Mersenne’s Universal Harmony 119
Figure 7.8
(a) Mersenne ’ s cross-sectional diagram of a bell. (b) Mersenne ’ s diagram of an organ.striking a bell at different points elicits different sounds. Noticing that, in different bells,
the various overtones appear with different strength, he brings forward information about
the possible combinations of metals, showing that he had studied the artisanal knowledge
of bell-makers, though many of them “ have been wrong in all sorts of bells, making them
too heavy, or too light, or too straight, or too large. ”^36 He lists the most successful mixtures
of metals and the best proportions for bells but is not able to account for them mathemati-
cally. He compares the various overtones of bells with those of strings, the voice, and
organ pipes.^37
In his preliminary summation, the movements of all “ solid and hard bodies which are
made of complete vibrations, which hold some elasticity, are species of tremblings and
shakings. ” The problem is “ how the shuddering is made without the bells being burst, for
if all their parts are moved, when they tremble, some must give way to the others ... [and]
find space for moving and vibrating. ” He concludes that the body must be “ more or less
porous, ” having “ a great number of small empty places ” as in the ancient atomic theory,
which he thinks “ can easily explain the vibration of bells. For when one strikes them
their atoms are stirred and crackled in changing place, and in occupying the spaces of
the small vacuums, and then they return many times into their ordinary place, and return
into the said vacuums until they become quiet. ”^38 Here Mersenne is in sympathy with his
close friend Pierre Gassendi, who was deeply interested in atomism, though it wasAB