 Meyerbeer did not operate on the basis of any theory or philosophy of music and was not an innovator in harmony or musical form . In the words of John H. Roberts , " He had a rich fund of appealing if somewhat short @-@ <unk> melody , commanded an increasingly rich harmonic vocabulary , and was a master of brilliant and novel orchestral effect . But he had very limited skill in thematic development and even less in <unk> combination . " 
