 Then Helmholtz had the idea of constructing more sophisticated resonators, made of spheres or cylinders of glass or metal. The resonators narrow to a small, hollow point at one end, and have a circular opening at the other. Helmholtz placed a small piece of hot wax at the small end, let it cool, and then inserted it into his ear or the ear of a subject. The prime tone of such a resonator is determined by its own composition and by the sympathetic vibrations of the ear. If a sound other than the prime tone of the resonator plus ear system is played, the listener hears only muffled noises, but “if the proper tone of the resonator is sounded, it brays into the ear most powerfully” (Helmholtz 1954 [1863], 43). Again, using resonators allows an experimenter to distinguish the component vibrations of music or ordinary noises, by first determining the prime or proper tone of the resonator, and then determining, using the resonator, whether the music or noise contains that tone.