The indication of the metronome tempo was added by Chopin in GC in pencil, hence in the last phase of preparing the Stichvorlage manuscripts for print. Differently than at the beginning of the Etude, the composer added the indication only in this copy. In EE3 it was undoubtedly added on the basis of comparison with GE.
Compare the passage in the sources »
category imprint: Differences between sources; Corrections & alterations
issues: EE revisions, Authentic corrections in GC
notation: Verbal indications
