested in music as practical art and physical phenomenon. He believes
that they, like he, want to confront facts established by precise experiments, not just plau-
sible reasonings or empty words; he takes nothing simply from authority, not even Gali-
leo ’ s, but wants to test assertions for himself and urges his readers to do likewise. As a
prime example, in his preface he emphasizes the surprising result of that archetypical
Galilean experiment, the “ Pisan drop ” : “ two bodies of the same size but one weighing
eight times more than the other will fall in almost the same time when dropped over one
hundred feet. ” He takes this sheer fact as crucial in light of the long-received Aristotelian
arguments that deny this. As he insists on positive proof by experiment, he also defends
using the technical terms of the art of music, whose practical aspects are, for him, a direct
source of experimental knowledge.