A very specific error indeed

The following is an account of the conductor Hans von Bülow:

The newspaper critics Bülow continued to despise because of their self-importance, and he lost no opportunity to expose their musical ignorance.  On one occasion, Bülow, at a public rehearsal in the Philharmonie, remarked upon a printing error in the second horn part of the Breitkopf edition of the Beethoven symphonies.  A well-known critic, who was present, waited until the end and came forward to ask Bülow to confirm the exact bar number of the mistake.  Bülow opened the score at random, pointed to the horn part and said, “There it is”.  The critic looked briefly at the bar in question and then said, “Quite right, of course, of course”.  Bülow had correctly sensed that the knowledge of this “authority on music” did not even extend to transposing the horn parts, and dismissed him with a sarcastic smile. 

Cited in Walker, Alan (2009) Hans von Bülow: A Life and Times. USA: Oxford University Press, p. 392.