Rehearsal of The Ugly Duckling, sung by Koshetz and conducted by Bâton. The circumstances were dreadful, since Bâton did not know the piece at all and the orchestral parts were full of mistakes. The wretched copyist had transposed the clarinet parts down three semitones instead of up three semitones, so that they were in E flat rather than A. In the afternoon I buckled down and rewrote the clarinet parts myself. Transposing up a diminished fourth fourth is very difficult. Luckily I hit on the idea of writing them in B flat, so that they could simply be transposed up a fourth. I barely finished in time for the concert.