Music and the Making of Modern Science

206 Chapter 13

tested the constancy of rotation. Hippolyte Fizeau and L é on Foucault subsequently used

this device to measure the speed of light in water and air, important experiments leading

up to the theory of relativity.

In 1831, Wheatstone and Faraday returned to the transmission of sound. To illustrate

the much greater speed of sound through solid media than through air, Wheatstone called

for linked rods reaching forty feet into the cupola above the auditorium. A tuning fork

applied to the upper end transmitted its vibrations to a sounding board at the bottom end

with striking clarity. Faraday also brought Wheatstone ’ s Enchanted Lyre (see figure 13.3 )

to the Royal Institution, its eerie resonance demonstrating the difference between longi-

tudinal and transverse transmission by changing the angle of the lyre with respect to the

rod connecting it to the hidden piano. Wheatstone described similar experiments with

violins, flutes, and other instruments, finally transmitting the sound of an entire orchestra

through a sounding board linked to a rod, resulting in a faint sound at the distant recipro-

cating soundboard: “ but on placing the ear close to it, a diminutive band is heard, in which

Figure 13.7

Wheatstone ’ s rotating mirror apparatus to measure the speed of electricity in wires (1834). To test the stability

of the rotation, he held a piece of paper touching the rotating arm ( Q ) to produce a pitch.