“Beethoven’s compositions more and more assume the character of studied eccentricity. He does not write much now, but most of what he produces is so impenetrably obscure in design and so full of unaccountable and often repulsive harmonies, that he puzzles the critic as much as he perplexes the performer.” (The Harmonicon, London, April 1824)
“Beethoven mystified his passages by a new treatment of the resolution of discords, which can only be described in words by the term, ‘resolution by ellipsis,’ or the omission of the chord upon which the discordant notes should descend.... Many of his passages also appear confused and unintelligible, by a singular freedom in the use of diatonic discords or discords of transition; many instances appear of passages by contrary motion, each carrying their harmonies with them.” (Musical World, London, March 1836)
Source: Lexicon of Musical Invective: Critical Assaults on Composers Since Beethoven’s Time by Nicolas Slonimsky (1953)