SOUNDS OF LESBOS feeds a diatomic chain. Sappho's surviving pitch-data — Pythagorean tuning, the octave species, the quantitative Sapphic metre — becomes the excitation spectrum of a quantised lattice. Direction A plucks a note and drops it onto its phonon mode. Direction B reads the band structure back out as a lyre phrase in Sapphic metre. The bridge is not metaphor: the normal modes of a string under tension are the acoustic phonons of a 1-D elastic medium.