B flat inserted into a D minor chord: Roger Scruton alludes to Wagner's description of this chord as introducing "a huge Schreckensfanfare—horror fanfare." When this passage returns later in the same movement (just before the voices enter) the sound is further complicated with the addition of a diminished seventh chord, creating, in Scruton's words "the most atrocious dissonance that Beethoven ever wrote, a first inversion D-minor triad containing all the notes of the D minor harmonic scale": Robert Schumann's song "Auf einer Burg" from his cycle Liederkreis, Op. 39, climaxes on a striking dissonance in the fourteenth bar. As Nicholas Cook points out, this is "the only chord in the whole song that Schumann marks with an accent". Cook goes on to stress that what makes this chord so effective is Schumann's placing of it in its musical context: "in what leads up to it and what comes of it". Cook explains further how the interweaving of lines in both piano and voice parts in the bars leading up to this chord (bars 9–14) "are set on a kind of collision course; hence the feeling of tension rising steadily to a breaking point". Wagner made increasing use of dissonance for dramatic effect as his style developed, particularly in his later operas. In the scene known as "Hagen's Watch" from the first act of Götterdämmerung, according to Scruton the music conveys a sense of "matchless brooding evil", and the excruciating dissonance in bars 9–10 below it constitute "a semitonal wail of desolation". Another example of a cumulative build-up of dissonance from the early 20th century (1910) can be found in the Adagio that opens Gustav Mahler's unfinished 10th Symphony: Richard Taruskin parsed this chord (in bars 206 and 208) as a "diminished nineteenth ... a searingly dissonant dominant harmony containing nine different pitches. Who knows what Guido Adler, for whom the second and Third Symphonies already contained 'unprecedented cacophonies', might have called it?" One example of modernist dissonance comes from a work that received its first performance in 1913, three years after the Mahler: The West's progressive embrace of increasingly dissonant intervals occurred almost entirely within the context of harmonic timbres, as produced by vibrating strings and columns of air, on which the West's dominant musical instruments are based. By generalizing Helmholtz's notion of consonance (described above as the "coincidence of partials") to embrace non-harmonic timbres and their related tunings, consonance