"In keeping time Chopin was inflexible, and many will be surprised to learn that the metronome never left his piano. Even in his oft-decried tempo rubato one hand—that having the accompaniment—always played on in strict time, while the other, singing the melody, either hesitating as if undecided, or, with increased animation, anticipating with a kind of impatient vehemence as if in passionate utterances, maintained the freedom of musical expression from the fetters of strict regularity."